10 myths about sharks: the truth - Australian Geographic
Great White Shark (Photo: Getty Images)
10 myths about sharks: the truth
BY Valerie Taylor |
June 23, 2009
Sharks: evil or misunderstood? An AG Society 'Lifetime of Conservation' awardee Valerie Taylor separates truth from tall tales.
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I'M OFTEN REFERRED TO as a scientist. I’m not. I write from 50 years of experience. The oceans have been very good to my husband Ron and me. They’ve given us a life of excitement and adventure. The marine world is my teacher, my workplace and my love, yet Ron and I have but dabbled in what it offers – unknown depths, and their mysterious creatures, covering 72 per cent of our planet’s surface.
Ron and I learnt very early that footage of sharks would sell more readily than that of any other marine animal. In the 1950s Movietone News (an international cinema-shown newsreel covering the years 1929–79) bought Ron’s 16 mm footage, blew it up to 35 mm and showed it in theatres around the world. Then came television (in 1956 in Australia) and the public’s lust for any images of sharks had us searching offshore waters for these “dangerous” predators. For us, filming sharks in their natural environment became a way of life.
There’s no one way to describe sharks. There are hundreds of species, all with different characteristics, but few of them are potentially dangerous to humans.
The most threatening species cruising our coastline is the great white shark. The largest recorded great white was caught in 1978 off the Azores, a Portuguese archipelago in the Atlantic Ocean, roughly 1500 km from Lisbon. It was measured by an observer at 8.8 m and was estimated to weigh more than 4.5 tonnes. Claims of much larger great whites being caught are unsubstantiated. In fact, I’m not even sure I believe the size of the Azores specimen, but the ocean is full of surprises and a super-sized shark could well be one of them.
Other potentially dangerous sharks along our coast are mostly of the genus Carcharhinus: bull sharks, bronze whalers, Galapagos and, in the tropics, the grey reef, silvertip and the tiger. Several other species of shark can become excited when there’s food in the water, and spearfishermen have even been bitten by metre-long whitetips when handling a struggling, bleeding fish. I’ve been bitten several times and always when there was food in the water. I never blamed the shark, only myself for being careless.
In the 1950s and early 1960s we believed what the media said – that the only good shark is a dead one and when you see a shark, it’s either you or it. Our 50 years of experience has allowed us to separate the fact from this fiction.
1. TRUE: Sharks can be stared down
While filming Blue Water, White Death in 1969, 200 km off the South African coast, we left the safety of our cages, which we tied to a dead whale, and fought off hundreds of large sharks, eventually making a place for ourselves in the midst of the pack. We taught those sharks, all of them extremely dangerous, respect in a few frantic minutes.
The first beasts to approach us were hit by my shark billy (a 1.2-m long wooden club with a blunt end), bashed by Ron’s metal camera housing, or punched in the gills by fellow cameramen Stan Waterman and Peter Gimble. When they bumped us, we bumped them back harder. Not one of us backed off. I waited to be bitten, torn apart, or to see my companions torn apart, and wondered what I would do when it happened. There was no fear, just a feeling of excitement and aggression.
It was like rewinding time. We had entered a primeval world, unchanged in millions of years, and made a place for ourselves at the banquet. Somehow the knowledge spread throughout the shark pack that if confronted, these four bubble-blowing, clumsy creatures would fight. Apex predators are used to their prey trying to escape, not standing their ground and fighting back.
But we fought back and became accepted as part of the pack. Surrounded by very dangerous sharks, we swam with them, even to where they were feeding on the whale and although we were sometimes pushed aside, we did not again feel threatened.
If a swimmer or diver should confront a shark and see no fast route of escape, my advice is to look the fish straight in the eye, scream, swim towards it, show extreme aggression and – if contact is made – fight like hell. Most shark attack victims never see the shark before being bitten. Once you’ve seen the shark, you’re unlikely to have any problems – except confronting your own fear.
2. TRUE: Sharks are attracted to swimming dogs
Sharks’ curiosity attracts them to any unusual creature in their environment. A small animal like a dog is more likely to be considered prey than a big animal.
3. PLAUSIBLE: Sharks are attracted by blood
It has been said that human blood will attract a shark from kilometres away. This hasn’t been our experience, but perhaps we’ve never bled enough to be attractive. We know that a harpooned whale bleeding its life into the open ocean as it cries in agony can attract hundreds of large, very dangerous sharks.
