RODENTS
        PORCUPINE
 
Rodents are the largest order of mammals in the   Appalachian region (as well as the world), both in species and actual numbers.   In fact, 40 % of the worldï¿½s mammalian species are rodents.   The diversification of species has been a relatively recent and rapid   evolutionary event, with few extinctions, causing much consternation among   taxonomic botanists.
Rodents   are the "gnawing" mammals. Rodents are known for their pair of large   upper and lower chisel-like incisors.   Each incisor is a segment of   a true circle, continuously being pushed out of the end of the jaw.  Some species have incisor growth rates of one   inch per month. Unlike lagomorphs that have enamel covering the entire   incisors, rodents only have hardened enamel on the anterior (front) side of   the incisors.  This keeps a sharp   edge on the teeth, since the relatively soft posterior (back) side of the   teeth wears more quickly than the front. Also unlike lagomorphs, rodents have only one pair of upper incisors, instead of two permanent pair.   These incisors grow throughout the life of the rodent, kept in proper length by grinding of the teeth, not necessarily by gnawing plants.  Rodents lack canines, with the gap between the incisors and molars   known as the diastema.  This large   gap allows rodents to curl their lips backward into it while gnawing and chewing.  This behavior also permits the rodent to exclude unwanted   soil and debris from its diet.  This   also enables muskrats and beaver to eat underwater without inhaling water.
The grinding molars, or "cheek" teeth,  are a combination of vertical layers of dentine and harder enamel, which produce peculiar ridged patterns on the crown of the teeth, useful in classification by zoologists.
Rodents   have diversified to adapt to a variety of lifestyles including terrestrial   (mice and voles), arboreal (squirrels), fossorial (woodchucks), semiaquatic   (beavers and muskrats), and volant (flying squirrels). They range in size from   a third of an ounce of the harvest mouse, to the eighty pound beaver. All are   herbivores.
 
With the cooling and drying out of much of North America during the Tertiary and the Eocene (40-55 million years ago), forests transformed into grasslands, with the concurrent evolution and diversification of mammals.  Grasses became the most important of all the flowering plants and became the  nutrient source base of wildlife herbivores, domestic grazing livestock, and, in fact, mankind.  As the plants provided an abundant energy source, herbivores expanded in number and evolved into the ecological niches.  The ungulates evolved in the Eocene, the grass-eating marsupials arose 25-38 million years ago, and the voles of the microtus genus were the last to emerge, about 10 million years ago.  They have rapidly evolved and diversified for the past 6 million years filling all grassland niches.  
In order for rodents to fill out the grassland niches, two adaptations were necessary. First, as a result of the abrasive silicas in the cells of grasses, teeth, easily worn down by the silicas, became ever-growing throughout the life of the rodent.  The second adaptation was the ability of the herbivores to digest the complex carbohydrates contained in the fibrous portion of grasses through fermentation in the animal's gut by microorganisms.
The   success of the rodents became a problem in itself as carnivores evolved to   take advantage of this abundant new food source.  In response, special   reproductive adaptations evolved to enable massive birth rates within the rodent order.   This includes "postpartum estrus" in mice, with females being mated   within hours of birthing.
Rodents   have four toes (sometimes five) in front and five toes in the rear. 
 
Rodents   are known from fossils in North America dating back to late in the Paleocene   Epoch (60 million years ago).
Worldwide,   the rodent order is represented by 29 family, 468 genera and 2,052 species   (Nowak's Walker's Mammals of the World).  In North American, there are 9 families,  43 genera, and 217 species   (Jones' Checklist of North American Mammals).  In the eastern United States, there are   about 38 species and five introduced   species.
Rodents   include twenty nine species in the Appalachian region within five families.   These include the squirrel - which includes the groundhog - (Sciuridae),   beaver (Castoridae), porcupine (Erethizontidae),   mice, rat and vole (Muridae), and   jumping mice (Zapodidae) families.
 
Family   Sciuridae - Squirrels and Woodchucks
This   family can be divided into three groups; tree squirrels, flying squirrels, and   ground-dwelling squirrels (woodchucks and chipmunks). Tree squirrels are   diurnal, leading solitary territorial lives, living on nuts and fruit.  The woodchuck and chipmunk are also diurnal.  Flying squirrels are nocturnal and tend to be more omnivorous.  The family name means "shade tail", alluding to the large   bushy tail of the arboreal tree sciurids. Most of these family members stand   on their haunches to view their surroundings. Most members of the sciurids   have high birth rates to compensate for their high mortality, especially to   the weasel family (R-selected strategy populations, like the lagomorphs).  Squirrels come   in different sizes, habits, and habitats to maximize utilization of available   resources and to minimize competition among species.  They have the largest brains relative to their body size of all small   mammals and are the most intelligent of the rodents, as is reflected in their   complex vocalizations and social systems.  Some are arboreal (red, gray, and fox squirrels), some are   semifossorial - burrowers (prairie dogs, ground squirrels, woodchucks), and   some do both (chipmunks).  Some   hibernate (woodchucks), some enter deep torpor and feed occasionally on cached   food supplies (chipmunks), and many are active year-round. 
 
Squirrels   manufacture enzymes that enable them to eat the toxic amanita mushrooms.  However, like the pit viper that produces its venom and the skunk that   produces its musk, the squirrels produce these enzymes at a physiological   cost, thus ï¿½balancingï¿½ the benefit.
 
The front foot (hand) has four toes and the rear foot  has five toes.
Worldwide,   the 51 genera and 272 species of the squirrel family includes marmots,   woodchucks, prairie dogs, ground squirrels, chipmunks and tree squirrels   (Nowak's Walker's Mammals of the World).  They   range in size from 1/3 ounce of the pygmy squirrel, to 16 1/2 pounds of the   marmots.
Of 8 genera and 68 species found in North America,   seven species are represented in the Appalachian region (Jones' Checklist of North American Mammals).
 
EASTERN CHIPMUNK (Tamias   striatus) (treasurer, or storer; striped)
Appalachian   Region Distribution:   Throughout.
Continental Range: Eastern US   and southern Canada.  Nine   subspecies are recognized in eastern US,   with three in the Appalachian   region.
Abundance: Common
Population Density: 12 - 24/ acre;   with great annual variation.  
Size and Molt: Head and body five   to six inches; 2 ï¿½ - 4 ï¿½ oz. Two   molts.
Mammae: Four pair.
Habitat: Open deciduous forests;   especially rocky areas and forest/field bushy edges.
Active Period: Diurnal, with two   peaks of daily activity, with a midday slump. Inactive in extremes of winter and summer. Whether chipmunks hibernate or not depends on your source and   definition. They do not develop a layer of brown fat as does a true   hibernator. Instead, they go through periods of torpor of variable length   (rarely more than several days at a time) and frequency, normally starting in   October or early November.   Not all animals in a population will   become torpid.  During these periods   of torpor, studies reveal chipmunk respiration rates drop from 60 to less than   20 breaths per minute, and temperature drops from 100 to 42 - 45 degrees.   Chipmunks must wake about every two weeks to eat from their caches and defecate.  Will come out in mild weather any time.  (Mammal of Virginia states chipmunks have been seen in Blacksburg, VA   at 15ï¿½ F and three inches of snow on the ground.)  Individuals vary on length of torpidity, and can change from one year   to the next.   Additionally,   those of more northern habitat tend to spend more time ï¿½hibernatingï¿½ while   those of the south enter a torpid state only during severe winter weather.
Diet: Nuts primarily, with a   preference for hickory. Also eats fruit, mushrooms, some invertebrates,   annelids and arthropods (snails, worms, cicadas, and other insects). Chipmunks   spend a lot of time caching food in their burrow, especially during fall. The   food is used during waking time of winter's hibernation. Like the gray   squirrel, the chipmunk disperses its food caches to deal with theft.  It has a primary storage site in its burrow and numerous smaller   scatter hoards well hid throughout its territory.  As other chipmunks raid the primary storage site, the owner will refill   it from the scatter sites.  If no   thievery occurs, the scatter hoards often go unused, being left to rot or   sprout. Carries food in its cheek pouches. One chipmunk was found to be   carrying 70 sunflower seeds in its cheek pouches.  Another; 32 beechnuts.
Home Range: ï¿½ - 2 acres,   overlapping with others, with a smaller defended territory. Ranges may shift   annually for food, winter protection, or for finding mates. Males have larger   ranges than females. Within the home range is a protected territory, about 45   feet radius from the burrow opening.   Juveniles typically establish their own burrow systems near their   birthplaces.    A PA study found a home   range of .27 acre, with a 0.05 acre range when seeds were ripe.  An   Adirondacks report was 0.5 - 1 acre.
Social Structure: Solitary and territorial mammals, although known   to overwinter in small family groups. While ranges overlap, adults will strongly defend its   smaller territory in   order to protect itï¿½s food caches and during breeding time.   There are no lasting pair bonds.
Life Cycle: Under favorable   conditions, two seasonal breeding periods occur; with birthing in April and   July or August, with usually four to five per litter. The second birthing period   often consists of last years' young that failed to breed in the spring,   although a number of chipmunks breed in both spring and summer, unusual in   hibernators. This second birthing period does not appear in northern   populations.  Females are in estrus for 3   to 10 days.  Gestation period of   31 days, weaned at 5 to 7 weeks, at which time they first leave the nest. At   about 8 weeks, the female refuses to let the young re-enter the burrow and the   young are on their own. This dispersal may be abrupt or take a week or two. At   this time, adults will make continuous "chirps" near their burrows,   perhaps advertising their own territories. Chipmunks can be sexually mature at   approximately three months.  However,   most individuals do not breed for the first time until they are one year old.  Life span of two to three years,   although records of up to 13 years in captivity have been recorded .
Dens/Nest: Burrows fall into two categories.  They can be simple   with one or two tunnels used for a hideaway or for food storage, or quite extensive with over 100 feet of tunnels   (average is about 12 feet in length) used for nesting and storage.  Extensive   tunnel systems include a ten inch diameter nest chamber and separate chambers   for food caches approximately 3 feet underground. Surface opening is often   straight down and 1 1/2 - 2 inches diameter. Openings are often plugged with   soil each night and during the winter. Two side tunnels and openings may   exist, but are often plugged and not used. May occupy the same burrow system   for life. Burrows are not shared except briefly by the mother and young. Tree   cavities are occasionally used.
Tracks: Four front and five hind   toes approximately ï¿½ to 5/8" wide and a long, depending on   depth of imprint. Not common in winter since often will be hibernating.   Straddle is 2 - 3". Holes of 2 inch diameter leading straight down with   no trace of excavated soil is the diagnostic home of the chipmunk.
Scat: Small piles of four to six   rice-sized droppings.
Remarks:   Runs with bushy tail straight up. Perhaps best identified by itï¿½s sharp   chuck-chuck call in the woods as hikers pass. Well-developed cheek pouches   stores have been known to hold up to 32 beechnuts or 70 sunflower seeds. Food caches also are kept   throughout their range. Has been reported to overwinter with rattlesnakes,   purportedly sharing the snakeï¿½s warmth. Understandably, the chipmunk enters   the den after the snakes have become torpid, and exit in the early spring,   before the snakes lose their lethargy.  However,   chipmunks are a common prey of rattlesnakes.  The name chipmunk is of native Indian origin and probably relates to   its chipping call.
Chipmunks   from western Maryland are paler in color, and those from the Carolinas   brighter than those from other areas.  The   darkest individuals are found in the southern mountains, SW VA, Kentucky and   Tennessee.   Both albinos and   melanistic individuals are known.
There   are twenty four species of chipmunks in North America (Nowak's Walker's Mammals of the World - the Checklist of North American Mammals lists 22 species).  There is one eastern species and 23 (or 21) western species.  The 1994 edition of Nowak's states the smaller western species and   eastern species were formerly placed in one genus; Tamias,   but recent evidence had caused the western species to be split into a separate   genus, Eutamias.  Thus, at that   time, the eastern chipmunk was the only species in the genus Tamias." 
However, the 1999 edition of Nowak has the above two genera combined again in the same genus; Tamias.  It goes further to say, "There is general agreement that the issue is not settled and further investigation is needed on chipmunk systematics."  
 
WOODCHUCK (Marmota monax) (marmot; solitary)
Appalachian   Region Distribution:   Throughout.
Continental Range: Most of Canada and eastern US.  Four recognized subspecies,   with one in the study area.
Abundance: Common; in fact, more   common than in pre-Colombian times.
Population Density: W/H says 1 per   11 acres, occasionally up to 1 per 2 acres. Nowak reports a Wisconsin   average of 1/125 acres.  Other sources say 2-6/acres.    Populations tend to vary greatly year to year.  
Size and Molt: Head and body 12-20 inches; 5 - 12 pounds.   Hibernation results in the loss of about 30% of fall body weight.  However, weight loss immediately after emergence from   hibernation was much greater, with energy derived from remaining stored fat   reserves.  Males tend to be   slightly larger than females. One summer molt, taking 3 and ï¿½ weeks,   occurring from late May into September.
Mammae: Four pair. 
Habitat: Prefers open fields, but   found in mature woods, pastures and hayfields.
Active Period: Primarily   diurnal to crepuscular (morning and evening, like deer). Only spends one to   three hours above ground each day during the summer. True hibernators, entering their dens in   the first week of November  and emerging in early February   (sometimes requiring help for Feb 2).  Populations   further to the north may hibernate for up to four months, while more southern   populations may only hibernate for six to eight weeks or not at all.  Winter activity has been documented, but is atypical.  Older and fatter woodchucks enter their hibernacula first and emerge   first.
Diet: Herbivorous grazers.  Seasonal herbs and fruits, but known to taste grasshoppers, beetles and   snails. Does not cache food.
Home Range: 2 - 5 acres.  Woodchucks exhibit   little territoriality, except in the direct vicinity of their burrows.  Home range may shift from winter to summer den sites with corresponding shifts   in home  range.  Same sexes do not generally overlap, but males may overlap 1-3 females.  Female ranges are   generally smaller than males in the spring, but may become larger   than males after young are born before contracting again in the fall.  
Social Structure: Solitary, but may   live in small family groups with a male dominance hierarchy. Woodchucks are   not territorial, relying on a dominance/submission hierarchy to establish   avoidance of dominants by submissives where home ranges overlap.  Burrows are occupied by a single male, a mother and her young, or   occasionally, a male and a female.  Contrary to other marmots, the woodchuck is fairly aggressive.  This is a function of the length of the growing season.  The shorter growing season of the western marmots (60 days) requires   more time together to assure ample breeding (the Olympic marmot shares its   burrow with an adult male, two adult females and offspring from the previous   two litters).  The eastern   woodchuck can afford to be more picky (150 day growing season in PA).
Life Cycle: Mating shortly after   spring emergence (late February  to early April), one litter of four to five is produced in   April to mid-May.  Gestation period of 32 days. Weaned in six weeks and on   their own (chased off by mommy dearest) at two months of age (July).  By   fall, the young have established their own burrows.  Occasional young females will overwinter with the mother, like other   ground squirrels.  10 to 25   percent may reproduce in the subsequent spring at one year of age.  Most will mate in their second or, more commonly, third year. Life span   of four to six years. (Nowak reports 13-15 years).
Den/Nest: Will normally have both a summer and winter den. The   winter den (with normally only one opening) is often situated in brushy or   gently sloping wooded areas, whereas the summer den (with several openings) is in open,   flat fields. Occasionally, the winter den is used year round and by succeeding   generations. The burrow system   includes nest chambers, and/or a hibernaculum chamber (both about 15" wide and   10" high, lined with leaves and grass), and a latrine chamber.  The summer system has a number   of surface openings, easily identified by the excavated soil and a number of   nests. In addition to the main opening, there may be up to five more or less   obvious openings for emergency entrance or exit needs.  At least one of these hidden entrances will be a ï¿½plunge holeï¿½;   having a two foot drop from the surface.  Burrows may be four to five feet deep (reportedly up to 16 feet deep)   and 25 to 50 feet long.  Other mammals will use woodchuck burrows (skunks, foxes, opossums,   raccoons, rabbits, mice, and others).  A   woodchuck burrow can be distinguished from others by the fresh pile of soil at   the main entrance, since woodchucks clean out their burrows several times a   week.  Unlike foxes, woodchucks will not defecate outside the   entrance.  Rather, they use separate chambers in the burrow.
Tracks: Four toes on front feet, 1   ï¿½" by 2" long, and five hind toes, the front a little longer than   the rear.  Running gait shows four   feet tracks within 12" and 12" between sets of prints.
Scat: Quite variable, depending on   diet.  Often 2 1/2" long by   1/2" wide.  Can be longer   strings (if not separated) or more loose piles.  Fecal pellets are often deposited in a specific fecal chamber   underground or buried in the loose soil excavated outside of the burrow.  This burying behavior is unknown in other squirrels.
Remarks:   The common name comes from the Cree Indian word, wuchak.  The largest member of the squirrel family, with a flattened, bushy tail. Also,   the most widely distributed and best known of all the marmots.  The only representative of a genus of circumpolar   distribution. An accomplished climber and swimmer. True hibernators, with the   oldest (and fattest) entering the burrow first (late October). In Autumn,   after gaining 30% of itï¿½s summer weight (mostly in the form of a half-inch   layer of brown fat stored over much of the body, especially the back and   shoulders), the ground hog will line itï¿½s hibernaculum with grass and leaves   and then plug the entrances (to maintain constant temperatures and to keep out   curious visitors) before curling into a ball. During hibernation, heart rate   drops from 100 to four beats per minute (W/H says 100 to 15), respiration rate   drops to one breath per three or four minutes, and the body temperature drops   from 98 to about 40 degrees (W/H says 96 to 47). Males usually exit a few days   earlier than females in early March (similar to the hibernating jumping mice)   (W/H says one month earlier). This allows males to compete for good home   range and dominance over other males.  The   period of hibernation is about three to four months, with each 10 miles   northward adding one day of hibernation; given similar elevation.  Due to the shortened northern growing season, the emergence   is much more precise than in the southern range, thus enabling the well-known "groundhogs day" of Punxsutawney PA on Feb 2.  In an eight-year period, the PA emergence date fell between January 29   and February 8, regardless of the weather.  They will awaken   occasionally throughout the winter (about every two weeks) to defecate. This   may occur in special chambers below ground or, less frequently, on the   surface. They will emerge having lost approximately one half their fall weight   (W/H says 20 to 37%).  Ground hogs   have been observed every month of the year, even occasionally with snow on the   ground and temperatures in the 20ï¿½s.
Melanistic   (black) or erythristic (reddish-cinnamon) groundhogs are not uncommon. Albinos   are uncommon. Is known to climb trees for fruit and is a good swimmer. Itï¿½s   loud, shrill whistle gives it the common name "whistle pig" (call is   made with vocal chords; thus, not truly a whistle).  At the beginning of European man's introduction, woodchucks   were scarce.  As a result of human   disturbances, the range and population of ground hogs have increased over the   last 200 years.
 
In Kentucky, between 1964 and 1971, some 267,500 ground hogs were taken each year!
There   are six other North American species in the genus Marmota,   all located in the west, called marmots. 
 
