Okay, this is the way I had it explained to me by a marine biologist at the Sydney Aquarium a couple of years ago. He said that sharks are primarily creatures of instinct, and they don't have a lot of brain power. They are born knowing almost everything they need to know. Now, instinct by its evolutionary nature takes a looong time to alter, usually on the order of many generations (if not much more!). And how long have divers been on the scene? 50 or 60 years maybe? ( I am discounting early free divers for now, due the limited numbers of them, the limited areas of exposure, and the relatively brief exposure times.) That is hardly enough to make a dent in the instinctual process. The upshot of this is, most sharks at depth simply don't know what we are. Divers don't compute, to them. And, unless you do something really stupid ( which accesses one of their instinctual responses, like trying to grab the tail of one:11: , or dragging bloody fish behind you ), they really don't know what to do about you. I have had several big sharks, including a couple of 10 foot tigers, cruise right by me to look me over, but never had one come within touching range. (Nice pictures, though.)
When you look at actual shark attacks, where are the overwhelming majority of them located? In very shallow water, or to a lesser degree, at the surface. This is where sharks have been interacting with humans for millenia. They KNOW what we are here. Although, even then, most of the attacks I have researched have been probable cases of mistaken identity. Murky water which limits visibility, other targets in the water close by, etc. Sure, some attacks don't fit these parameters, but hey, life is full of uncertainties and little mysteries. I'm just going with the numbers here. By and large, this is the way I had it explained to me, and it sure seems to fit the available data. I am sure that others have differing views, and I'm sure we are going to hear from a few now. But isn't that the point of this board? Sorry this was so long, but I just had to get my 2 cents worth out. Thanks for listening. Woody