Much to the horror of sailors in the water after vessels have sunk, oceanic whitetip, blue and silky sharks can appear like magic from the depths. The former two have no instinctive fear of humans; they have evolved to eat large, wounded or thrashing animals in the water and are responsible for more human deaths than all the other so-called dangerous sharks worldwide. Like many other sharks, they can be trained, and quickly.
4. FALSE: Sharks must turn on their side to bite
Sharks do not have to be on their side or back when feeding; they can bite from any angle.
5. TRUE: Sharks can be trained
Sharks are easily taught a simple action. I once trained a whitetip reef shark to swim towards me over a piece of pink coral. When she did it correctly I rewarded her with a piece of fish. When she swam towards me any other way I hit her on the head. Within 45 minutes I had that shark performing exactly as I wanted.
Several hours later I returned to the same place with my camera. I now had three whitetips swimming over the pink coral. Somehow my trained shark had let her companions know that if they behaved in a certain way they would be given a treat. This isn’t an isolated case but something we’ve done many times, not only with sharks but fish as well. Sharks have a very small brain but, unlike humans, they probably use all of it. We’ve found they can learn a food-related trick much faster than a dog, bird or cat.
6. FALSE: Sharks swim backwards
We’re constantly asked this question and the answer is no, although there are a few species, including the epaulette shark, found in tropical Australian waters from northern NSW to Shark Bay, WA, that can “walk” backwards.
7. PLAUSIBLE: Attacks are more likely at dusk
Bull sharks have bitten and killed people wading or standing in water. They come into the shallows on a rising tide looking for anything edible that may float off the shore.
Wading or swimming near a channel where fish are frequently cleaned, or where the water is murky, is not advisable, particularly at dusk when some sharks (for example the bull) are conditioned to feed.
8. FALSE: Sharks cannot survive in fresh water
Bull sharks will swim up rivers into brackish or even fresh water, especially females when they are ready to pup. Although most sharks have sharp eyesight, rivers can be murky. In low visibility conditions, sharks investigate anything unusual with their teeth. A gentle nibble of a shark’s razor-sharp teeth can be fatal, however, for a thin-skinned human.
9. FALSE: Sharks must keep moving in order to survive
This was once widely thought to be true, but it isn’t. Most sharks can rest on the bottom and pump water over their gills. The lovely and endangered Australian grey nurse shark can hang almost stationary in the water. They’re often seen resting in groups, waiting to go out and forage under the cover of darkness.
10. TRUE: Sharks have a natural hierarchy
With sharks, as with most animals, if you are larger and better-armed than your companions you’ll generally have right of way. At Shark Reef off Pacific Harbour in Fiji, we’ve witnessed a big tiger shark scatter a group of feeding bull sharks despite the latter being very large themselves. On one occasion, however, the bulls joined forces and out-muscled the tiger. Shark Reef is the only place we know of where continual professional research into shark behaviour is carried out in their natural environment. On any given day a diver can see between five and seven species of shark, each one trained by locals to feed in certain ways at different depths. For instance, the reef whitetip will not approach the baits where the bull sharks are being fed. The blacktip, whitetip and grey reef species are all fed in shallow water along the reef’s edge. The larger sharks are fed tuna heads at a depth of about 15 m. To see 20 or more bull sharks waiting in line for a tuna head while scientists record their gender, behaviour and any distinctive markings is truly an amazing experience.
Sharks are wonderful. To me they’re nature’s perfect creation. They inhabited this planet long before us, yet worldwide people are harvesting them in increasing numbers (approximately 100 million a year). The popularity of shark-fin soup has caused shark numbers to fall rapidly.
Shark finning – the brutal but lucrative practice of cutting fins off live sharks and throwing them back into the ocean to slowly drown – is banned in this country but Australia imports 10 tonnes of dried shark fins every year from countries that have not banned finning, including China and the Philippines, which equates to an estimated 26,000 sharks. Dried shark fins are widely available in Sydney’s Chinatown for up to $1400 a kilogram. A bowl of shark-fin soup costs more than $150.
It is tragic that the Queensland Government is considering giving commercial fishermen permission to harvest sharks – including for the shark-fin soup trade – in the waters of the Great Barrier Reef Marine Park. It’s like giving a game hunter permission to enter national parks to kill koalas for their skins – totally outrageous.
The harvesting of these wonderful animals won’t stop until it’s too late. As with all top predators, sharks are slow breeders; it can take up to 12 years for a female great white to reach sexual maturity and, once she does, she gives birth to one pup only once every three years. Sharks are already hard to come by and, tragically, I can foresee a day in the not too distant future when we won’t encounter them at all.
Source: Australian Geographic Jan - Mar 2009
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