ARTICLES
Appalachian   Region Distribution:   Throughout.
Continental Range: East of the Great Plains and south of the Great   Lakes. Basically, their range correlates with the eastern hardwood forests.   Five subspecies recognized in eastern US, with only one in the study area. 
Abundance: Common at lower   elevations; rare at higher elevations. Populations reflect "mast" years (acorn supply).   Much   higher numbers were found when the native American chestnut tree was common.                     
Population   Density: Highly variable, with highest populations in late August and   September.  Chapman and Feldhamer report   four WVA state forest densities over a six year period ranging from 0.44-1.0,   0.24-0.84, 0.2-0.44, and 0.32-1.4 per acre.  Our friend, Dr. Vagn Flyger of Silver   Spring, MD, found a range in his suburban yard backing up to the Northwest   Branch in Quaint Acres from 0.8-4.0 per acre over a three year   period.   2-20/acre in some studies,   others report 0.1-6/acre; max up to   20 / acre (public park densities can exceed 50 per acre).  
Size and Molt: Head and body is 9 to11 inches; ï¿½ - 1 ï¿½ pounds.  Sexes are alike in size and color.  Two molts; paler winter pelage, although the tail   molts only once in mid summer.  Northern   individuals are larger than southern populations.  
Mammae: Four pair.
Habitat: Mature oak and hickory   hardwood forests.  Land use may be highest in forested river bottomlands, river valleys and swamp hardwoods.  Extremely adaptable, they are found anywhere, except   spruce/fir forests, where red squirrels dominate.  Gray squirrels tend to prefer more dense woods than fox   squirrels.  The more large trees   an area has, the more gray squirrels will inhabit the area (larger cavities   and more food).
Active Period: Diurnal in winter to   crepuscular in summer, non-hibernating, primarily arboreal mammals.  Active year-round, but will will remain in their nests in very cold or   stormy weather until food forces them out.  W/H states that females are more active in spring and summer, with   males being more active in autumn and winter.  Most active in September and early October, burying   acorns (this is also the peak time for their arboreal activity).  Additionally, spring born (and some adult) fox and gray squirrels   frequently move to new locations at this time.  This dispersal period is also referred to as the ï¿½fall reshuffleï¿½,   with movement of 6 or more miles.  As   noted in the remarks below, this fall reshuffle, in conjunction with a failed   hard mast season, can result in massive fall migrations, more appropriately   called movements.
Diet: Nuts are the mainstay, with   buds, flowers, and roots in spring; maple samaras, fruits, berries, mushrooms,   and insects in the summer; nuts and fungi in fall and winter (specifically oak   and hickory nuts and maple samaras). They usually feed on just one food at a   time, changing the item as additional sources come along.  They are known to eat bark of dead trees   for the fungal mycelia within.  Shedd   even notes gray squirrels are known to eat bird eggs and frogs.  In February and March, they chew twigs of maples, oaks and pine. Winter   food storages, or caches, consists of each acorn buried separately, decreasing   the risk of losing an entire stash.  Adults obtain minerals from bones, antlers and turtle shells.  See Articles above for more information.
Home Range: Most studies indicate   one to four acres, up to ten acres (varies with food availability), larger for   males than females.  Chapman and   Feldhammer report 2 acres for males and 1.25 acres for females in a Maryland   study (Flyger).  Nowak reports 1.3 acres for males and 1 acre for females in a Virginia study.  Male home   range will overlap that of several females.  Overlaps   other squirrel home range.  Range   of gray squirrels are smaller than the fox squirrel.  Basically, their home range focuses on (and around) one nest tree, shifting   as  food sources become available.
Social Structure: Usually solitary,   shy and non-aggressive.    During the mating season, males will be territorial and exhibit   antagonism toward one another.  Males are polygamous.  The   same applies to females on a nest.  The   male provides no parental care.  Mammals   of Virginia say gray squirrels are gregarious and often congregate in   considerable numbers, while W/H says they  are not social, only gathering   in winter denning situations..   Chapman and Feldhamer says   both fox and gray are relatively nonaggressive toward either their own species   or the other species, but may share dens with a number of individuals of their   own species (Shedd says only males and juveniles will den together in winter,   with females ï¿½ probably pregnant - being cantankerous and denning by   themselves).  Wilson says at night   and during bad weather, as many as seven or eight squirrels may occupy a   communal den, where they will groom each other and conserve heat during cold   winter nights.  Among squirrels   with overlapping home range, especially at high densities, there is an   established dominance hierarchy, with the oldest (male or female) normally   assuming dominance (W/H says males over females, adults over juveniles, and   residents over immigrants).  Dominance   (i.e., aggression) appears at mating time, food concentrations (including bird   feeders), and at den trees. 
Life Cycle: Normally two litters of   about three (1-9) per litter per year (parturition about March and August).  Forsyth says only 20 to 40% have two litters.  Gestation period of 45 days, weaned in two months; about the same time   they first leave the nest.  Breeding   can begin as early as December.  Males   play no role in child-rearing.  The   spring brood stays with the mother until late summer, and the second brood   will often stay with the mother over winter. Young make leaf nests at about 18   weeks of age.  Young breed the   next year (may only have one litter).  Life span has been   up to 15 years, although 6 years is more the maximum. Wilson says   more like one year for the average.  One captured animal lived for 23   years.
Dens/Nest: Winter and summer nests are   made.  Will make winter nests in   tree cavities and summer leaf nests in branches (occasionally a winter leaf   nest is maintained).  A favored den tree may be   used for many years, but an animal always has several other nests where it can   escape enemies.  The tree cavity must be 12 inches deep and have an   opening at least 3 inches in diameter.  Often, several leaf nests   (called dreys) are built around   different food sources. Gray squirrels average 1 1/2 to 2 leaf nests per   squirrel. The leafy nest is composed of leaves and twigs forming a   water-resistant form lined on the inside with moss, grass, and shredded bark.   The main entrance is positioned to face the main tree trunk.  The winter nest is high off the ground in a tree hollow, lined with   vegetation.  Normally, the first brood is had in the tree cavity with the   second brood in a leaf nest.
Tracks:   Has five toes on hind feet (2 5/8" l x 1 1/4" w) and four on the   front feet ( 2" l x 3/8" w).  Straddle   is 4 to 5". Running stride of 16 - 36".  Front and rear tracks   are often lined like a square, so it can give the appearance of two question   marks (!!), with the front tracks behind the rear tracks (or somewhat behind   and between the rear tracks) .
Scat: Pea-sized droppings (1/4 ï¿½   3/8ï¿½ x 3/16ï¿½).
Remarks:   Can be blonde, black (melanistic), erythristic (reddish), or albinos (Olney,   IL is famous for its protected albinos - Trenton, NJ and Greenwood, SC also   have albino populations). Black squirrels are more common in   the northern portions of their range.  Gray   squirrels from MD and the western parts of VA and NC are slightly darker and   larger than those from eastern VA and most of the Carolinas. It is common for   one of the color variants to be dominant in an urban setting, since the   predatory natural selection (culling out) of these colored aberrants does not   exist.
Melanistic   gray squirrels of the Washington DC area owe their existence to two shipments   of black squirrels from Ontario being released in the National Zoological Park   in 1906.  It appears that the dark   pelage gives them an advantage over the gray winter coats of the normal   squirrels in winter through energy savings due to the additional absorbed   solar heat (lower heat loss and lower basal metabolic rates).
Formerly   known to make massive movements in search of food.  Ernest Thompson Seton estimated one mass movement at more   than one billion individuals in 1920.   Such migrations are necessitated by local high populations and erratic   annual acorn mast crops.  A more   recent mass movements on a reduced scale was reported in October of 1968 in the southern   Appalachians of TN, GE and NC.  This followed a   mast crop the previous year, resulting in  an abundance of young squirrels.  Unfortunately,   1968 was a poor mast year, resulting in a major food shortage.   Such a phenomenon is incorrectly called a migration, when it actually   is nothing more than a big fall reshuffle.
Caching of seeds and nuts ensure tree generation. Nuts are buried   separately, about 1/4" to an inch deep and are recovered by any squirrel that may   smell them (one study found 85% of buried nuts were found over the winter). Nuts buried by scientists were recovered at the same rate as nuts buried by the squirrels, indicating that memory is not involved in nut recovery.  The nuts can be smelled when buried under a foot of snow.  A   thicker pelage and layer of fat help insulate the squirrel in winter. While   fox squirrels and gray squirrels inhabit similar habitats and share common   foods, they are rarely found in the same area (mutually exclusive, or   allopatric) and do not interbreed. Fox squirrels prefer the more open woods,   the gray squirrels in the more dense woods. When 10% of the land is wooded,   both species seem to be equally abundant.  When 70% of the land is wooded, fox squirrels are absent.  Gray squirrels are a major prey species of timber rattlesnakes. In the   late summer, swellings under the skin are signs of the developing larvae of   the parasitic botfly, which emerges in the fall. They do not seriously   endanger the squirrel. 
Due   to the extraordinary amount of tannins in their systems afforded the gray and   fox squirrels by their acorn digestion, they are unusual in rarely having   either tapeworms or roundworms, which is a deadly poison to these parasites.
 
Much   more abundant a century ago.  Gypsy   moth defoliation and subsequent loss of acorns in the 1980's practically wiped   out squirrel populations in southern PA.  Important   game species with 40 million "harvested" each year in the US.  In   Kentucky, an average of 1,309,000 gray and fox squirrels were taken annually   from 1964 to 1971.
There   are seven species of the genus Sciurus in North America.
EASTERN FOX SQUIRREL (Sciurus   niger) (shadow tail; dark)
Appalachian   Region Distribution:   Throughout.  
Continental Range: East of the   Great Plains and from PA south.  The   range extends slightly farther west than that of the gray squirrel but not as   far northward.  W/H says to the west   of a line from Harrisburg PA, Harpers Ferry WV, Roanoke VA, and along the Blue   Ridge to the Smokies, with a disjunct subspecies found on the eastern shore,   although other sources show  the fox squirrel ranging throughout all SE   US.  However, declining populations   are found in the piedmont and coastal plains regions of both Virginia and   North Carolina.  Eight   subspecies recognized in the eastern US,   with two subspecies found in the study area.. (The well-known federally-designated endangered species, the Delmarva fox   squirrel; Sciurus niger cinereus, is one of these eight subspecies.  It   is only found on the Delmarva peninsula of Virginia and Maryland.)
Abundance: Uncommon in central   PA and the piedmont and mainland coastal plain of VA and NC, common to the   west of these locations, but with declining numbers.  Due to the decrease in the open, mature forest habitat in the east   preferred by fox squirrels, their numbers are declining and often confined to   small and shrinking localities.
Population Density: Highly   variable.  Reported densities of 0.4 -   2/acre, up to   nearly 10 per acre.  Weigl, working with piedmont and coastal plain   populations in North   Carolina, found densities averaging 0.002/acre.  
Size and Molt: Head and body 10 to   15 inches; 1 ï¿½ - 3 pounds.  (Weigl's   NC piedmont and coastal plain populations averaged 2.2 lbs.)  Sexes are alike in size and color.  Largest   tree squirrel in the Western Hemisphere.   Chapman and Feldhamer   says two molts, with one tail molt.  Nowak says there are two   molts per year in some,  perhaps all, species (of the scuirus genus), but   the tail fur is shed only once yearly.  W/H, PA Mammals, says one molt in late spring.  Twice the size of   gray squirrels.
Mammae: Four pair.
Habitat: Fox squirrels prefer   higher ground and larger trees than gray squirrels.  Open hardwood forests and pine woods where occasional fires promote   grassy surface growth are ideal. Will not be found in the closed forests of   the gray squirrel.
Active Period: Crepuscular in   summer, diurnal in winter; non-hibernating, they start foraging later in the   morning than gray squirrels. Tends to aestivate (summer dormancy) in summer if   hot.  Most active in summer in   light rain or just after rains (cooler temperatures, nuts and fungi are easier   to smell, and the ground is easier to dig).  Most active in September and early October, burying acorns.  Additionally, fox and gray squirrels frequently move to new locations   at this time.  This dispersal   period is also referred to as the ï¿½fall reshuffleï¿½, with movement of over   6 or more miles.  However, mass movements by fox squirrels have never   been as massive as gray squirrels.
Diet: No apparent difference is   observed between the gray and fox squirrels.  Preference is for hickory and oak acorns.  Pine seeds from cones; green or mature and the cambium tree   layer are preferred in some habitats. Also buds and berries, fungi, insects,   bird eggs, and corn.  Nuts and   seeds are buried individually or two or three together like gray squirrels,   versus the caching done by red squirrels.  Early summer may be the hardest time for fox squirrels to find food,   especially in pine forests.  The   buds, flowers and young fruits of tulip trees are heavily foraged when   available.  Studies on recovery of   cached acorns reveal tremendous range from 33% to 99%.  Succulent vegetation will normally satisfy their moisture requirements. Water is utilized if present, but the lack of it   is not a limiting factor.
Home Range: Varies by densities,   food supplies, and habitat quality.  7   - 24 acres and greater are commonly reported.  Weigl's NC piedmont and coastal plains populations had home ranges estimates   of 66 and 42 acres, or 107 and 62 acres, respectively for males and   females.  A study of a Florida population revealed a home range of   106 and 41 acres for males and females.  This is larger than the gray squirrel,   not just due to size, but also the relative paucity of food in the preferred   more open woods habitat.  Home   range may overlap.
Social Structure: Solitary, except   occasionally to feed in common areas and share winter dens among family   members.
Life Cycle: Similar to gray   squirrels (but breeds slightly earlier), with two litters (from two year olds)   with an average of two or three (1-6) per litter per year. (Weigl's NC   piedmont and coastal plain populations revealed no evidence of two litters per   year.)  If  a female produces 2 litters per year, they may produce none the next year if food conditions are bad.  Birthing usually occurs   in  March and again in July, although pregnant   females have been found every month of the year.  Weaned, able to eat solid food in eight weeks, and soon   thereafter are independent.  Gestation   of 44 days.  Sexual maturity in   one year (first year females usually having only one brood).  Will   disperse a distance of 9 miles or more from their birthing site.  Life span up to   12 years.
Dens/Nest: Prefers hollows in trees for   winter and natal nests, but will make large leaf nests in summer (and winter   if tree cavities are scarce). Cavity openings are 3 inches wide with a hollow   of six inches wide by sixteen inches deep. Outside leaf nests vary greatly,   averaging 20 inches in diameter. Like gray squirrels, the opening faces the   trunk. Winter nests have an outer layer of twigs with leaves attached, a   series of inner layers of damp leaves pressed together, with a lining of   shredded bark and leaf fragments.  A   leaf nest may be used for several years.  Fox squirrels average about three to six active leaf nests per   individual (one study reported in Nowak found an average of nine nests were   used per year).  Platforms, made just   for sitting, are sometimes made.
Tracks: Four-toed front feet are 1   and 1/2" and five-toed rear feet are 2" in length.  While running/hopping, the front foot prints are parallel and behind   the rear feet.  Straddle is 4   1/2" with 2' stride.  Food debris is often found scattered about the   base of a tree used as a feeding perch by fox squirrels.  
Scat: Pea-sized droppings.
Remarks:   Fox squirrels get their common name from their fox-like tails. 
Species name comes from southern   subspecies, which is much darker than other regional populations. 
 
The   populations of the Appalachians and to the west differ from the eastern   populations in being smaller (~2 lbs) and more consistently reddish in   color.  The eastern populations of the piedmont and coastal plains   averaged more like 3 pounds in size and were quite variable in coloration,   being silver, gray, black and gold, often with black masks and with distinct   white marking on the nose, ears, and feet.  Additionally, western   populations inhabited deciduous forests while the eastern populations occupied   mature pine-oak woodlands.  Weigl and others suggest that the   southeastern and western fox squirrel populations evolved in isolation in   separate refugia during the Pleistocene, eventually colonizing different   regions to the north and subsequently establishing variable zones of overlap   and interbreeding.
Fox   squirrels have the widest range of colors of any other mammal.  Fox squirrels can be found in several dorsal (back) color   morphs (subspecies); brown, brownish orange, gray-black, blackish brown, steel   gray, or all black (color variations tend to match local habitat - yellow   midwestern squirrels blend with the yellows of the hickories in fall, black of   southeastern squirrels match periodic burning of the pine forests, etc.- its   just someones' thought). Along the coastal area of Virginia and Delaware (S.   niger cinereus) the population is colored steel gray with no tawny. The   ventral (belly) can also vary from creamy yellow to rusty orange to black.  Fox   squirrels have a darker head (than gray squirrels), some white on the muzzle   and white on the back of the ears, and a larger, more fluffy tail than the   gray squirrel.
More   terrestrial than gray squirrels (less agile in trees than gray squirrels).  Fox squirrels spend more time foraging and running about on the ground   than do gray squirrels and will more often run on the ground between trees   while grays will jump from one tree branch to another tree branch.  Wilson says fox squirrels are more ï¿½easy goingï¿½, getting up later   in the morning and turning in earlier in the evening.  Fox squirrels have home ranges of up to ten times the size of grays,   due to the more open (poorer food supply) habitat.
Fox   squirrel bones are pink (due to the accumulation of porphyrin compounds); gray   squirrel bones are white. Of the three tree squirrels, the fox is the   quietest, the gray more vocal, the red squirrel, the most vocal. Mass   movements, well-documented among gray squirrels, are not common, nor as large,   among the fox squirrels.
Due   to the extraordinary amount of tannins in their systems afforded the gray and   fox squirrels by their acorn digestion, which is a deadly poison to tapeworms or   roundworms, they are unusual in rarely having   either of these parasites.
An   account by Seton (1953) states; Arlington   Cemetery had always been a haven of fox-squirrels.  About 20 years ago, they had increased to surprising numbers.  Then one day, they seemed to be possessed of a migration craze; they   all set out eastward.  At once,   they were met by the broad Potomac; but plunged in, swimming away toward   Analostan Island (Roosevelt Island), the nearest wooded tract.  Here many of them stayed; but many moved on, and were lost sight of.  They still frequent Arlington Cemetery.
Approximately   18 Fox-squirrels   were released in the National Zoological Park from 1899 to 1916 from various   states across the country (see remarks for gray squirrels above).
 
