Saturday, 25 May 2013
Sharks Lack the Bite Reflex we know in Mammals
During my seven year study of the behaviour of wild reef sharks, I had many opportunities to observe them under circumstances in which I expected them to bite, as a dog or other mammal would tend to do. Yet they did not. Further, while the sharks had preferred companions, I never saw them fighting with each other. They appeared to have friends, but no enemies.
For years people had told me, and I half believed myself, that one day I would be bitten and would bleed to death, or faint and drown. Since I was alone far from shore as night was falling, I could expect no one to save me. These circumstances enhanced what appeared to be an instinctive tendency to react with darkening consciousness and soaring terror to certain visual cues. So I had long acquaintance with the phenomenon of fear. Often it took all my psychological force to compose my mind in order to overcome it.
When things went wrong, I would find myself in tossing waters opaque with blood and excited sharks, in a situation for which I was unprepared. Yet, no matter what happened, no shark bit me, time after time.
All other species, wild and tame, with whom I had a fraction of the intimacy I shared with sharks had bitten me sooner or later, either by accident or in a fit of pique. Even my pet dog sometimes grabbed my hand in her teeth along with the offered cookie.
Why had none of those hundreds of sharks of four different species, some many times my size, ever bitten me? I would watch Martha, my favourite, coil through the sea in front of my face, snapping up the treats I was freeing for her while ignoring my hands and the little plastic bag I had brought them in, and be convinced that it could not be a random coincidence.
There had to be a reason.
One night I accidentally kicked a shark with all my force, not realizing that the six foot animal was between my legs as I finned upward to reach into my kayak. Horrified, I peered underwater to scrutinize the situation, expecting her to instantly turn and slash. But there was no change in either her speed nor trajectory as she curved around to lazily circle me.
It was then that I realized that I was expecting a reaction from a shark that was based on my experiences with mammals. As mammals, we share the automatic biting reflex displayed by dogs, cats, primates, rats, and even vegetarian mammals. Anyone who has been seriously assaulted knows that the instinct to bite in self defence is very thinly veiled beneath our civilized daily lives. It is an automatic reflex that we take for granted.
But that night, I realized that these requiem sharks must lack this bite reflex.
Our fear of sharks is based on the intrinsic knowledge that we, and animals like us, instinctively bite in aggression or fear. We just naturally assume that sharks will too.
But they don't.
Sharks do not share this biting reflex with us, and that is the missing key. With their big mouths and shocking sets of teeth, our imaginations are undone as we consider them opening to bite us. But in fact, they bite only to eat, not to injure another animal.
On the contrary, they seem to have an inborn inhibition against biting companion animals. They don't regard us as prey, so they apparently view us as other animals who share their ecological community.
Even the great white shark has been shown by Dr. Peter Klimley to ritualize conflict when ownership of a seal prey comes into question. The shark who can splash water farthest with its tail wins the seal, so a physical battle, which would gravely harm both sharks, given their dentition, is avoided.
Unfortunately, our instinctive fear has been used by the media to entertain us with horror shows, starring sharks as the only known monsters in the sea. The wide spread shark attack hysteria that has resulted from years of such misrepresentation of sharks is one of the great obstacles to shark protection. Examples are the movie "Jaws" and Discovery Channel's highly profitable annual "Shark Week."
Given the numbers of people using the oceans for recreation, it is actually remarkable that so few are accidentally bitten by members of this highly evolved and intelligent, predatorial class of animals. Far more people are bitten to death by cats and dogs, slain by lightning or falling coconuts, or murdered by their own species.
For further information, my book "My Sunset Rendezvous : Crisis in Tahiti" meticulously describes the counter-intuitive behaviour the sharks displayed with me underwater, over the 15 years that I spent observing them in French Polynesia.
Ila France Porcher