When Audubon and Bachman were conducting their research   for the Quadrapeds   of North America , they noted that in South Carolina the fox squirrel "takes possession of the deserted hole of the ivory-billed   woodpecker."
In   Kentucky, an average of 1,309,000 gray and fox squirrels were taken annually   from 1964 to 1971.
There   are five species of the genus Sciurus in North America.
RED SQUIRREL (Tamiasciurus hudsonicus) (steward, shade tail; the Hudson Bay)
Appalachian   Region Distribution:   Throughout.
Continental Range: A boreal   species of the north across Canada, south along the Rockies to southern   Arizona and New Mexico, and down the Appalachians to Smokies.  Five subspecies recognized in   eastern US,   with two found in the study area.  In fact, one of   the widest distributions of any North American squirrel.
Abundance: Common, especially in   conifer forests.
Population Density: 1-3 / acre. W/H   says up to18 per acre with great seasonal variability.  Wilson notes up to 17 ï¿½ 20 per acre is possible in good habitat.  Nowak reports   from 2 - 11 per acre.  Population densities reach a high every three to   four years in the Adirondacks of New York.
Size and Molt: Head and body 7 to 9   inches; 5 to 9 oz.  No differences in size or color by sex.  Two molts,   although, the tail only molts once in the middle of summer.  
Mammae: Four pair.
Habitat: Highly arboreal.  Apparently, it originated in coniferous forests, but now is found also   in mixed hardwood forests and swamps of higher elevations.  In southern limits of its range (southern Appalachians), the red   squirrel is found in the same areas as gray and fox squirrels, with resultant   competition for food and den sites.
Active Period: Diurnal in winter,   crepuscular in summer, spending much time on the ground as well as arboreally;   year-around.  Red squirrels do not hibernate, but may spend several days   in their dens during inclement winter weather. 
Diet: Quite diverse diet (more   omnivorous than the gray squirrel).  Due   to high metabolism, a high energy content diet is required.  Some brown fat is present in winter.  Most of the energy is derived from the hemlock, pine and other conifer   cones, which are stored in mass food caches ("middens") if not eaten on the spot.  Also acorns, hickory and   beechnuts, tulip tree and sycamore seeds, when seasonally available, buds,   twigs, occasional insects and mushrooms (including the very poisonous amanita;   aka, destroying angel or fly agaric).  In   the Smokies, fruits of the cucumber magnolia, mountain holly, silverbell,   beech, buckeye, serviceberry, black walnut, American chestnut, and blackberry;   seeds of mountain maples, hemlock, and pines; cones of fir and spruce;   mushrooms; the buds of the rosebay rhododendron and the buckeye and roadside   garbage cans are eaten.  Fungi are   cut and placed in trees to dry for later winter eating, or later cached in   middens.  Terminal evergreen buds are a main stay in winter diets.  Have been known to eat young birds and bird eggs.  Unlike the single nut burial philosophy of the gray and fox squirrels,   the red squirrel goes for middens, used for   winter food, which is vigorously defended. These middens (made up primarily of   pine cones) may grow over the years to amass several bushels of nuts. Red   squirrels can afford to make this middens where they only have other red   squirrels to defend against.  However,   in regions cohabited with gray squirrels, red squirrels must scatter their   hordes, since gray squirrels are not intimidated by red squirrelsï¿½ threats.  Hole eaten into nut is irregular in shape.  They have favorite feeding sites, as opposed to gray   squirrels, that pretty much eat their acorns where they find them.  The size of this debris pile is measured in bushels and varies with conifer species, seeds, proportion of diet, forest age, squirrel population and the feeding place,   but can be up to 20 feet by 12 feet and 3 feet deep.  Red squirrels are also known to "tap" maple trees for sap. 
Home Range:  2 - 5 acres, with no overlap of range (unlike   gray squirrels), but only 0.5 to 3 acres defended in   the area of the nest and prime feeding areas.  In high quality habitat, red squirrels have been observed to be   non-territorial.  
Social Structure: Solitary. Very   territorial and aggressive in protecting their core home range (1/2 to 2   acres), especially in late summer when juveniles are dispersing.  Females allow   males into their territories in late winter for mating.  Not known for communal denning in winter like gray squirrels. 
Life Cycle:  One or two litters per   year (April - May) with an average of five or six (1-7) per litter. Females are   receptive for only one day, at which time, she allows males to enter her   territory.  Gestation period of 35   days.  A second litter is had in August in good seasons. Weaning at 9 - 11 weeks   of age (W/H says 6 to 7 weeks, Novak says 7 - 8 weeks). (PA mammals says weaning occurs after the   female makes a nest on the periphery of her range for her young. W/H says the   female is known to occasionally leave the area to the young, who then   subdivide it.)  Spring young disperse at   around 18 weeks (September).   Second brood   overwinters with the mother. Young are sexually mature the following season.  Life span two or   three years common, with ten years known in captivity.  Only 5% of a   cohort live beyond five years.
Dens/Nest: A winter and summer nest is   common.  Tree cavities are preferred for winter nests, while leaf nests   (~15 feet high) in summer are common (about the size of a basketball, often   made of grapevine bark, while gray   squirrel nests are larger and coarser), especially in conifer woods, where   cavities are less numerous.  Will also   build on abandoned bird nests or make use of underground dens.  Often, a   second winter nest is made in the form of a weather-tight structure located in   the densest foliage of a tree.  Can   tunnel and make nests in the ground under rocks or stumps in the winter. Burrow holes are 2 ï¿½ to 3   inches in diameter, often with cone remains near the entrance.
Tracks: Four front toes (1/2" l x 3/8" w) and five rear toes (7/8" l x 5/8"w).  Straddle   is 3 to 4".  Running stride   is 9 - 30".  In winter, makes   extensive runways through the snow. 
Scat: Small, 1/4" - 1/2" elongated droppings.
Remarks:   Known in WV as the "fairy diddle".  A northern species, the red squirrel is smaller than the gray squirrel,   with somewhat different summer and winter pelages. In summer, a lateral black   stripe separates the dorsal brown from the white ventral fur. In the winter,   although the black stripe disappears, the back and tail is rusty red and tufts   of hair appear on the ears. Red squirrels are distinctly darker on the head   and sides in the spruce and fir forests of the higher southern Allegheny   Mountains.  Both albinism and melanism is   known among red squirrels.  Very vocal and active;   usually heard before seen. Smaller than the gray and fox squirrels. Vocally   protects itï¿½s territory, many hunters have had their hiding place announced   by the red squirrel.  Noted for   its food caches, which may accumulate in size over several years, usually   located in hollow trees. The seed caches (middens) are favorite sources of   high quality seed used by foresters, which are cleaned and used in nursery   propagation.
 
Hickory   nuts eaten by red squirrels will have a ragged hole opening.  Flying   squirrels have smooth edges of the opening, while white-footed and deer mice   will have several openings.  Gray and fox squirrels crush the nut.
The   western Douglas squirrel is the only other species of this genus in North   America.  Both species are known as pine squirrel, mountain boomer,   chickaree, or fairydiddle.
Several   million red squirrels are trapped each year for the fur trade.
 
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NORTHERN FLYING SQUIRREL (Glaucomys sabrinus) (gray, mouse;   Severn River)
Appalachian   Region Distribution:   High elevations (> 2,680') of the Appalachian Mtns. as far south as the Smokies. Can be   found continuously from Maine to central PA.  South of central PA, only two disjunct relic populations exists.  Both, by their isolation, are recognized as   subspecies and designated as Federally listed Endangered Species.  In six eastern WV counties (Greenbrier, Pendleton, Pocahontas,   Randolph, Tucker and Webster) and Highland County, VA, the subspecies Glaucomys   sabrinus fuscus was first described in 1936.  The type locality is Mill Point, Cranberry River, Pocahontas County.  The second subspecies, Glaucomys   sabrinus coloratus, first described in 1953, is found in SW Virginia near Mount   Rogers, VA (Whitetop Mountain) and along the Appalachian Mountains of the   North Carolina/Tennessee border through the Smokies as far south as   Georgia.   Populations identified   for study by Weigl included Roan Mountain, Bald Knob Ridge, Grandfather   Mountain, the Black Mountains (including Craggy Mountains), and the Great   Smoky Mountains, among others.  For the first   time since 1958, three northern flying squirrels were found in the Smokies in   1987 on Clingman's Dome. The type locality is Bald Knob, 5,000 feet south of the summit, Mt.   Mitchell, NC.
Continental   Range: Throughout Canada, extending south along the Rockies and the   Appalachians.  Four   subspecies recognized in eastern US, with the two Endangered Species   mentioned above and a third found in PA making up the population of the Appalachian region. 
Abundance: Becoming rare - listed federally as Endangered in VA, NC and WV.  In WV,  the characteristic spruce-fir and northern hardwood habitat of   the G. s. fuscus subspecies is relatively abundant, potentially more   continuous and at lower elevations, thus suggesting some potential for   sustained populations.  The subspecies G. s. coloratus, resides   only on high elevation ridges and peaks, and thus occupies habitat islands   which are both highly disjunct and of limited size.   It is very limited from southern Virginia to the Smokies due to the more   aggressive southern flying squirrel (and, to some degree, a parasite that is   transmitted by the southern flying squirrel).  This limited range, along with the possible impact of warming trends, recent   droughts and high elevation loss of conifers from introduced insects and   acid-rain impacts, suggests a more vulnerable status of this southern   subspecies.   These disjunct populations are relics of former   broader populations that existed in historically cooler climatic conditions.  Populations have been shown to fluctuate, with peaks reached in the late   1980's in areas studied in WV, VA and NC.
Population Density: <1 to 4/acre.
Size and Molt: Head and body 5   ï¿½ to 6 2/5 inches; 2 - 4 ï¿½ oz. (Weigl's study populations in NC and TN had a mean head and body length of   6" and weight of  3.85 oz.  These are the subspecies G. s.   coloratus.)  Females are generally larger than males.  The   northern flying squirrel is slightly   larger than the southern flying squirrel. (In addition, the northern subspecies, G.   s fuscus, is smaller with a more muted pelage than the southern   subspecies, G. s. coloratus.  One   molt.  Shedd says two molts, unlike the southern flying squirrel.  Shedd also says the northernï¿½s tail molts only once, like the gray,   red and southern flying squirrel.  
Mammae: Four pair.
Habitat: In the southern   Appalachians, a mixed ecotone of dense coniferous forests and northern hardwood   forests (birch/beech/maple/cherry) are favored habitat.  The WV   subspecies (G. s. fuscus) is generally limited to habitat over 3,000',   while the more southern G. s. coloratus is most commonly found at   elevations over 4,500'.  Habitat in this Appalachian region is limited by   extent of  spruce forests and competition with the   southern flying squirrel.  See remarks below.
Active Period: Nocturnal, primarily   in the evening and just before sunrise. Active year-round.  It is known to withstand cold and wet conditions lethal to red squirrels and   southern flying squirrels.  Has been found foraging on the forest floor even to -24 ï¿½ F (Weigl reports -4ï¿½ F).  However,   Weigl found that when inactive and exposed to cold temperatures, the northern   flying squirrel will drop it's temperature from ~98 to 86ï¿½ F and assume a   curled position.  Red squirrels under similar conditions are not able to   reduce their body temperatures, and thus are not able to survive similar   conditions without adequate store.  Southern flying squirrels show an   intermediate response, with a slightly reduced metabolism and body   temperature.  Weigl notes this reduced metabolism and body temperature is   not torpor, since the northern flying squirrel is capable of immediate   activity at these reduced levels.
Diet: Somewhat more omnivorous than   the southern flying squirrel.  Lichens   and fungi, including mycorrhizal fungi (which is a major source of minerals,   such as sodium and phosphorus, as well as energy), can constitute a major part of their   diet .  The staminate cones of conifers   are a major part of the spring diet.  Nuts are eaten, however,   less so than the southern flying squirrel due to the absence of oaks and   hickories in its range. Also eats buds, fruit, various seeds and a number of   insects (beetles and moths). They are known to raid the middens of nocturnal   red squirrels during the night.  Will   eat meat (young rodents, birds and bird eggs, but less than southern flying   squirrel); are known for stealing bait. Creation of food caches in the summer   for winter use is contradicted by various authors (as a minimum, the behavior   is not as common as with the southern flying squirrel).  It has been   found that many of the mycorrhizal forms of fungi that provide food for the   forest trees, depend on the dispersal of fungal spores through the defecation   of these squirrels.  In fact,  a northern California study   correlated the fungal biomass positively with the numbers of northern flying   squirrels.
Home Range: 2 ï¿½ - 7 ï¿½ acres. (W/H   says 5 - 19 acres or more.) One North Carolina/ Pennsylvania study   reported a home range of about 5 acres.  Weigl's North Carolina work   found ten squirrels had a mean of 23 acres, with a winter range of 29 acres   and a summer range of 15 acres, possibly a function of remote conifer food   sources and mate-finding scenarios.
Social Structure: Very gregarious,   although not as much so as the southern flying squirrel.  Weigl's study found 33 instances of nest sharing, averaging 2.8 per   nest (2-6).  Most groups consisted of   only two individuals (13 out of 33) and 15 groups were composed of adults of   both sexes.  About equal numbers of all male or all females groups (7 and   4 respectively) were observed.  In groups of three or more involving   juveniles, the adult was always a female.  Males do not help in child care.
Life Cycle: Usually one litter with   two or four (1-6) per litter per year.  Parturition from April through September, after a gestation period of 37 - 40 days. Weaned   in eight to nine weeks, often spending the first winter with the mother,   normally breeding the following spring.  Life   span 3 to 5 years, with 13-14 years in captivity.
Den/Nest: Prefers woodpecker holes or   tree cavities, although even witchï¿½s brooms and mats of moss have been used   in northern regions.  Will also use leaf nests (dreys) in spruce trees.  (Being larger than the southern flying squirrel, it must make more   leaf nests, since less suitable trees can be found.)  Also uses old crow or red squirrel nests.   Weigl found 12 summer nests included 7 cavities and 5 dreys, with 27 winter   nests including 15 cavities and 12 dreys.  Urban (1988) found an almost   exclusive reliance on drey nests in WV.  Nests are covered with   firmly matted spruce twigs, lined with shredded yellow birch bark, lichens, grasses,   sedges, and moss.  Outside nests   are 8" - 10" in diameter, and 6" - 8" deep, usually high   (14-28') in red spruce (exclusively spruce for Weigl's study).  A single   2" opening leads to the nest.  Weigl found an average of 3.25 nests per squirrel were used.  70% of   Weigl's nests were found within 300' of the coniferous/hardwood borders.  A third category of nest is recognized as a retreat nest, of marginal nest quality and   serving as sheltered breeding stations, food storage areas or defecatoria.
Tracks: The give away is the "sitzmark", or landing spot, with the pattern of feet leaving the   site, much like a gray squirrel, only smaller (rear foot 1 5/8" in   length, with a straddle of 3 3/4 inches).
Scat: Indistinct piles, each   dropping less than 1/4" in length.
Remarks:   The northern and southern flying squirrels are the only two species in the   genus.  The northern flying squirrel is much larger and heavily built than the southern flying squirrel. Belly hairs   basically white with gray at the base (but occasionally white throughout),   while the southern flying squirrel belly hairs are a solid white.  Individuals from the southern Appalachians tend to be darker than northern   individuals. Mean average glide is 66 feet, although flights up to 270 feet   are recorded (the distance is more a function of height; the glide course is   about three horizontal feet for every vertical foot drop).  Their tail allows them a good deal of maneuverability.  In fact, flying squirrels have been observed turning more than 180ï¿½ during a glide.   Less vocal   than the southern flying squirrel.  
The   northern and southern flying squirrel are generally not sympatric (occurring in the same area;   thus, they are allopatric); the smaller southern flying squirrel being more   aggressive and tending to displace the larger northern flying squirrel.  Where they overlap, populations of both are limited and unstable.  Overlap areas generally support one species or the other.  However, where   there are good populations of the northern flying squirrel, red squirrel   populations are almost always abundant.   There is also evidence of a nematode parasite of the southern flying squirrel   that is lethal or debilitating to the northern flying squirrel.  When   northern flying squirrels come down from their mountain habitats and come into   contact with the southern flying squirrel, it would very likely pick up the   parasite and perhaps suffer either sickness or at least a competitive   disadvantage.  On the other hand, when southern flying squirrel   populations invade the spruce forest habitats of the northern flying squirrel,   it cannot store adequate winter reserves of acorns to enable it to   competitively survive the winters.  Still, another factor comes into play   regarding the nematode.  The staminate spruce cones that make up a   significant portion of the northern flying squirrel's spring diet are filled   with highly aromatic oils that are known to have some potential as "vermifuges".  It is possible that these cones provide the northern flying squirrel with some   protection in the high elevation spruce forests which is lost when it leaves   the coniferous forests for the lower elevation oak forests.  Interestingly, it has also been found that the success of the nematode is   severely limited at colder temperatures.
With   southern flying squirrels found at the highest elevations in Virginia, it does   not look good for the future of the northern flying squirrel in   Virginia.  
The introduced balsam   wooly adelgid will have a major impact on these squirrels by the loss of the   nesting sites and food source.  High   concentrations of heavy metals found at high elevations in NC (lead, copper,   zinc, manganese) can also be harmful to these squirrels.
At   night, the eyes of the flying squirrel will shine red by the light of a   flashlight.
SOUTHERN   FLYING SQUIRREL (Glaucomys volans) (gray, mouse;   flying)
Appalachian   Region Distribution:   Throughout.
Continental Range: All of eastern US.  Three eastern subspecies recognized in eastern US, with   only one in the Appalachian region.
Abundance: Common wherever there   are oak/hickory forests.  In fact,   often outnumbers the diurnal gray squirrel in mature woodlands. 
Population Density: 1-3/acre, up to   5/acre.     
Size and Molt: Head   and body 5 ï¿½ to 5 2/3 inches; 1 - 3 oz. One fall molt.  Females are generally larger than   males.  Smaller than the   northern flying squirrel.    
Mammae: Four pair.
Habitat: Prefers mature hardwood   forests, as opposed to the preferred coniferous forest of the northern flying   squirrel, since they rely on stored middens of acorns, unlike the northern   flying squirrel.
Active Period: Nocturnal. Does not   hibernate, but undergoes periods of torpor and inactivity, more often than the northern flying   squirrel (who, apparently, is more used to the cold weather). NAS says body   temperatures can drop to 22ï¿½F and will take up to 40 minutes to wake.  Tends to aggregate in winter nests (in one study of 841 winter   nests, 676 - 81% - had two or more in the nest, and, of those, 79% housed only   adults).  16 were found curled   together in a wood duck box one February day at the Patuxent Research Refuge   in Maryland (50 have been recorded in one nest).  Low body temperatures seem to coincide with larger denning numbers.
Diet: Most carnivorous member of   the squirrel family; eating insects, birds, eggs, small mice and shrews, and   even carrion. Animal sources dominate summer diet. Winter and spring diet   includes buds, catkins, and shoots of trees.  Also mushrooms, berries, buds and maple sap. Forages mainly arboreally.   Known to cache food (unlike the scurids, this squirrel hides its nuts above   ground in tree hollows. The southern flying squirrel may store up to 15,000   nuts in a season.  Hole eaten in nut is circular with a smooth edge. (It   is a single hole versus numerous smaller holes of the mouse.)
Home Range: 1 - 7 acres.  Females are territorial in summer.  Males are less territorial, with broadly overlapping ranges.  A   Maryland study a home range of 6 acres for males, 5 acres for females and 1.5   acres for juveniles.   Ranges of males overlapped extensively, with   females overlapping very little with other females or males.  
Social Structure: Somewhat   gregarious, especially in winter nests.  Very   shy.  Males overlap ranges extensively, but females ranges overlapped   little among themselves or with male ranges during the breeding   period.   Reports vary on male role in rearing young; one says they help raise   young, SE Mammals says male kicked out at child birth; raised by the mother,   then male reappears for second mating when young are weaned, others make no   comment about male role. Gregarious in winter months, with usually three to   eight sleeping in the same cavity (although 28 and 50 ï¿½ in an Illinois tree   hollow - have been recorded).   Shedd   states the southern flying squirrel is considerably more aggressive than the   northern, and generally is dominant where the two species are sympatric.    
Life   Cycle: Usually two litters, with two to four per litter per year, born in   April and July. Females are polyestrus, in estrus for only one day, with a gestation period of 41 days.  Weaned (and can glide) at eight weeks. Mother and young will stay   together until next litter.  Will   breed in one year (although many studies show summer births often bear young   the following spring). Young females usually have one litter, while older   females often have two litters.  Life   span of three to five years, with records of up to 13 years in captivity.
Dens/Nest: Dependent on cavities in   trees, often  made by woodpeckers (15 - 20 feet above the ground). Has a primary nest   and several secondary nests used intermittently as feeding stations and, even   some for defecating stations, with openings of 1 ï¿½ to 2 inches. Are known to   make summer leaf nests, but being smaller than the northern flying squirrel,   it can more often find a suitable tree cavity.  Nests are lined with lichens or finely chewed bark.  Outside nests are 8" - 10" in diameter.  Known to reuse fox or gray squirrel nests, or even bird houses.
Tracks: The give away is the "sitzmark",   or landing spot, with the pattern of feet leaving the site, much like a gray   squirrel, only smaller (rear foot 1 5/8" in length, with a straddle of   3 3/4 inches).
Scat: Indistinct piles, each   dropping less than 1/4" in length.
Remarks:   A very small tree squirrel with loose skin between the limbs. Belly hairs   totally white, which differentiate the southern from the northern flying   squirrel (whose white belly hairs have a gray base). Extremely arboreal, can glide up to 260 feet (normally at a 30   degree slope), although 30 to 50 feet is more common, and capable of turning   90 degrees in mid-flight. Nut-caching fall habits are photoperiodically   triggered (short days). Those from SC and western NC are darker than those   from MD, VA, and eastern NC. Shy and docile, they make good pets, except they   can be quite noisy at night.
 
Audubon and Bachman reported   seeing at least 200 in and under several large beech and oak trees near   Philadelphia.
At   night, the eyes of the flying squirrel will shine red by the light of a   flashlight.
The   northern and southern flying squirrels are the only two species in the   genus. 
BACK TO THE TOP OF RODENTS
Family   Castoridae ï¿½ Beaver
With   only two species worldwide, this is truly a small family.  The other species, Castor   fiber, is native to portions of Europe and Asia.  Numerous closely related family members existed in   prehistoric times, including the Pleistocene and late Tertiary.  One was a 700 - 800 pound, muskrat-like animal that fed on   marshy vegetation.  Another   extinct group constructed deep, spiraling burrows. 
The   beaver, the only species in North America, is the largest rodent in North   America, weighing 88 pounds, or more. 
Although it is frequently reported that a beaver will continue growing throughout its life, studies indicate that growth basically terminates at age four or five. 
AMERICAN   BEAVER (Castor   canadensis) (beaver; from Canada)
 
Appalachian   Region Distribution:   Throughout, due to restocking. Was basically extirpated from eastern US by the   turn of the century.
Continental Range: All of North America.  Only   one recognized eastern   US subspecies.
Abundance: Becoming more common.
Population Density: Depending on   habitat quality, studies show .2 to   2 colonies/square mile (up to 8/square mile in ideal habitat)  (one colony equals 4-8 individuals), or one   colony per 0.4 - 1.5 miles of stream habitat, up to a maximum of 4.2 per   stream mile.  
Size and Molt: Head and body 25 to   35 inches. The largest rodent in the Appalachian region, weighing 35 to 70 pounds, with a record as of 1981 of 115 pounds.
 
Second   largest rodent in the world, with only the capybara of South America being   larger. While many references state that beaver grow continuously throughout   their life, others say they reach their practical full size after 3 -5   years.  Beaver are somewhat smaller in the southern part of their range.   It can be assumed beaver found in Appalachian streams and rivers will be on   the small size, based on food quality and quantity compared with coastal   marsh/ broad piedmont-coastal plain rivers.  One molt.
Mammae: Two pair.
Habitat: Live along water courses   having adequate tree supply.
Active Period: Nocturnal and   crepuscular, year-round. Most active in the fall to repair the dam and create   a food cache.
Diet: Vegetarian, feeding on the   cambium layer of buds and twigs in winter, aquatic plants and grasses in   summer. A colony of 6 to 8 beaver will consume about 1,000 trees a year.  Known to "mow down" an entire aspen forest before other   trees are eaten.  Coprophagy is   known to occur among beaver.  Beaver   are unable to digest cellulose any better than any other non-ruminant mammal,   thus, large quantities of woody fibrous material must be eaten.  Will cache branches in fall underwater (cache can be ten feet   high and forty feet wide) for winter food, which, in the north, must last for   up to six months.  Caches are not cut until after the sap has returned to   the roots, minimizing chance of spoilage.  In the south, such caches are not made.  In addition, brown fat, stored in the tail, is utilized to provide   needed winter energy.  One study   found witch hazels were cached for food, while maple was eaten on the spot.  Beaver will discriminate among aspen trees, ï¿½testingï¿½ the bark on   aspens, and selecting those individuals with a lower concentration of natural   toxic plant compounds in the bark.
Home Range: Within 660 feet from the lodge.
Social Structure: Monogamous,   gregarious and   very territorial (as a colony).  The social   structure of a beaver colony is based on the mating pair.  Living together in a lodge, beaver live in social units of   about 6, consisting of a mating pair, the yearlings, and the kits (and   occasionally one or more that are about 2.5 years old).  Larger colonies (up to 12 members) are found in higher quality habitat.  Most sources say beaver mate for life (monogamous).  PA mammals says the female is reported to mate for life, although males   are polygynous.  There usually is only a   single breeding female in a colony.  The female appears to be dominant   over both males and young most of the time.  Bonds normally   last only a few years, with the death of one of the mates.  At this time, a member of a younger generation from another colony   replaces the adult.  This   difference in age in the couples is common. It is normally the female that   selects the home site.  If the   paired male dies, the female remains at the existing site.  If the female dies, the territory may be abandoned.  The two-year olds are driven off (or instinctively disperse) a few   miles to establish their own range (one to five miles upstream or downstream), at which time they have reached sexual   maturity. Castor scent mounds are made to stake a claim, which may lead to   territorial fights, or the finding of a unmated beaver of the opposite sex.  Family unit will protect home territory from other beaver, although   more than one family may share a lake.
Life Cycle: Usually only one   litter with three to four per litter per year. Adult females may not   successfully reproduce every year.  Mating   occurs from December through February, with birthing from April through June.  Copulation occurs in the water.  Estrus lasts two weeks, with the female being receptive for 10 to 12   hours.  The gestation period is variously reported to be from 98 to 128 days.  Precocial young, weaned after six weeks (but may last for more than 3   months), live with the parents for two   seasons until forced out prior to the third litter. Highest mortality occurs   at this time. Until young reach 30 days of age, high buoyancy prevents them   from submerging and leaving the den.  Sexual maturity is reached at two or   three years of age. This is an extremely long time for rodents, and may   reflect the learning and experience required prior to setting off on its own.  Life span of 15 is considered maximum, with one reaching 24 in the   wild.  Some beaver in captivity have attained ages of 35 to 50 years in   zoos.
Den/Nest: Lodges are along the bank or   on islands measuring six feet high and 12 to 15 feet in diameter. The inner   chamber is six feet wide by two feet high.  Lodges are added to throughout the lifetime of the beaver and may get   to be eight feet high and forty feet across.  After the major initial construction of the lodge is completed, the beaver   dives underwater and cuts his/`her way into the center of the mass.  When   they are above the waterline, they cut out a chamber that will be 3-4 feet   across and perhaps 18-24' high.  Normally, two levels exist; a lower   level, only 3-5" above the waterline for feeding and preening, and an   upper level, 8-10" higher, used for bedding.  Several entrances into the lodge may exist.  A small air hole, or chimney, is made in the top for   ventilation.  The outside is coated with   mud for insulation, waterproofing and defense in winter (when it freezes rock   hard).  Only the peak of the den is not mud coated, functioning as an air   vent.  Occasionally, a   winter lodge is also constructed, in addition to the summer lodge.  Beaver wonï¿½t make dams in watercourses of adequate depth (or swift   current). Dens will be made in the banks in these circumstances ("bank   beavers"), with burrows as long as 30'.  Occasionally, in   beaver colonies, both lodges and bank dens will be made.  Scent mounds (mud and vegetational debris, 8-10" high   and 10-12" wide) are placed in   piles near the colony territorial boundaries and wetted with urine, castorium,   and perhaps contents of the oil or anal glands.
Tracks: Notice the webbed rear   feet, approximately 6" long by 5" wide, often obscured by the   dragging tail.  Often along   heavily used trails from the body of water into the woods.  Four toes in front and five toes in rear.  The front foot can have a grooming spur on the side so it   looks like five toes in front. Another sign of beaver is the scent mound, or   sign heaps; a   mound of soil about a foot high scented with castoreum marking the beaver's   range.  There may be over a hundred scent mounds throughout the home range.                  
Scat: As noted above, beaver practice coprophagy.  Using microbial action in the caecum, located between the large and   small intestines, to ferment digesting fibrous tissues, a soft green fecal   material is produced, which they reingest.  Another kind of feces, not reingested, is usually excreted in the water   (in fact, it is difficult for beaver to defecate out of water), thus, it is   unlikely to find beaver scat.  They   consist of oval pellets of coarse sawdust-like material, 1 1/4" long by   3/4 inches wide.
Remarks:   Beaver are more specialized for swimming than any other rodent.  When beavers swim, only their head is exposed, while both the head and back are exposed with the muskrat.  On land, a mother can carry her kits on her tail,  or even walk erect and hold them in her forepaws.  Beaver have been observed walking bipedally, carrying a bundle of twigs in their arms. 
Beaver have scent glands (castor glands) at the base of the tail which produce   a bitter, orange-brown secretion known as castoreum, used in the making of   perfumes. Most of the oil is shipped to France or Orient for processing.  The   tail is important in temperature regulation, fat storage, and as a means of   communication.  Rarely, a beaver will be killed by a falling tree cut by the   beaver. When alarmed, beaver will slap the water surface with their tail and   then submerge. Beaver, as well as other rodents, keep their incisors worn down   by grinding their teeth together; not by constantly chewing wood, as is often   believed. In cutting, beaver use their upper front teeth for leverage, the   actual cutting being done only by the lower ones.  The outer surfaces of the large, ever-growing incisors are covered by   an orange layer of enamel, harder than the enamel of most mammalï¿½s teeth   because iron is substituted for some of the calcium.  
 
Beaver   stay underwater for ten to fifteen minutes.  This is due to a metabolism that slows down to half its usual rate   underwater and an extremely efficient oxygen uptake within the beaverï¿½s   lungs, which can use 75% of the available oxygen, versus only 15% of man.
Beaver   tails act to store brown fat as a winter food reserve, a rudder in swimming, a   fifth leg, and as a warning to other beavers of danger by slapping the water   surface.  Interestingly, beaver   ignore the slaps of certain beaver, as they do most juveniles.  Yes, they can distinguish among beaver by their tail slap.
Dams   are made as a means of protection for the beaver (they can hide in the   water).  An average dam will be 5 to7 feet high and 75 feet long.  Many dams will be over 1,000 feet long, with a few reaching over 2,000   feet.  The   record dam, measured in Montana, was 2,154 feet long, or 0.4 mile.
  Dams have been found that are ten feet high in narrow gorges.  When all   of the nearby trees have been cut, the beaver will make canals reaching up to   100 feet.  They not only facilitate food gathering but also allow the   beavers to escape from predators.  The stimulus for bu
ilding dams seems to come from the sound of   running water.
It   can be reasonably stated that the beaver trade allowed the settlement of North   America.  Although nearly   extirpated in the eastern US, E. T. Seton suggests that there were as many as   60,000,000 beaver in pre-colonial times in North America.  
Beaver were extirpated in Virginia between 1885 and 1911.  Between 1932 and 1938, 35 were released in nine VA counties.  By 1943, enough had reproduced that surplus beaver were redistributed   to new areas, with trapping started in 1953. 
 
Beaver   in West Virginia were extirpated by 1923.  It was reintroduced during the   period of 1933 through 1940 in Randolph, Pocahontas, and Tucker   Counties.  Since that time, they have spread throughout the state, though   most conspicuous in the Canaan Valley.
Roughly,   500,000 total pelts have been harvested annually from Canadian and US, based   on reports from 1950 to 1977.  In   the process of trapping beaver, usually one river otter is caught for every 8   to 10 beaver, in addition to mink and raccoon in water sets and bobcat and fox   in land sets. 
In one season, (1976/77),  45 states in the US recorded a total harvest of 232,710 pelts.  During the 1983/84 season in Canada, 341,354 pelts were taken.
Due   to the increase in beavers in northeastern US, the moose population has also   increased, benefited by the ponds made by the beaver.  Other species benefiting from the beaverï¿½s operations   include muskrat, otters, fish, waterfowl, cavity-nesting birds, amphibians and   reptiles.  Once all the trees   within 300 to 600 feet to the dam are cut, the beaver move.  Even after the beaver leave, the remaining beaver meadow   provides habitat for numerous plants and animals.  Eventually, trees and shrubs revegetate the meadow, and,   ultimately, the beaver come back and the cycle starts over again.
 
 
Family   Muridae - Mice, Rats, Lemmings and Voles
This   family is the largest family of mammals in the world, as well as in the   eastern United States. They make up about 25% of all of the known species of   mammals.  This family includes   many small to medium-sized rodents. Additionally, the larger muskrat is   included in this family. As a whole, the Muridae family is usually nocturnal   and omnivorous, has multiple litters and does not hibernate. They have varying   habitats from arboreal, terrestrial, subterranean to aquatic.   Tails are rarely bushy. Mice and rats have large ears and eyes with long   tails, while lemmings and voles have small ears and eyes with short tails.  Most have four front toes (some five) and all have five back   toes.  Nests are commonly shredded grass and leaves forming   a 6 to 8 inch diameter sphere.
 
Mice and voles have four front toes and five hind toes approximately ï¿½   to 3/8" wide. Vole trails are wider than shrews, averaging 1 ï¿½" wide, often without a tail track, as is common with shrews. Both shrews and   voles tunnel in snow.  Mice generally do not tunnel and can be identified by   their galloping trail, which resembles a small squirrel, with sets of prints   (often including tail print) a few inches to a few feet apart.  Entrance holes   are generally 1 ï¿½" in diameter.  Mice generally use holes and tunnels   made by voles and moles.
The   Muridae family is subdivided into three subfamilies; the Arvicolinae,   Sigmodontinae, and the Murinae. 
The   Arvicolinae subfamily includes voles, lemmings and muskrats.  These rodents tend to be compact, short-tailed, round-headed creatures.  Originating 70 million years ago, it wasnï¿½t until the recent   Pleistocene epoch (1 million years ago)  that   they exploded in their speciation.  Voles   and lemmings are the dominant small mammals of the far north and provide the   major food source for predatory mammals.  They have extremely high reproductive   rates, exhibit post-partum estrus, quick sexual maturity, and short   pregnancies.  Most have 8 mammary   glands.  Such factors have   combined to enable one meadow vole to have 17 litters in one year with 83   offspring and 78 grandchildren before her first birthday.  Of course, in nature, high fecundity must be reflected in high mortality.  The average life expectancy of the meadow vole is one month, with one year being reached only   in ideal conditions.  They also exhibit population fluctuations ranging from 1 to   1,000ï¿½s per acre in a three or four year cycle.  They are all herbivores, benefiting from having grinding   teeth and a enlarged intestinal chamber for fermenting the low-value foods.  Many practice coprophagy.  Voles   and lemming do not drink water, but gather it through the vegetation. 
The   Sigmodontinae include white-footed and deer mice, harvest mice and wood rats. 
The   third subfamily, the Murinae, include the introduced house mouse and two   introduced rats.
 
Although there is no biological difference between rats and mice, rats are generally larger.
World-wide,   the Muridae includes 281 genera and 1,326 species. 
There   are 14 genera and 26 species in the eastern United States, of which 9 genera   and 15 species are represented in the Appalachian region (Jones).
    Subfamily   Sigmodontinae
EASTERN   HARVEST MOUSE (Reithrodontomys   humulis) (groove-toothed mouse; small)
Appalachian   Region Distribution: Extirpated in  Maryland; now found to the south.  
Continental Range: SE US.  Two subspecies have been   recognized in eastern US and in the Appalachian region.
Abundance: Uncommon in mountains. 
Population Densities: Tends to be found in localized populations of 4 ï¿½ 10 per   acre.  One record of 90/acre has been recorded.
Size and Molt: Head and body 2 3/5   to 3 inches; ï¿½ - ï¿½ oz.  Smallest   rodent in the Appalachian region.  One molt.
Mammae: Six
Habitat: Inhabits old fields,   marshes, and wet meadows.   The greatest numbers have been found in broom sedge.  Shares habitat with least shrews, meadow mice, and   golden mice.  Seldom found in   forests.
Active Period: Nocturnal, active   year-round.
Diet: Weed seeds, butterfly and   moth larvae (caterpillars), shoots of vegetation, and some insects. Some caching of   seeds has been identified. 
Home Range: ï¿½ - 1 acre, with male   range being larger than female.
Social Structure: Somewhat   gregarious.  Females protect the   young for the first three weeks (known to pull young back into the nest when   alarmed).  Males are normally not   part of the family unit, making their own nests.
Life   Cycle: Breeding throughout the warmer months, beginning in March.  Three litters averaging two to four (1-8) per litter.  Young can breed at eight to twelve weeks. Gestation period of 21 days.   (One female in captivity had eight litters in 11 months.)  Weaning in two to four weeks.  Life   span usually less than one year.
Nest: A baseball-sized (4") globular   nest, made of shredded grass and plant fiber, either on or just above the   ground in brushy shrubs.  These   single-opening nests are utilized by the harvest mouse year-round, as these   mice do not hibernate.  Occasionally,   a winter nest is located in burrows and small crevices.
Tracks: Youï¿½ve got to be kidding.  Did you see how small this guy is?
  They use runways of other rodents. 
Remarks:   The smallest mouse (and rodent) in the SE and one of the least known mammals.   An excellent climber. Cotton rats and eastern harvest mice occupy similar   habitats, but are not found together, suggesting mutual exclusion (see habitat   above). 
Originally   described by Audubon and Bachman. 
 
WHITE-FOOTED MOUSE (Peromyscus   leucopus) (might be Greek with pero meaning "defective" and   myskos meaning "mouse", or Latin with pero meaning "pointed", or little pouched mouse; white-footed)
Appalachian   Region Distribution:   Throughout.
Continental Range: East of the Rockies and lacking in the SE   piedmont and coastal plain.   Four   subspecies known in eastern US,   with two in the Appalachian region (two on islands, including Martha's Vineyard).
Abundance: Both the   white-footed and the deer mouse, members of the Peromyscus genus, are the   most common rodents in many habitats in the Appalachian mountains.
Population Density: 2-15 per acre.  One study  in Virginia showed a mouse population increase from 1 to   42/acre after a good mast year, only to fall back to 5/acre the next year.
Size and Molt: Head and body 3 3/5   to 4 1/5 inches; ï¿½ - 1 oz. Two   molts. Nowak says one molt.
Mammae: Three pair. Nowak says four   or six.
Habitat: Brushy areas, deep   woodlands or wooded forest   edge areas. Warm, dry hardwood forests rather than cool, moist coniferous   forests.  Also takes up residence   in homes.  Generally found at   lower elevations than deer mice, but large overlap occurs considerably.
Active Period: Principally   nocturnal, with diurnal tendencies in winter.  Non-hibernators.  By   mid-October, mice begin to communally nest in trees.  In mid-winter, communal nests are moved to below ground.  Even during the coldest weather of winter, most white-footed mice   remain active.  Some become   torpid, with body temperature dropping from 96 to 65ï¿½,   and breath rate decreasing from 700 to as few as 60 per minute.  Has been recorded huddling with deer mice. Communal nesting,   nesting below ground, and torpor are all energy-saving adaptations against   cold that can yield an energy savings of nearly 75%.
Diet:   Omnivorous.  During fall and   winter, up to 75% of the diet is made up of arthropods (insects, centipedes,   spiders). Stokes says nuts and seeds, supplemented by over-wintering insects   and leaves/twigs.  Summer diets   include up to 50% seeds and fruit, but insects are still a staple. Is known to   cache food in the fall for winter.  Stokes   says caches food year-round. Rose hips from multiflora roses, cherry pits and jewelweed   seeds (Impatiens) are  favored foods.  Tends   to eat more insects than the deer mouse.  (A Smokies summer study found seeds to comprise 2.2% of the total   volume for the white-footed mouse, while they comprised 57.7% of the deer   mouse summer diet.
Home   Range: 0.2 - 3 acres, with males having larger home ranges. Ranges are   generally larger in summer than winter.  Nowak reports a northern VA   study finding an average home range of 0.25 acres for both sexes, while a   Quebec study found home ranges of 3.15 acres for males and 2.28 acres for   females.  Females   sometimes have the better quality habitat.  When that happens, the female is bigger than the male.  Females are often more aggressive in protecting their territory,   especially when on a nest.  Intruding   females will almost always kill the young of another female.  Males occupy home ranges overlapping those of one or more   females.  Female home ranges overlap male home ranges, but the home ranges are   mutually exclusive within sexes.
Social Structure: Nests may be shared   by pairs or families and for   winter grouping.  Both   sexes share in the child rearing (the males to a lesser, and not clear how   often, extent).  Normally   polygamous, but can be monogamous, and in one case, it appeared to be   polyandrous (one female and several males). Promiscuous.  Females reside in non-overlapping home ranges maintained by mutual   avoidance at low densities, by overt aggression at high densities.  Males occupy home ranges overlapping those of one or more   females, and mate with the included females.  While the male may share the nest with a female, but he is evicted at partus,   perhaps as a protection against infanticide, being allowed to return at a   later date.  Both members of the Peromyscus genera in this Appalachian region behave   territorially as one species; defending their territories against other   animals of either species.  See remarks below. 
Life Cycle: Three to four litters   with an average of four per litter per year (less in the southern range).  Mammals of Virginia presented five-year studies at Mountain Lake, with   an average of 1.4 litters per year.  One   female is known to having given birth to 26 litters over a two year period,   and another; 14 over a twelve month period.  Gestation period of 21 ï¿½ 23 days (up to 37 days when the female is   nursing).  Females are polyestrous, with post-partum heat.  If a female mates while still nursing,   a delayed implantation of the fertilized egg will occur for 2 to 7 days.  Young are weaned in 3-4 weeks, dispersing in another month.  Females can breed in   40 days.  Life   span of 2 - 3 years.  W/H and   Wilson says annual turnover in this species is almost total.  Mammals of Virginia says four to eight months in the wild, with   captives living over five years.         
Nest:   Nests of both the deer mouse and the white-footed mouse are often made from   old bird and squirrel nests in trees. Look in the winter for covered nests.   Often winter nests are made in tree hollows or in the ground.  Entrance holes   are generally 1 ï¿½" in diameter.  Mice generally use holes and tunnels   made by voles and moles.  Will also use abandoned bird houses, especially in winter or to produce   its young. Two studies in Giles County, VA revealed deer mice   preferring nests high in hollow trees, while white-footed mice favored more   variable sites, including ground and underground winter  nests.  When a nest becomes soiled, the mouse will abandon it   and build a new one.
Tracks:  Hindprint 5/8" long with 5 toes; foreprint is 1/4" long and wide with 4 toes.  Straddle is 1 3/8", with foreprints printing behind and between   hindprints (like squirrels).  Mice and voles have four front toes and five hind toes approximately ï¿½   to 3/8" wide. White-footed mice and deer   mice, unlike voles, do not create tunnels through the grasses, nor do they dig   burrows.  However, they will use   the tunnels and burrows of voles and other small mammals if available.
 
Mice can be identified by   their galloping trail, which resembles a small squirrel, with sets of prints   (often including tail print) a few inches to a few feet apart. 
Remarks:   This genus, which includes the white-footed and the below described deer   mouse, are by far the most common of the rodents.  Members of the Peromyscus genus are considered physiological generalists, thus explaining their   ubiquitous nature and variable diet.  The   reproductive characteristics are readily modified in response to environmental   conditions.  Litter size is   greatest in the northern regions.  At   low population densities, most juveniles attained maturation by fall; at high   densities, they often did not.  The   presence of an adult suppresses maturation in juveniles.  This seems to encourage dispersal and certainly reduces in-breeding.  Members of both these species behave territorially as one species,   defending their territories against other animals of either species.  They will be more defensive of their territories at high densities (10 per   acre); especially females.  Good   climbers. One of the first small mammals to colonize reclaimed strip mine   sites and clearcuts. Aka woodland deer mouse, the tail is equal to, or shorter   than, the head and body length and is indistinctly bi-colored. 
The   tail of the white-footed mouse is usually slightly less than half the animal's   body and head length (~75mm).  It is indistinctly two-toned.  The   deer mouse has two forms; the woodland and the prairie form.  Both have a tail that is distinctly   bi-colored, being dark on top.  However, the forest form's tail is longer   than, or equal to it's to body and head (~90mm), while the prairie form's tail   is much less than it's body and head (~50mm).
In the Appalachian region, this species   can easily be confused with the larger, long-tailed forest form of the deer   mouse (see below); both often sympatric (found together).
  
Where the two coexist, the deer mouse is much more apt to climb than the   white-footed mouse.
The   white-footed mouse has a larger and paler race that is normally found in the   southern Appalachians from MD south.
DEER MOUSE (Peromyscus maniculatus) (either Greek with pero meaning "defective" and   myskos meaning "mouse", or Latin with pero meaning "pointed", or little pouched mouse; hand)
Appalachian   Region Distribution:   Throughout.
Continental Range: The most widespread rodent   in North America.  All of North America, except south and east of   the Appalachian region and far north.  Quite   messy regarding the number of subspecies.  As many as 57 subspecies have been recognized in North America.  However,   W/H only recognizes two subspecies in eastern US, with one in the Appalachian   region.  The subspecies of deer mice segregate into two broad categories;   long-tailed, large-eared forest inhabitants and short-tailed, small-eared open   country forms. See remarks below if you're into this sort of thing.
Abundance: One of the most   common mice in the Appalachian mountains, but known for their population   fluctuations.  
Population Density:  Normally from 0.4/acre to 10/acre, with a range up to 36/acre, with some populations   being colonial in winter.  Populations fluctuates in 3 ï¿½ 5 year cycles. 
Size and Molt: Head and body 2 4/5   to 4 inches; 2/3 - 1 ï¿½ oz. Two   molts.  Nowak says one molt.
Mammae: Three pair.  Nowak   says two or three pair.
Habitat: Quite diverse, preferring   woody or brushy areas, also coniferous forests.  Prefers   cool, moist forests and is found most abundantly at the higher altitudes,   while the white-footed mouse tends to occur in greater numbers at the lower   elevations.  In general, favors more   moist habitats than the white-footed mouse.  Nowak says it does not   regularly occur in moist places.  In the Smokies, these   two species come together at about 3000ï¿½.  However, there is considerable overlap.
Active Period: Strictly nocturnal   (versus the diurnal shrews and moles). (Wilson says nocturnal and   crepuscular.)  Active year-round, but enters torpidity   and employs communal nesting (occasionally with white-footed mice) during   winter cold spells.
Diet:  More primarily a seed   eater than the white-footed mouse.  Its diet includes   seeds, fruit, nuts, fungi (Endogone), insects, centipedes, and green vegetation.  Also, insects may make up to about 10 - 20% of their diet.  Makes food caches of nuts and seeds for winter food.  
Home Range: ï¿½ - 3 acres.  W/H says 25,000 to 32,000 square feet, not including the arboreal   dimension.  Males usually have   larger home ranges than do females.  Nowak reports an average home range of 2.5 acres for males and 1.5   acres for females.  Females are often territorial during the breeding season.
Social Structure: Promiscuous.  See remarks for the white-footed mouse.  Usually solitary, except a brief stay after mating, and during cold   weather, where up to 13 individuals have been recorded huddled together.  Nowak reports a Canadian study (Banfield) that considers the deer mouse to be a sociable   mouse, tolerant  of other sexes and ages.  Banfield further finds   the male lives with the family and helps care for the young.
Life Cycle: Litters are three or   four with an average of five (1-9) per litter per year with sexual maturity at six   weeks. Gestation period of 23 - 29 days. Exhibits post-partum estrus. Young   are weaned in 3-4 weeks, dispersing when sexually mature in six weeks.  Life   span of 1.5 to 2 years, although up to 8 years in captivity. 
Den/Nest: Entrance holes   are generally 1 ï¿½" in diameter.  Mice generally use holes and tunnels   made by voles and moles.   4" spheres of grass   lined with down from plants or with shredded materials in trees, stumps, under logs,   stumps and boulders.  As nests are soiled, another nest will be made, so   that several nests are made in the course of a year.  Nests of both the deer mouse and the white-footed mouse are often made from   old bird and squirrel nests in trees. Look in the winter for covered nests.  Two studies in Giles County, VA revealed deer mice   preferring nests high in hollow trees, while white-footed mice favored more   variable sites, including ground and underground winter  nests.
Tracks: Hindprint 5/8" long   with 5 toes; foreprint is 1/4" long and wide with 4 toes.  Straddle   is 1 3/8", with foreprints printing behind and between hindprints (like   squirrels).   Mice and voles have four front toes and five hind toes approximately ï¿½   to 3/8" wide.  Mice can be identified by   their galloping trail, which resembles a small squirrel, with sets of prints   (often including tail print) a few inches to a few feet apart.  When moving rapidly, they   leave two closely spaced pairs of tracks, unlike the trotting gait of shrews   and woodland voles. The tail often leaves a mark in the snow or sand.   White-footed mice and deer mice, unlike voles, do not create tunnels through   the grasses, nor do they dig burrows. However, they will use the tunnels and   burrows of voles and other small mammals if available.
Remarks:  Two   subspecies exist: one (Peromyscus   maniculatus maniculatus) being a   large, long-tailed (equal to the head and body length), big-eared woodland form and the other, (Peromyscus   maniculatus bairdii) a much smaller, short-tailed (much less than half the   total length), small-eared field, or prairie form.
This   presents an interesting example of the difficulty of taxonomic placement.  These two morphological and behavioral types occur together   geographically in large areas of Pennsylvania, New York and Michigan, but in   different habitats.  However, they   apparently intergrade through a series of populations in Wisconsin and   Michigan.  Thus, the overlapping   populations have well-developed secondary isolating mechanisms and are acting   as true species, whereas, the Wisconsin populations are not even separated by   primary isolating mechanisms.  This   situation is called ï¿½circular overlapï¿½.  Quoting from W/H, ï¿½If   the two forms are deemed separate species, then one is in the position of   accepting the fact of intergradation between two ï¿½speciesï¿½ in Wisconsin.  But if they are called separate subspecies of one species, then one has   two ï¿½subspeciesï¿½ occurring together but not breeding.  The latter choice, the more conservative of the two, is generally   accepted.ï¿½ 
In   addition to these two subspecies, there are two ï¿½racesï¿½ in the Appalachian   region within the larger woodland subspecies; one with a longer tail, and one   with a shorter tail. The common race is the long-tailed, found throughout the   Appalachian region. The short-tailed race is a recent immigrant of the MD-VA   coastal plain and piedmont regions. (There are other examples of long-and   short-tailed forms of P. maniculatus , and other examples of circular overlap within this species in the western   US.  In general, the longer tailed   race is the more arboreal. (From what information Iï¿½ve read about these   Peromyscus, it appears there are many more masterï¿½s theses to be had   here.)
Both   subspecies are similar to the white-footed mouse, Peromyscus leucopus, which is essentially intermediate in several   characters between the two.  The   tail in the white-footed mouse, however, is less distinctly bicolored and is   just slightly less than half the total length of the animal.
The   deer mouse is more common at higher elevations than the white-footed mouse.   Range overlaps at 2,000ï¿½ in SNP and 3,000ï¿½ in Smokies.  Where the white-footed and deer mouse are sympatric, the deer mouse is   more apt to be arboreal.
Deer   mice are commonly used as research animals.  
The   first documented case of hantaviruses in North American were diagnosed in May   1993, when several Native Americans died of a respiratory aliment on a   reservation in Arizona.  The first   case east of the Mississippi was confirmed in January 1994, when a man in   Indiana died.  Apparently,   hantavirus had been present nationwide for some time, but had gone   unrecognized.  Hantavirus has been   found in a number of other closely related mice species, including the   white-footed mouse.
The   deer mice and white-footed mice are major hosts in Lyme disease.  The mice are hosts to the larval stage of the tick that carries the   bacterium.
 
Deer   mice may be destructive to forest regeneration due to its propensity to feed   on tree seeds, especially conifer seeds.
Wilson   adds that deer mice are scansorial; meaning being able to climb.  How that differs from arboreal, I donï¿½t know, and frankly, my dearï¿½ 
 
GOLDEN   MOUSE (Ochrotomys   nuttalli)
Appalachian   Region Distribution:   It is found from central Virginia south.                        
Continental Range: Southeastern   and southcentral US.  Four subspecies recognized in eastern US,   with basically only one in the Appalachian region.
Abundance: Common and   localized, especially south of the Appalachian region.
Population Density: Nowak reports 1.25/acre in TN, a range from 1.2 - 17/acre in the   Smokies, and from 4.25 - 185/acre in Illinois.  W/H reports 2.8 to 3.6 per   acre.  
Size and Molt: Head and body 3 2/5   to 3 4/5 inches; 2/3 - 1 oz.  Two molts.
Mammae: Three pair.
Habitat: It is an semi-arboreal   species, often found 30 feet above the ground, running adeptly along narrow   branches.  Found in a variety of   habitats, commonly dominated by greenbriar or honeysuckle.  In the mountainous areas, they occupy the pine and greenbriar thickets,   talus slopes of dense hemlock forests, and on the edges of sedge fields.  They are more common in lowland, heavily forested floodplains with   extensive undergrowth of greenbriar or honeysuckle.
Active Period: Nocturnal to   crepuscular.  Active year-around.
Diet: Omnivorous; preferring seeds   of greenbriar, cherry, sumac, dogwood and insects.  Golden mice have cheek pouches, like chipmunks, and carry their food to   their feeding platforms to eat.
Home Range: W/H says 0.1 to 1.5 acre.  Difficult to compare with other mice, since their arboreal nature adds   a vertical dimension to their range. Home   ranges overlap extensively.
Social Structure: Known to be   gregarious, with as many as eight having been found in the same nest.  In captivity, the male and female remain together until the birth of   the young, at which time the male leaves.  
Life Cycle: Four or five litters   with an average of two to three (1-4) per litter per year, weaned in 21 days, with   sexual maturity at six weeks.  Post-partum   estrus enables an interval of 25 days normally occurring between litters, from   mid-March through October.  One captive female had 17 litters in 18 months.  Gestation period of about 25 days. Life span of two and ï¿½   years (one of longest living of the small rodents).  (W/H says averaging 6 - 7 months.)  One has lived in captivity for eight years five months; the longest   life span recorded for any species of North American rats or mice.  Despite their long life span, they are born more advanced than most   mice, walking on their first day, and hanging upside down by their tail on day   four.
Nest: Makes several summer tree   nests (neat, compact, 5 - 8" globe-shaped balls) 1 to 15 feet above the   ground (NAS says up to 30'),   in greenbriar, honeysuckle, conifer or other trees, covered with grass,   leaves, or   coniferous leaves and lined with finely shredded bark, feathers or fur. These   nests may be formed around abandoned bird nests and may be used by successive   generations for several years.  They construct many   feeding platforms, 5 to 10 feet (or more - Nowak reports 45 feet) above the ground (a ratio of 6   platforms to 1 nest). Makes underground nests in winter and occasionally under   logs and rocks in summer. Larger nests can be home to several mice (as many as   eight have been found in a nest).
Tracks: Its feet are similar in   size to the deer mice.
Remarks:   The golden mouse is the single species in the genus Ochrotomys.  
One of the most beautiful and unique of the native mice.  A medium sized mouse with a striking golden cinnamon or burnt orange   coat.  Those in the Appalachian region are duskier reddish brown in color and   larger than those found in the piedmont.  
An arboreal species, with a prehensile tail, used to wrap around limbs.  Rather docile (easily handled - good   pets). 
Audubon   and Bachman described one subspecies of the golden mouse.
The   golden mouse is abundant in the Dismal Swamp.
APPALACHIAN WOODRAT (Neotoma   magister)(new, sharp: ?)
Appalachian   Region Distribution:   Throughout.
Continental Range: Found from Pennsylvania and south along the   Appalachians to the Smokies; west, throughout the Ohio valley, but lacking in   the eastern coastal plain and piedmont.  No   subspecies described.
Abundance: Disjunct populations   throughout.  Declining in populations, especially in the northern range, being   extirpated in New York in 1987 and most of eastern PA and New Jersey (one site   still extant) and threatened in Pennsylvania, Ohio and Maryland. Recent work indicated that, aside from their apparent   disappearance from Fairfax County along the Potomac, woodrat populations are stable in Virginia. 
Population Density: 1-2 acre.  W/H reports about 70 animals along a 3200 foot bluff in southern Indiana.
Size and Molt: Head and body is 8 -   9 inches; 7 - 12.78 oz.  (W/H  reports an average of 9.48" and 12.95 - 15.93 oz for   ten adults from New York, PA and WV.)   Size decreases in the southern range.
Two molts.
Mammae: Two pair.
Habitat: Much more specific as to   its habitat needs than the eastern woodrat.  Limited to caves, cliffs and   mountainous rocky talus or scree areas (some excellent communal nests are   found on the back side of Old Rag Mountain, VA in the "reflector oven   cave").  Known   to be arboreal. The presence of eastern red cedars seem particularly   beneficial to them.  They need dense cover, and occur in upland and lowland forest, old fields, grass and woodland edge, hedgerows, cliffs and   ledges. Herbaceous ground vegetation less than 40% is preferred 
Active Period: Nocturnal. Active   all year.  Cave residents seem to   be more active during the daylight hours. 
Diet: Predominantly vegetarians,   feeding almost entirely on vegetation (very few insects, unlike white-footed   and deer mice). Caches food (twigs and mushrooms) in the fall.
Home Range: 100 square yards.
Social Structure: Varied reports.  Primarily solitary, although some references indicate a colonial   nature.  W/H says aggressive among   themselves, although referenced one study that found aggressive solitary   dominant wood rats and communal subordinants.
Life Cycle: Females have two or   three litters (or even four ï¿½ depending on weather and food availability)   from March to September, averaging two (1-4) per litter per year (much less   prolific than most rodents). Altricial young. Gestation period of 35 days.   Young are weaned in two to three weeks, and can breed at eight weeks, but most   don't breed until their second season.  Life span of two to four years.
Den/Nest: The nest is a bulky,   football-sized, cup-like structure built of shredded bark and grasses,   surrounded by a conspicuous pile (protective?) of sticks, twigs and debris, in, and among, protected   rocks, open on top, like bird nests.  Unlike the eastern wood rat (see Remarks   below), the Appalachian wood rat almost never builds stick houses that shelter   a nest.  Rather, the nest site is often "barricaded" with piles   of sticks or other items that may provide an element of protection.  Arboreal nests are   known in areas of seasonal high water.   Midden mounds are common (normally made in the fall as food caches),   as are debris piles, consisting of sticks, bark, bones, dung of other animals,   feathers, and assorted natural and human refuse, near denning sites, perhaps   for protection.  Houses are used year-round for life.  Small piles of sticks, fecal pellets, or debris   on rock ledges often are diagnostic.  
Tracks:  Front foot is 5/8" long by 3/4" wide; rear foot is   1 1/4" long by 3/4" wide, with a stride of 2 to 3 inches.                                           
Scat:   Often accumulated in heaps near the den site, in dense, black tar-like   material.  This material may extend over the edge of rocks as a sticky   overflow.  Nearby, may also be   white-stained urine spots. 
Remarks:   Aka the Allegheny woodrat or "pack rat" because of itï¿½s bulky   stick nests (and habit of collecting shiny objects); distinguished from house   rats by the hairy tails (not scaly). They also have larger ears. Known to   rapidly drum with their back feet when disturbed.  Good climbers woodrats frequent cabins in the woods. Wood rats defecate   outside the house, in noticeable piles. Despite shared habitat with   rattlesnakes and copperheads, woodrats are not part of the snakeï¿½s diet.
Recent   works (1990, 1992, & 1993) have split the Appalachian wood rat from the   eastern woodrat (N. florida), based   on DNA, and behavioral and ecological differences. For example, the eastern   woodrat is a generalist in habitat while the Appalachian woodrat is a   specialist among rock cliffs and talus slopes. Additionally, the eastern   woodrat often makes large stick mounds that shelter a nest, while the   Appalachian woodrat almost never will. Originally, these two species were   accepted as separate species early in this century, then lumped together as a   result of studies made in the 40's and 50's.  (Attempts in the 70's to produce hybrids in captivity failed as the N.   magister would usually attack and kill the N.   floridana.)
Precipitously   declining Appalachian woodrat populations appear to be the result of several   combined factors; decreased food supplies resulting from defoliation by gypsy   moths, infestations by parasites, and raccoon roundworm, transmitted by an   increase in raccoon numbers.
Virginia   nongame reports from 1992 through 1995 found that there are no longer any viable populations of woodrat in Fairfax,   Loudon, Frederick, and Clarke.
 
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  Subfamily   Murinae - Old World Rats and Mice
Three   species, the Norway and Black rat and the house mouse, have been introduced   into the New World and have been established over most of the country as   pests.  These introduced rodents   are characterized by long, naked tails.  The   Norway and Black rat carries diseases, including the bubonic plague.  The house mouse, found throughout homes everywhere, is also abundant in   agricultural fields and open waste places. 
A   summary of general characteristics only will be provided for these three   species.
NORWAY RAT (Rattus norvegicus)
(rat;   from Norway)
Head   and body 7 to 10 inches. This introduced "wharf rat" is identified   by itï¿½s long, hairless, scaly tail. First introduced around 1775, this is   the ubiquitous rat of warehouses, slums, etc. They maintain a very small range   often of less than 200 feet in diameter. Colonies of these rats are common   with 10 to 20 individuals, under the rule of male dominance hierarchy.   Probably the most omnivorous mammal of all. Breeding throughout the year   (averaging six to eight per year) with an average of nine per litter, the   young are sexually mature at three months. This species is the source of the   laboratory rats, in part, due to itï¿½s remarkably high fecundity rate. Most   of the lab rats are inbred pink-eyed albinos.
BLACK   RAT (Rattus   rattus)
(rat;   rat)
Head   and body 7 to 8 inches. Aka "roof rat", it is often not black, is   smaller than the Norway rat, but with a longer tail. Apparently introduced   with the Spaniards in Central America in the 1500s and with the Jamestown   colonists in 1607.  Unlike the   more aggressive subterranean Norway rat, the black rat builds arboreal nests   in forested environments. Both often cohabit the same buildings, with the   larger dominant Norway rats on the ground and the smaller black rat in the   rafters. No interbreeding occurs. Although not quite as prolific as the Norway   rat, black rats average six to eight litters with six per litter per year,   becoming sexually mature at three to four months. Black rats are not common in   the Appalachians, preferring instead, the Piedmont and Coastal Plain.
HOUSE   MOUSE (Mus   musculus) (mouse; small mouse)
Head   and body 3 1/5 to 3 2/5 inches. Another introduced species, the house mouse is   found throughout the Appalachian region, usually around buildings, but   occasionally in fields. Forming large colonies, these prolific breeders have   from five to ten litters of about six per litter per year, the young breeding   at four to six weeks. Along with the Norway rat, the albino house mouse is a   staple of the lab research crew. They have strong scent glands (musk glands)   located near the anus.
 
Voles   (which includes the bog lemmings),  Muskrats, and the true Lemmings.
SOUTHERN RED-BACKED VOLE (Clethrionomys   gapperi) (kind of dor-mouse, or   bolt-toothed mouse;   Mr. Gapper)
Appalachian   Region Distribution:   Clearly, a Canadian (boreal) species that extends south along the Appalachians   to about Springer Mountain, Georgia.
Continental Range: Throughout Canada, with southern extensions along   the Rockies and the Appalachians.   Seven   subspecies recognized in eastern US,   with two in the Appalachian region.
Abundance: They are common above   2,000ï¿½, often the most common small mammal in their favored habitat.
Population Density:  1-15 acre (up   to 26 per acre, decreasing throughout the winter).  Does not exhibit cyclic population explosions, but is   extremely variable.  Nowak reports a range from 5 -185/acre.
Size and Molt: Head and body is 3   2/3 to 4 2/3 inches; ï¿½ - 1 ï¿½ oz.   Two molts.
Mammae: Four pair.
Habitat: They prefer cool, moist,   rocky areas in coniferous forests, especially moss-covered logs and rocks.  Are also found in deciduous or mixed forests. 
Active Period: Active both day and   night (primarily nocturnal in summer and diurnal in winter), year-round. Like   other voles, they do not hibernate or exhibit periods of torpor.
Diet: Has a more varied diet than   other voles due to rooted cheek teeth.  Includes green vegetation, seeds, nuts,   bark, fungi (Endogone; making up a   substantial portion of the late summer and fall diet), with only a few insects   (less than the Peromyscus).  NAS mentions false lily of the valley, goldthread and bunchberry.  Does not routinely cache food in fall, but will store food in the nest   for use when the supply is short.  W/H says this vole lays   aside large caches of food in November.  Bark   and roots are the main winter food stay.  
Home Range: Nowak reports a summer   range of 3.5 acres and a winter range of 0.35 acres.  W/H reports   0.02 to 1.2 acres.  One study   reported a greater subnivean range (under the snow) in winter than summer   range.
Social Structure: Males stay with   the female and young for the first month, although it is not apparent that he   participates with child-rearing. In   captivity, females tend to establish dominance when in breeding condition, and   males were dominant when females were not in breeding condition.
Life Cycle: Females have two to   four litters per year (starting in mid-March through November) with an average   of four to six per litter (3.33 in SE Kentucky).  Larger litters are common ï¿½ up to   11 - at   higher elevations and further north. Gestation period of 18 days. Weaned and   on their own in 17 to 21 days with   sexual maturity in three to four months. Life span of one to two years.
Dens/Nest: Globular nests of 3 -   4", lined with grass, stems, dead leaves, and moss, under logs or roots,   brush piles, or may be in tree cavities, or burrows of other animals.  Although, generally thought of as an inhabitant of the forest floor,   several have been caught in nests 7 to 10 feet above the ground.  In the winter globular nests of grass may be placed directly on the ground   under the snow, with tunnels radiating from the nest under the snow.
Tracks:   Semi-fossorial, they prefer to hunt and travel along shrew and other small   mammal tunnels, rather than surface runways.  They will use runways of other rodents, however.  Tends to trot, rather than hopping, like the deer   mouse (NAS says they usually hop, but also run). Unlike the   meadow vole, the red-backed vole doesnï¿½t make extensive tunnels.  Rather, it utilizes tunnels made moles and shrews with other woodland   creatures.
Scat:   Concentration of scats is usually found.  Although, fecal pellets may be found scattered throughout a busy area.
Remarks:   Aka, boreal red-backed vole. Has a red and gray phase (gray is more common in the   north - reportedly the dominant gene and red the recessive gene). Good   climbers. Specimens from NC and southern VA are slightly larger and much   darker in color than those from northern VA and MD. (W/H says southern   Appalachian populations are decidedly larger than their northern relatives.)  May have a cyclic population peaking every few years, like   the meadow vole and some lemmings.  Known   to girdle fruit trees, and known to have meat that is tender and   well-flavored.
Together   with the deer mouse, the most abundant species found on the summit of Mount   Rogers, VA.
 
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ROCK   VOLE (Microtus   chrotorrhinus) (small ear; yellow nose)
Appalachian   Region Distribution:   A medium sized vole of NE Canada, the rock vole extends south along the   central ridges of the Appalachians continuously as far south as PA. At that   point, the next population is disjunct by about 250 miles to southeastern WV   and Bath County VA, eastern TN and western NC at high elevations.  Type locality is from
the Great Smoky Mountains National Park, approximately five air miles north of   Smokemont , Swain County, North Carolina on a tributary to Bradley fork.
Continental Range: NE   Canada, extending south along the Appalachians in disjunct populations to the   Smokies.  Two   subspecies are recognized in the eastern US.  M. chrotorrhinus carolinensis is designated as near threatened by   the IUCN.  It is endangered in  Virginia because of the logging of   old-growth spruce forests.   A second subspecies is found in   northern PA and to the north.  
Abundance: Rock voles, although   considered rare, can be locally abundant in good habitat (but are usually   outnumbered by other species in its habitat).  
Population Density: Unknown, but   has a four year population cycle.
Size and Molt: Head and body 4 to 4   4/5 inches; 1 - 2 oz. Males may be   slightly larger than females. Two molts.
Mammae: Four pair.
Habitat: Itï¿½s preferred habitat   is cool, wet, moss - covered (or herbaceous plant-covered, especially   bunchberry) talus or scree slopes (often above timberline at Mt. Washington,   NH) in northern hardwoods and mixed deciduous-coniferous forests.  It is found in habitats of mixed deciduous red spruce forest along with rock and talus and a ground cover of mosses and ferns.  It may also utilize recent clearcuts.
Active   Period: They are active both day and night (primarily early in the day),   year-round.
Diet: Green vegetation, roots,   fungi, insects and berries.   Supposed foods of the rock vole in New England and Minnesota include blueberry leaves, stems, and fruits;   foliage of Clinton's
lily, wild lily-of-the-valley, and bunchberrys; fruit of raspberry and blackberry; and mushrooms. Grasses and sedges may be of   lesser importance as food items.  Bunchberry   is known to be a favored food where available.
Home Range: Microtus generally seem   to be about 0.25 acres or less.  Males have larger   overlapping home ranges than females, and both have protected territories.  Young will disperse during the breeding season, but may remain within   the parental range late in the season and overwinter there.
Social   Structure: Territorial, living in isolated colonies, these voles share   their habitat with southern red-backed voles, deer mice, woodland jumping mice   and assorted shrews.
Life Cycle: Litters are born   throughout the growing season, averaging two or three litters a year with   nearly three per litter. Exhibits post-partum estrus. Gestation period of 19 -   21 days.  Weaned in three weeks.  Chapman and Feldhamer says microtus female may ovulate as early   as three weeks of age, with males requiring more than six to eight weeks   before sexual maturity.  This helps prevent sibling incest, with females pregnant   before male maturity.  Life span   of less than  two years.
Nest: They make their nests under   or above the ground, made of grass, about 6 to 8", with entrances on both   sides. 
Tracks: Utilizes runways beneath   and between rocks.
Scat: Concentration of scats is usually found.  Although, fecal pellets may be found scattered throughout a busy area.
Remarks:   Aka the yellownose vole.  It is   very similar to the meadow vole, with a reddish orange mark on both sides of   the nose and on the cheeks.
 
The   microtus voles have short tails (less than the body and head) and ears that   are nearly concealed by the pelage. 
The   existence of rock voles is often revealed by the accumulations of freshly cut   vegetation cached under flat rocks at the edges of streams.
Often   found in association with the southern red-backed vole (Clethrionomys gapperi).
 
Although there has been considerable effort to locate rock voles in Virginia, to date it has been found only in the Valley of Little   Back Creek, Bath County.  Rock voles are considered a relict species.  Habitat on Whitetop and Mount Rogers   appears suitable. It is likely they occurred in Giles, Tazwell, and Russell counties before the spruce was cut around 1900.
MEADOW VOLE (Microtus pennsylvanicus) (small ear; from Pennsylvania)
Appalachian   Region Distribution:   Throughout.
Continental Range: Canada and northern half of US. - as far south as   the Smokies. One of the most widely distributed small mammals in the world,   certainly the largest of any North American vole.  Five subspecies are   recognized in eastern US, with one in the Appalachian region; two restricted to island populations.
Abundance: The most common vole   in eastern US.  Wilson says the   most prolific mammal on earth.
Population   Density: Cyclic populations creates a wide range of figures.  W/H reports a range from 1.6/acre to 73/acres in Indiana.  Nowak reports densities of 92 - 292/acre in old fields and 292-925/acre in marshes, with peak populations reaching 2,500/acre in three or four year cycles.  Annual population fluctuations occur as well as cycles,   resulting in boom or bust years.  Cyclic   populations seem to be more pronounced in the northern range, but seem to   occur throughout the total range at the same time.   Cyclic fluctuations ranged from 166   versus 49 per acre and 36 versus 4 per acre in two Canadian studies.  Such cycles have been observed in VA.  A Giles County VA study reported peak densities of 40 per acre.  Annual populations have been reported to be inversely related to the   population of short-tailed shrews.  See remarks below.
Size and Molt: Head and body 3 ï¿½ to 5 inches; 1 - 2 ï¿½ oz. Males are slightly larger than females. Two molts.
Mammae: Four pair.
Habitat: The meadow vole is a   relatively large mouse, preferring grass dominated open wet meadows, low,   moist fields and openings.  Meadow   voles love bluegrass fields.  They   spend most of their time above ground. Shares its habitat with hispid cotton   rats, meadow jumping mouse, southern bog lemming, and the marsh rice rat. 
Active Period: Active both day and   night (mainly crepuscular), year-round.  Will   tend to be nocturnal in summer.  Can   be active over a 24 hour period, related to season, weather, and habitat   quality.  Less active during a full moon (I just write it down).
Diet: They are highly herbaceous, including green vegetation and tubers.  Herbaceous vegetation in summer and bark and roots in winter.  Voles will also eat insects, fungi, and carrion.  They are known to eat their own weight within a 24 hour period.  Meadow voles are also known to practice coprophagy.  In fact, one 1989 study found that meadow voles reingested about 12% of   their feces when on a low-quality diet. 
Home Range: 1/10 - 1 acre.   Nowak reports a Kentucky study finding a home range of 358 ydï¿½ for males and   167 ydï¿½ for females.  Stokes   says males are 200 square yards; females 75 square yards.  Wilson says females   average 84 square yards. Wilson   and W/H says male home ranges are about three times larger than female home   ranges and may overlap the ranges of several females and of other males.  Only small areas near the nests will be defended (their "territory"). 
Social Structure: Solitary and   territorial during the breeding season and communal in winter.  Both males and females are promiscuous.  Both sexes are seasonally aggressive, with males fighting viciously among themselves, with the females tending to dominate the males.  Breeding females vigorously protect their territory from other females,   as can be evidenced by the many chewed ears of captured individuals.  Juveniles from late broods may overwinter with the mother, along with   one or two adult males, to form an extended family group (energy conservation   through "huddling" can then be gained).
Life Cycle: The most prolific   mammal in North America.  Breeding   occurs throughout the year (primarily April to November) with an average of   eight or nine litters (average of 3.5 in Canada) with a litter size of five to eight (1-11)(postpartum estrus   results in new pregnancy within hours of birthing). Largest litters occur in   summer.  One female in captivity   had 17 litters in one year. Gestation period of 21 days. Weaned in 12 to 14   days, with sexual maturity reached at 25 days for females and 45 days for males. Life span is   usually less than a year. One study indicated an average longevity of less than one month.  Populations   are often cyclic, reaching highs every three to four years, but this cycle   does not always occur.                                       
Nest: The 6-8"spherical grass nest may be located in the burrows in summer or in a depression on the surface under matted vegetation, with entrances on both sides. In the winter, will place the nests on the ground surface if winter snow is reliable.    
Tracks: Hindprint 5/8" long with 5 toes; foreprint 1/2" long, with 4 toes.  Hindprints ahead of foreprints, with distance between individual walking prints (stride) 1/2 - 7/8".       Straddle is 1 1/2".  Like all voles, meadow   voles make clear runways in the grass (about 1 ï¿½" wide).
Scat: Small, elongated, dark pellets.  Concentration of scats   is usually found.  Although, fecal   pellets may be found scattered throughout a busy area.
Remarks:   Aka field or meadow mouse.  Often   the main small herbivore of open fields.  Known to girdle fruit trees in winter.  Meadow voles invade fallow fields and build large populations until the   habitat matures, shading out the herbaceous growth favored by the meadow vole.  Their exploding populations have been known to be catastrophic to   agricultural crops, such as in Humbolt County, Nevada from 1906 - 1908, when   population densities of 10,000 voles per acre totally denuded 25,000 acres of   alfalfa.  Fields were honeycombed   by holes up to 24,000 per acre.  (This   is attributed to the montane vole; Microtus   montanus.)  Members of this   genus (Microtines) have adapted to a high-fiber, low nutrient diet, evolving   hard enamel grinding teeth and having some of the longest length caecum and   large intestines for digestion of herbivorous rodents known.  Meadow voles practice coprophagy (ingesting fecal pellets), primarily   in the period of inactivity following the cessation of feeding.  Good swimmers, but not arboreal. Being so prolific, they are a mainstay   of the prey for the predatory species. Cyclic populations, with maximums   occurring about four years apart, are associated with voles and lemmings,   although much research needs to be done to establish the nature of the cycles,   which seem to reflect available habitat, and don't have reliable spans of   times or densities. 
Populations   from Chincoteague, VA, are notably darker than specimens from more northern   population, being nearly black on the rump.
Individuals   from the southern part of the Appalachians are larger and darker than the   northern population.  Can be found   sharing the same habitat with the cotton rat, meadow jumping mouse, southern   bog lemming, and the marsh rice rat. 
In   1804, Lewis and Clark found and recorded the Indian custom of raiding the   underground stores of native mice.   One meadow vole cache included beans produced on the underground shoots   of a trifoliate bean vine and artichokes as tubers of a wild sunflower.
 
WOODLAND VOLE (Microtus   pinetorum) (small ear; of the pine grove)
Appalachian   Region Distribution:   Throughout.
Continental Range: East of the Great Plains and south of Canada.  Seven subspecies are recognized in eastern US,   with two in the Appalachian region.
Abundance: Variable.
Population Density: 1-50/ acre.   (W/H says up to 6 per acre.)  Not   known to have cyclic population booms, rather, they have a K-selected   structure; low reproductive rate and a stable population size.  This is possible because of their fossorial nature, making   them less susceptible to predation.  None-the-less, fluctuations are   known to occur with maximum densities reaching 1,250 per acre.
Size and Molt: Head and body is 2   4/5 to 4 1/5 inches; ï¿½ - 1 1/2 oz.   Two molts.
Mammae: Two pair. (Note this is   half as many as the meadow vole - see Life Cycle below.)
Habitat: Prefers a dry, deciduous   forest.  A very "fossorial" mammal (subterranean). Wide range, from coastal areas in the south to spruce   and birch forests of the northern mountains.  Despite their species name (given from its type location habitat in the   pine forests of Georgia), they are more often found in deciduous forests with   deep humus, not pine woods (woodland vole is a better characterization). Also   found commonly in dense grass, forbs, and brush, orchard, fields and in   gardens.
Active   Period: Forages both day and night, year-round, mainly underground.  They have a regular pattern of one hour of activity, followed by an   hour of rest.  Tends to be more   fossorial in summer.
Diet: Grasses, insects, and forbs   in summer, seeds and fungi (the subterranean Endogone)   in fall, roots and bark in winter.  In addition to grasses and forbs, poke berries, wild onions, and wild morning   glories are eaten.  Known to cache food on occasion. More   varied diet than the meadow vole.
Home   Range: ï¿½ acre.  W/H says 430   ï¿½ 485 square feet per ï¿½unitï¿½, consisting of two adult males, one adult   female, and one or two young. 
Social Structure: Woodland voles   can be social and monogamous, with small groups of adults and their young   (usually four or five, although 11 has been recorded) living in a single nest.   Not territorial, like the meadow vole.
Life Cycle: Postpartum estrus   enables many litters (4-6) (NAS says 1-4) throughout the breeding season (from February to   November) with an average of two to three (1-5) per litter. Gestation period of   24   days. Young are weaned in 20 days, with males reaching breeding age at 6 to 8   weeks and females at 10 to 12 weeks.  Chapman   and Feldhamer says microtus female may ovulate as early   as three weeks of age, with males requiring more than six to eight weeks   before sexual maturity.  This helps prevent sibling incest, with females pregnant   before male maturity.  Female   approaches, nay, attacks the male to copulate.  Woodland voles are not cyclic, as meadow voles are.  Rather, they are K-selected;   adopting a low reproductive rate and maintaining a stable population (versus   the R-selected high reproduction rate and high mortality rate method).  This is reflected in the woodland vole having only four teats, half the   number of the meadow vole.  Life   span is 12 to 18 months (longer than the meadow vole, as would be expected by   the K-selected strategist).
Nest: Unlike the other microtus,   the woodland vole is almost wholly subterranean.  The globular nest of dead grasses, roots and leaves (6 -7" diameter ) is found beneath stumps and logs, and at the end of burrows, in a   nesting chamber with three or four openings.
Tracks: Woodland voles make their   own burrows (1" in diameter) 3 to 4 inches under the surface in the humus   layer (although, occasionally tunnels may extend to a depth of 12 inches or   more).  In orchards, burrows often   follow apple tree roots underground.  They   also will take over abandoned mole foraging tunnels, but donï¿½t seal off   entrances, like moles do.
Scat: Concentration of scats   is usually found.  Although, fecal   pellets may be found scattered throughout a busy area.
 Remarks:   Aka pine vole. Notice the woodland vole is not a boreal species. These voles   are known for damaging orchard trees by girdling the trunk, particularly in   the Shenandoah Valley. They also have a preference for potatoes. The woodland   vole doesnï¿½t have the breeding potential of the meadow vole, but, being more   fossorial (underground), doesnï¿½t lose as many to terrestrial hunters. Also not known to   have cyclic population booms.
A   fossorial vole, its pelage is especially adapted with short fur that lies flat   against the body, whether rubbed forward or backward, like moles.
Woodland   voles in southern range have smaller feet and brighter pelage than more   northern populations (MD and north).
Often   found in the same habitat with hairy-tailed moles, frequently sharing the same   burrow systems.  Other neighbors   include jumping mice, red-backed voles, white-footed and deer mice, meadow   voles, smoky and short-tailed shrews.
COMMON MUSKRAT (Ondatra zibethicus) (Huron Indian word for muskrat; musky odor)
Appalachian   Region Distribution:   Throughout.                        
Continental Range: Throughout   North America, except SE piedmont and coastal plain and deep SW US.  Three recognized subspecies   exists in eastern US, however, only two exist in the Appalachian   region.  The species type locality is Lake Drummond, VA, in the Dismal Swamp.
Abundance: More common along lower   elevation streams, where adequate habitat is more likely to be found.
Population Density: Extremely   variable, based on numerous factors, such as phase of the population cycle,   habitat type and condition, social pressures, competition, harvest, predation   and geographical area.  Densities   range from 3 to 25/ acre.  However,   densities in Appalachian regions must be assumed to be much less, due to   limited adequate habitat.  Nowak   reports 17/acre in open ponds, up to 217/acre in cattail marshes.  W/H   reports 2.8 houses (families) per acre.  Wilson says 16 per acre is normal in good habitat, with up to 60 per   acre during population peaks.  Densities   in coastal marshes have higher densities; up to 122/acre in cattail habitat.  Muskrat   cycles of six, ten to 14 years have been recorded, with ten year cycles most   commonly reported.  However, such   cycles are not exhibited in fresh water marshes.
Size and Molt: Head and body 9 to   14 inches, 2 - 4 pounds (maximum of 5 pounds). Males are   slightly larger than females.  It can be assumed muskrats found in   Appalachian streams and rivers will be on the small size, based on food   quality and quantity compared with coastal marsh/ broad piedmont-coastal plain   rivers.  One molt. 
Mammae: Three to four (rarely five)   pair of teats are present. Nowak says females usually have two pairs of   inguinal and two pairs of pectoral mammae.
Habitat: Marshes, along   watercourses. Prefers brackish waters.
Active Period: Nocturnal and   crepuscular, but can be active throughout the day.  Active year-round.  Will   be more active on cold frosty nights and less active on warm muggy, or windy, nights.  One study found that muskrats do less work during periods with a full moon.
Diet: Mainly vegetarians   (principally cattails and bulrush), but is supplemented in winter by   crustaceans, mollusks, and fish (apparently affecting the recovery of   Federally listed endangered mussels species in SW VA.)  Eats a third of its weight each day.  Like beaver, they can close their upper lips behind the incisors in   order to cut materials underwater without taking in water.  Unlike   beaver, muskrats generally do not cache food for winter
Home Range: 33 - 600 feet in   diameter, averaging 200.  Along   rivers and streams, home range has been recorded at 600 feet of linear bank.  Have good homing instincts (31% return when released nearly two miles   away).  Males will defend about 5-10 acres from other males; females will   defend 2.5-5 acres from other females.  Male territories may overlap   those of more than one female.  
Social Structure: Rather territorial (not as much as beaver) and not social, except in   winter, when several may occupy a nest (as many as 12 have been found in a   winter den - often young offspring).  Males and females   have been variously reported as polygamous or loosely monogamous, being   especially quarrelsome during the breeding season.  The male is forced out just prior to birthing, but may rejoin the female and   young after nursing to maintain the house and to defend a feeding territory.  
Life Cycle: Two to three litters   with an average of three to six (1-11) per litter per year is common, with peak   breeding period from March -  June, the first brood being born in   April.  Polyestrous females, with possible   postpartum estrus.  Gestation period of 25 - 30 days. Altricial young.   The male rarely cares for the kits.  They are weaned in one month, dispersed soon after weaning (prior to next litter).  Breeding age of one year.  Mortality is high with one study finding as many as 65% of young   muskrats dying by January.  Winter harvests are usually composed of approximately two   thirds young of the year and one third adults.  Life span does not exceed five years, but ten years in captivity is   known.  (Like numerous rodents, litters of more northern populations are   less, but have more young per litter.  Sexual maturity is also affected   by the length of the season.  In the case of the muskrat, southern   populations have 5-6 litters per year with 2.4 young per litter and can have   spring young mating by fall, while Canadian populations will have two litters   with 7.1 young per litter and not be sexually mature until the next spring.   This Appalachian study area falls somewhat in the middle of these two   extremes.)
Dens/Nest: Muskrats normally make large   grass and reed lodges (two to four feet high and six to eight feet across) in   marshy, shallow water (about two feet deep) habitats.   In   deep streams, rivers and lakes, muskrats can make their lodges in the banks   (thus, the term "bank rats"), forgoing the exposed location of the   grass lodge.  Bank burrows are often used   throughout the year, or, occasionally, only in summer, with constructed houses   in the fall and  "pushups" in winter.   Bank dens   generally are 6-8", with depths varying from surficial to over 5', with   an air shaft constructed in dense soil.  Such dens are connected to water   by numerous tunnels 4-6" in diameter and 9-45' long.  Construction   of lodges usually occurs in the early spring after the   main dispersal, or in late fall, when a lesser dispersal occurs.   Like the beaver's wood dam, the material is piled up solid, and then the   muskrat dives underwater and cuts/digs its way up into the center of the house   where it creates its living chamber above the water level.  The size and height of the houses vary, depending on the quality of   habitat, range of water level, and number of occupants, but average up to 7-8'   in diameter and 1-4' in height.  One-foot thick mud walls insulate both in summer and winter.  Like the bank den, there is usually more than one entrance to the lodge, normally 6ï¿½ to   12ï¿½ under the surface.  Tunnels (up to 15ï¿½) extend from the dry interior nest area   of the house to the surrounding marsh.  Lodges can be used   for twenty or more years by generations of muskrats. Lodges normally will hold   two adults and two to four young.  Often   two internal nest chambers are constructed.  Sometimes,   a second house is connected to the first, forming a "double house",   and 10 to 15 muskrats may live together.  Usually, houses are dome-shaped structures, but lodges in Maryland   often have slanting or flat tops.  Lodge   temperatures are about 36 degrees F warmer than outside temperatures.  Makes several smaller, covered feeding huts (or, feeding   rafts) near the nest (normally 2' by 2'), where piles of food remains will be found. Like the   nest, both have underwater entrances.  These are commonly used in winter, while summer finds them using feeding   shelves on the side of their houses.  Within   a few yards of the main lodge will be several ï¿½pushupsï¿½, where muskrats   can extend its feeding range when the marsh is icebound.  Muskrats are even known to make nests in hollow logs or stumps, when   normal shelter is not available.
Tracks: Tracks are small hands;   four toes in front and five toes in rear.  The front foot can have a grooming spur on the side so it looks like   five toes in front. Hind foot is 2 to 3" long, foreprint is half as long.  Hindprint can be ahead of or behind foreprint, sometimes overlapping.  Stride of 3".  Canals are frequently constructed from the house to deeper water, or   when summer droughts cause low flow, being   from seven to ten inches wide.
Scat: Brown, oval, about 1/2 " long and about 3/8" in diameter.  Rue says they look like date pits.  Often uses the same spot on rocks or logs along the edge of the body of   water.  Generally, 3 to 4 (up to 12) black, oval droppings are deposited at one   time.  Such areas often smell of   the strong-smelling yellow musk.
Remarks:   This is the only species in the genus Ondatra.  
The semi-aquatic muskrat is   classified as a large water vole. Muskrats get their name from   the musky odor emanating from the preputial glands found along the penis   (especially notable during the breeding season).  Apparently, it is also an adulterated version of the   Algonquian word for the muskrat; musquash.   They exist, much reduced, in females as well. 
Muskrats   benefit other wildlife by creating openings in vegetated wetlands.
 
The muskrats main enemy is the mink.  Generally, where you find muskrat, you find mink.  However, 70% of the time, the mink is preying on aged or dying muskrats, not healthy muskrats.  Raccoons are the second enemy, commonly tearing apart muskrat dens, that are not as solid as beaver dens.
Muskrats   are more ubiquitous than beaver due to their more omnivorous diet and less   demanding habitat.  Unlike the   closely related meadow vole, the muskrat does not undergo population   explosions, but does have a ten-year cycle of abundance. Muskrats can swim   underwater up to 20 minutes without breathing by building up lactic acid in   the muscles and bloodstream, a common ability of diving animals (they also   have a high tolerance for carbon dioxide). Breaks through ice in winter,   pushing up lots of vegetation (pushups), serving as a temporary opening and   feeding station. Like beaver and otter, they can close their upper lips behind the   incisors in order to cut materials underwater without taking in water.
Muskrats   are the most popular fur-bearing mammal in North America.  In the season of   1976-1977, 7,148,370 muskrats were trapped in North America. (200,000 per   year in PA.  The same for Virginia   for 1984-85.)  Mammals of Virginia   says between 10 and 12 million pelts taken every year in North America until   recently.  A million pelts taken   during the 1987 season in NY averaged $5.00 per pelt.  They are not in short supply.   However, the average price per pelt in Virginia has dropped from $6.90   in 1979 to $0.95 in 1990, resulting in a drop in trapping in Virginia to   15,561 in 1990-91.  Known in the   mid-Atlantic markets as marsh rabbits.
The   introduction of the nutria from South America (for sport and removal of   introduced herbaceous plants) has reduced available habitat for the muskrat,   due to the larger, more competitive nutria.  Nutria not only out-compete the muskrat, but literally destroy the   wetlands by pulling out the tubers and roots of itï¿½s food sources.  Also, spraying marsh areas with insecticides dissolved in fuel oil to   control mosquitoes can cause severe declines in muskrat populations, due to   the oilï¿½s wetting effect on the fur, causing the muskrat to sink below the   surface and remain thoroughly wet.
Albinism,   mutation, and pigment dilution cause color variations from white to black.  A uniform black is found in Virginia and North Carolina marshes; a ï¿½fawnï¿½   color is found in the Chestertown, MD area; and a ï¿½Maryland whiteï¿½ is also   identified where young individuals are maltese gray but white underneath.  Generally, muskrats from the piedmont and coastal plain of MD, VA, and   NC are slightly darker in color and larger in size than those from the   mountains. 
In   the category of more than you ever wanted to know, W/H says ï¿½Because   the clitoris lies anterior to the vaginal opening and resembles the penis, the   male and female genitalia are superficially similar.  The distance from the anus to the genitalia is greater in males, and   the perineum is furred in males but naked near the urethra in females.ï¿½
 
SOUTHERN BOG LEMMING (Synaptomys   cooperi) (unite, mouse; Mr. Cooper)
Appalachian   Region Distribution:   This is a chunky, medium-sized boreal vole that is found throughout the   Appalachians and adjacent foothills as far south as Springer Mountain.
Continental Range: NE US. and   SE Canada.  There is a disjunct subspecies in the Dismal Swamp of Virginia/North   Carolina which is at least endangered and possibly extinct (S. cooperi helaletes).  Five subspecies are   recognized in eastern US,   with two in the Appalachian   region.
Abundance: Localized in small,   isolated areas and   generally uncommon.  More common   in the mid-west.
Population Density: 2-5 per acre.   Mammals of Virginia reports up to 20 per acre, although concurs that 2 ï¿½ 5   is more representative.  Nowak reports a range from 15-87/acre.  W/H   reports 1.6 to 4/acre is usual in good habitat.
Size and Molt: Head and body 3 2/5   to 4 2/5 inches; ï¿½ - 1 ï¿½ oz. One   molt.
Mammae: Three pair. (Mammals of   Virginia says 6 to 8.)
Habitat: Exceedingly variable.  In this southern part of their range, they are found in wet bogs and   cold spring areas.  In the north, grassy meadows and woodlands with heavy   vegetation (including clubmosses), and dry hillsides can be populated.  Succulent monocots, such as sedges and grasses seem to be the key.   Small patches of suitable habitat may contained isolated populations.
Active Period: Mainly   nocturnal, but can range from diurnal (in winter) to crepuscular, year-round.   More nocturnal than voles.
Diet: Green vegetation (especially   grasses and clover), berries, a few invertebrates (slugs and snails),  and the subterranean fungus Endogone.  One SW VA   study revealed sedges in summer and mosses in winter.
Home Range: 1/3 acre.   (Nowak reports 0.2-0.5 acre, W/H   says 0.02 ï¿½ 0.13 acre, Mammals of Virginia reports 0.1 to 1 acre.  Wilson says 0.016 to 0.25 acre.  Whateverï¿½)  
Social Structure: Quite sociable,   occurring in colonies ranging from a few to several dozen.  The area around the nest is defended.  
Life Cycle: Two to four litters   (March through October) averaging three (1-8) per litter per year.  Females are   seasonally polyestrous and may have a postpartum estrus.  Females have   litters every 67 days during the spring and summer.   Gestation period   of 23 days.  Weaned in three   weeks, becoming reproductively active in about eight weeks (Nowak says 5 weeks   for males). Life span of about   eight months with two years known in captivity.
Den/Nest: Nests (3 ï¿½ - 6" diameter) concealed in hollows under sphagnum mounds, logs, or stumps or in   grass tussocks, normally below the   surface, occasionally on or just above the surface with 2-4 entrances.  Constructed of dead   grasses and leaves, occasionally lined with fur.  Always well-concealed.   Often   shares the same burrows with other small mammals.                 
Tracks:   An underground tunnel system is common (6" depth), also constructs extensive surface   runways, like voles.  In such highways, the grass is always cut and trimmed to keep   the passages smooth. Known to cut grass stems one to two inches and deposit in   piles along runways.
Scat: The use of the runways   by meadow voles or southern bog lemmings can be determined by the color of   scat; dark brown or black for voles versus bright green or yellowish of   lemmings. 
Remarks:   Bog lemmings are classified as voles.  They can be recognized by their very short tails. The meadow vole and   southern bog lemming seem to share similar habitat, with the meadow vole being   more competitive for limited habitat. In a Kentucky woodland clearing, the   meadow vole is invading and replacing the southern bog lemming. Often found   with red-backed voles, deer mice, prairie voles, moles, and various shrews;   sharing the same burrows with them.
Their   presence can be detected by neatly clipped piles of grass cuttings and   tell-tale green droppings.
 
 
Family   Zapodidae - Jumping Mice
The   jumping mice were originally described in the Dipodidae family, later placed   in the their own family; Zapodidae.  But   recent work (1990 and 1992), places them in the subfamily Zapodinae, in   the family, Dipodidae, as indicated by Nowak's   Walker's Mammals of the World .  However,   Jones 1997 Checklist of North American Mammals still lists these two jumping   mice in the Zapodidae family.  So be   it.  The   jumping mice are apparently more closely related to porcupine than to other mice.
The   two species can occupy the same area where herbaceous ground cover is abundant   along a stream leading into woods.  While   the meadow jumping mouse may enter the woods in the absence of the woodland   jumping mouse, the opposite is not likely to occur. 
The   larger woodland jumping mouse can jump up to 12 feet; four times the length of   the meadow jumping mouse.
 
Two   species, representing two genera are found in this Appalachian region.
MEADOW JUMPING MOUSE (Zapus   hudsonius) (very large hindfoot; from the Hudson Bay)
Appalachian   Region Distribution:   Throughout.
Continental Range: From Alaska through Canada and   Northeast/northcentral US.  Five   eastern US subspecies recognized, with only one subspecies in the Appalachian region.  
Abundance: Uncommon. Tend to be   localized in distribution and has annual fluctuations in populations.  Reportedly abundant on Assateague Island and certain areas proximate to   the VA Blue Ridge.
Population Density: 2-8/ acre, up   to 19/acre..
Size and Molt: Head and body 3 to 3   1/3 inches; ï¿½ - 4/5 oz. Females are   slightly larger than males. One molt.
Mammae: Four pair.
Habitat: The meadow jumping mouse   prefers wet meadows, open grassy areas or dry fields with streams running   through them. Often particularly abundant in patches of jewelweed (impatiens).  Where both the meadow and woodland jumping mice occur, the common name   indicates their relative preferred habitats, although, in the absence of the   woodland jumping mice, the meadow jumping mice will populate the woodland   habitat. 
Active Period: Primarily nocturnal,   although occasionally out during the day. These creatures are deep   hibernators, sleeping about half of the year, accumulating body fat in fall.   They arouse from their ground nests (which may be shared by several or singly)   two to three feet underground every month or so to defecate and urinate. Males   emerge in April, a week or so before the females, and reenter torpor in   November.
Diet: Seeds predominate year-round.  Diet includes caterpillars and beetles in spring, grass and herb seeds   in summer, along with berries, roots, nuts and invertebrates. Fungi   (especially Endogone-up to 15% of itï¿½s fall diet-found by smell) and fruit are   favored in fall. The jumping mouse eats nearly half itï¿½s weight per day. A   hibernator, it does not cache food.
Home Range: ï¿½ - 2 1/2 acres; a wide   range, due to their wandering nature.  Males have a slightly larger home   range than females.  
Social Structure: Solitary, except   to hibernate, when several may share their warmth.  Generally, they are   not antagonistic. 
Life Cycle: Breeding after spring   emergence, they usually produce two or three litters (late May, July, and late   August)  with an average of five   (2-9) per litter per year. Altricial young, weaned between four and five weeks.   Gestation period of 20 days.  No   postpartum pregnancy. The first litter may mate by fall. Late litters often   cannot accumulate enough fat to survive hibernation.  Life span of two to four years, five in captivity.
Nest: 4" summer nest on surface, or   beneath brush, logs or stumps.  Winter nest (hibernaculum)  (4-6"  diameter), made of grass and leaves, is usually located in a burrow 2 -3 feet   underground.
Tracks: These mice do not forage in   runways or tunnels, rather they maneuver through the foliage.  Wilson says that, although they do not make their own runways, they use   those made by other species, such as voles.
Remarks:   The meadow and woodland jumping mice are the only true mammalian hibernators   besides the woodchuck and bats, with a body temperature only a few degrees   above freezing and its heart rate reduced to a few beats each minute.  Hibernation is triggered by means other than temperature.  It is believed that stored brown fat is one key.  Normally meadow jumping mice will accumulate a substantial layer of fat   (about 0.2 oz - nearly double its normal weight) to sustain it through its lengthy hibernation.  About two thirds of the population does not survive the winter   (normally young that havenï¿½t accumulated adequate brown fat).  Hibernation lasts between late September/October through late   April/May, longer or   shorter, depending on latitude.
 
Males emerge first, with females emerging two weeks later, with mating   immediately following.
The   meadow jumping mouse has enlarged rear feet and small, weak front legs and an   extremely long tail (4 -5"). It will take several hops of about a foot   each when alarmed, although they are known to hop as far as three feet and as   high as seven or eight feet. It is an excellent swimmer. 
WOODLAND JUMPING MOUSE (Napaeozapus   insignis) (woodland nymph with very large hind feet; insignia)
Appalachian   Region Distribution:   Throughout.
Continental Range: NE Canada and extending south along the   Appalachian mountains.  Three   subspecies are recognized in the eastern US,   with two in the Appalachian region.
Abundance: Locally abundant in   higher elevations within PA, MD, and VA; becoming restricted to suitable   habitats above 2,800ï¿½ in NC.
Population Density: About   3/acre, with a range from 1-24/   acre.
Size and Molt: Head and body 3 3/5   to 4 inches; ï¿½ - 1 oz. Females   slightly larger than males. One molt.
Mammae: Four pair.
Habitat: The woodland jumping mouse   prefers cool, damp spruce or hemlock-hardwood mountain forests, especially moss-covered rocks along   mountain streams.  Areas of dense   herbaceous growth in moist habitats, or rhododendron thickets along streams,   are preferred.  Has a much more   restricted habitat than the meadow jumping mouse.  Can be found with the meadow jumping mice in prime habitat of   jewelweed, where a stream runs from the woods into a field. Also, can be   commonly found with southern red-backed voles and northern water shrew.
Active Period: Nocturnal. Profound   hibernators, spending from September to May in deep torpor in   underground moss/grass/leaf nests, awaking about every two weeks.  May put on one third its weight within two weeks in fall. Males emerge   a week or two before females.  
Diet: They feed heavily on   subterranean fungi (Endogone; up to   a third of the diet of 103 sampled in New York and 40% of a Smokies study of   16 jumping mice.) and seeds (constituting 75% of the diet of another New York   study ï¿½ especially the bright turquoise-colored impatiens seeds). Also   prefers insects.
Home Range: 1 - 8 acres, with males   having a slightly larger range.  Ranges of   both sexes overlap and are not antagonistic.  
Social Structure: Solitary
Life Cycle: Not having postpartum   estrus, only two litters per season occur (June and August), with an average of five   (2-7) per litter   is common. Gestation period of 30 days (compared to only 20 of the meadow   jumping mice), weaned in 30 - 35 days (Nowak says gestation period of 23   days).  If   the second litter is late in the season, the young often will not be able to   store enough fat to survive the winter hibernation (will accumulate 7 - 8   grams of fat). In fact, one study shows a 75% mortality in the second litter.   Another study showed 75% mortality of all hibernating woodland jumping mice.   May breed in first season or in the following year. By fall, 70% of the   population will be young of the year.  For those who survive, life span of two to four   years.
Dens/Nest:   Dens in underground burrows that it either digs itself or takes over.  The entrance is covered during the day.  Summer 5 - 6" nest of   dry grasses and leaves located under rotting logs or boulders, or in shallow   underground burrows. Overwintering hibernaculum is underground, under logs or   boulders, but not as deep as the meadow jumping mouse.
Tracks: Do not construct runways,   but will dig itï¿½s own burrows. Also will use existing burrows of other small   rodents.
Remarks:   Differs from the meadow jumping mouse by having a white tail tip.  Being much larger than meadow jumping mouse, can jump 9 to 12   feet. The hopping motion is called "saltatorial locomotion",   practiced by kangaroos, wallabies, gerbils and kangaroo rats.  The singularly most profound   hibernator of eastern mammals, the woodland jumping mice will spend up to six   months in hibernation. From New York, south through the Alleghenies, the   woodland jumping mice grades smaller and considerably darker. The scent glands   impart a sort of pleasant nutty fragrance, unlike the pungent musk of the   house mouse. 
The   jumping mice are apparently more closely related to porcupine rather than to other mice.  
The jumping mice were   originally described in the Dipodidae family, later placed in the their own   family; Zapodidae.  But recent   work (1990 and 1992), places them in the subfamily Zapodinae,  in the family Dipodidae.
So says Nowak.  But I'm going with the Checklist, which is different, of course.  So they will go in their own Zapodidae family.  Why can't these guys get along?
 
Family   Erethizontidae - Porcupine
The   porcupine is the only species of the 12 South American species (4 genera) that   has made the journey north into North America.  Only the beaver is larger than the porcupine among rodents. 
COMMON PORCUPINE (Erethizon   dorsatum) (irritate, animal; back)
 
ARTICLES
Appalachian   Region Distribution: Common in northern Pennsylvania, but rare in this   Appalachian region south of central PA.  The WV DNR reports that porcupines are found in the western Maryland counties   of Allegheny and Garrett, but that no populations of porcupines now exists in   West Virginia, despite isolated sightings in northeastern WV, possibly the   result of individual porcupines that were released into the state.   However, the habitat is suitable for porcupine and, with the proximity   of porcupines in Maryland, such future habitation is likely.  Early Europeans noted porcupine in VA, albeit notably scarce, even at   that time.  Audubon and Bachman   were unsuccessful in finding porcupine in VA in 1846.  It is now officially listed as extirpated in VA.  Porcupine records have been found from Indian sites dating from 6500 to   1000 BC in Tennessee and Alabama.
Continental Range: Throughout   Canada and from Rockies west.)  Only   the one subspecies (E. dorsatum dorsatum) exists in eastern US.
Abundance: Common in northern Pennsylvania, but rare in this   Appalachian region south of central PA.
Population Density: Varies   seasonally and in response to food supplies (and publication source).  Studies range from .03 to .4 per square mile in more northern habitat   to 2-25 / square mile in north-central Pennsylvania.  Nowak and Wilson note a population cycle that peaks every 12 to 20 years, with   studies supporting densities from 2 to 31 per square mile and 13-25/square   mile.  W/H reports a density of from 3 to 14 per square mile in the   east.  
Size and Molt: Head and body 17 to   31 inches; 10   - 15 pounds (males have   been recorded at 37 ï¿½ pounds). Males slightly heavier than females. Second   only to the beaver in size for North American rodents. One molt.
Mammae: Two pair.
Habitat: These arboreal mammals   prefer forests with both hardwood and softwood trees.  In the east, they prefer the mixed mesophytic forests and hemlock forests   areas. Another favored tree species is the sweet birch.
Active Period: Primarily nocturnal,   throughout the year, but is known to forage by day.  Juveniles   and females will stay in their den for extended periods in severe cold spells.  Large males may remain in a tree fork for days; its dense coat and   ability to drop its body temperature several degrees, providing adequate   protection.
Diet: Herbivorous, as all rodents;   but a strict vegetarian, one of only   a few among the rodents.  Seasonally,   there is a procession of foods, often determined by   seasonally varied tannin levels.  In   spring, porcupines feed on buds of sugar maple, basswood, and aspen.  Then, beech leaves, and later, ash leaves (along with various   herbaceous plants).   Summer diet includes   stems (especially aspen), roots, leaves, apples, berries, seeds, nuts,   flowers and grass.  Preference for aquatic plants, with the porcupine eating   from the shallow waters is well noted.  Late summer brought acorns   and beechnuts (the ground under oaks are littered   with the clipped twigs that porcupine drop before coming down to the ground to   eat the acorns off the twigs).  Corn is   also preferred.   Fall   diet includes mast as well as corn crops.  Winter diet is primarily wood cambium (prefers conifers, specifically   hemlock in the Appalachians). Variability in tannins among tree species causes   porcupines to favor spruce, white pine, elm, basswood, beech, and sugar maple,   while red maple and white ash are almost never eaten. Porcupine usually limits   its feeding to two or three species of tree per winter.  Known   to eat salt along roads (and anything that has been touched by sweating   humans).  Plywood is a good source   of salt.  Natural salt sources   include yellow waterlilies, liverworts and fresh bone and antlers.  This need for salt is exhibited among all medium-sized mammals, who   ingest huge amounts of potassium, but little sodium.  The imbalance between the two result in declining health; thus the need   to ingest more sodium.  The hard   to digest leaves and bark are broken down by enzymes secreted by bacteria   found in a very long evolved intestine, large caecum, and protracted   food-passage time.  These bacteria   are found in a number of herbivores.  Because   these enzymes act slowly, the porcupine has evolved this long digestive   system.  
Home Range: Winter ranges are much   smaller than summer ranges.  Nowak reports an Adirondack study finding 18.5 acres in winter and 162 acres   in summer.  W/H reports 6 acres for winter range for both sexes, with 62   - 160 acres for a female's summer range and 75 - 370 acres for a males summer   range.  In Pennsylvania, winter and summer home range is more stable; in the range of   6 to 36 acres.   Wilson reports 13   to 35 for winter and summer ranges respectively.  Winter ranges expand with low snow depth.  Females do not overlap, whereas   males overlap extensively with one another and with several   females.  
Social Structure: Porcupines are   solitary except during breeding time during late fall and early winter and in   winter denning concentrations.  Males are extremely aggressive towards   other males during the breeding period.   Females are more territorial than males.  A dominance hierarchy determines male access to females.  Occasionally,   in northern habitats, several (of either or both sexes) will den together in   winter. Both males and females return to the same ranges year after year,   although the male ranges may shift from one year to another. Unusual among   mammals; among the juveniles, only the females disperse during the fall mating   season.  Among adults, males will   disperse.  Shedd relays a story   about Robert Brander, a National Park Service ecologist, who has done   extensive research on porcupines, documenting groups of porcupine (up to 12)   gathering in an old clearing in mid-to-late summer.  It is believed that this was a social activity, occurring about a month   before mating, with the members being quite vocal.
Life Cycle: The extremely long   gestation period (205 to 216 days, with no delayed implantation or   fertilization) enables only one litter of usually just one precocial per year,   born in April through June (mating from September to December). See   remarks below for mating rituals.  Females   are polyestrous, recycling every 25-30 days, in heat for only 8 to 12 hours, and will aggressively attack non-attentive   males during this short fertile period.  At birth, the   quills are soft, hardening in about an hour. Young can climb trees within   hours after birth. Porcupettes (I donï¿½t make it up) wander off from the   mother at about six months. Breeds generally at one and a half years (fall of   the second year).  Wilson says females can breed at one year; males in two and a   half.  Nowak reports sexual maturity is   reached at approximately 2.5 years, although some males are capable of mating   at 16 months.  Life span of 12-18 years (NAS says 7-8 years).
Dens/Nest:   Multiple dens are kept in hollow logs, rock   piles, caves, crevices and abandoned buildings. 70% of dens in the Catskills were in rock   fissures at least 12' deep.  Doesn't   actually make a nest, nor is denning material used.  In these narrow rock crevices, the animals sleep in a sitting position.  The only sign is the numerous scats produced in the order of 75 to 200,   which are voided in the den, creating a deep deposition layer over time.  Is known to spend winter in a "station tree" of spruce or   hemlock when dens are not available.  Dens   are often used for many consecutive years.  However, multiple temporary shelters supplement the main   habitation.  A change of winter dens occurs   every three weeks or so (for unknown reasons).  One abandoned house in   New Hampshire provided dens for six porcupines; two in the chimney and one in   each of the four bake ovens!
Tracks: Five rear toes (1 1/2" w x 3 1/2" l) and four front toes (1 1/4"w x 3" l).  (These measurements include the claws.)  6" stride and 8" straddle.  The porcupine makes a runway through vegetation and may wear a distinct path   from the den to the feeding area.
Scat: Brown, crescent-shaped   droppings, often in large piles inside and outside the den entrance.
Can   be variable, often like deer.
Remarks:   The pelt of the porcupine gives a black and white appearance, similar to the   skunk; a warning sign to potential predators.  Porcupines also emit a unique, pungent odor, which can cause the eyes   to water and the nose to run. 
In   addition to the normal underfur and long guard hair, porcupine are afforded protection by 30,000   very long modified hairs, known as quills.  Like the skunk, the porcupine evolved natural protective qualities that   enable both these   creatures to adopt a slow, deliberate life style.   Porcupine cannot shoot quills against predators, but the quills easily   come out of the porcupine's body.  The   hollow quills have scales along the tips with raised edges pointing toward the   rear, which work like barbs, piercing into predator flesh at a rate of 1" a day. Quills have been known to work completely through an animalsï¿½ body,   rarely puncturing a vital organ, killing the animal.  Cutting off the ends will decrease this rate (Shedd says cutting off   the ends will make matters worse, since it leaves less quill to grip with   pliers, and may splinter the quill as well). The quills are found in highest   density on its back and the upper surface of it's tail and longest on its   upper shoulders. 
In   addition, the porcupine can produce a strong, pungent odor, which can cause   eyes and nose to water.
Porcupine   are preyed upon by fisher, who especially favor porcupine.  Fisher attack the porcupine by biting the face numerous times, weakening the   animal to the point that the fisher can roll the prey over and attack the   vulnerable belly.  Fishers reintroduced into the Catskills and the Ottawa National Forest   of Michigan have decimated the porcupine populations.  Other predators include wolverine, cougar, great horned owls and   bobcat.  Porcupines have a fondness for the minerals found in antlers   (and the salt from roads - leading to frequent road kills).
One   article basically says,  "If   you want to be desirable mate for a female porcupine, first you have to   perform a "three-legged dance" while whining a special serenade. It   helps if you can hold your genitals with your forepaw (or rub them with a   stick) while dancing. Finally, you shower your intended with urine. At which   point you can very carefully mount   your mate in the traditional manner.
"
Many   skeletal remains show signs of healed fractures, presumably the result of   falls from broken thin tree limbs (35% of 45 specimens showed healed fractures   in one study). 
In   addition to numerous fatalities from the quills reported to dogs, owls,   cattle, and horse, one human fatality has been recorded as the indirect result   of eating a porcupine meat sandwich containing a quill (OW!!!).