庞大凶猛鲨鱼也有克星吗

鲨鱼这样的食肉动物也会有失败的时候吗？答案是令人无比惊讶的，看了文章，你就一目了然了。

But when sunlight streams through the water producing glare, great whites have another ingenious solution. The same reflective plates are now swathed in a thin layer of pigment giving the shark a build-in pair of sun glasses.  

But every attack could put these delicate eyes in harm's way. Over millions of years, the great white has evolved a remarkable protection. When they come in for the kill, a shark's mouth opens wide and its eyes roll back into the skull shielding them from thrashing prey. So the great whites are built to protect their vital sensory systems, which may explain how Jake Karen survived its attack. When he fought back against the great white, the shark should have easily overwhelmed him. But somehow Jake survived.

How could this giant predator fail? The answer is surprising, great whites fail a lot. Research from South Africa shows on average Great Whites missed the mark over half the time. It's as if they know every attack is a gamble, so they proceed with caution. If the prey survives the initial bite and fights back, like Karen did, even a giant shark may leave hungry in order to feed another day.  

So Great Whites are designed to protect their all important senses from injury, none more so than their eyes. But what exactly does the Great White see?  

At Florida Atlantic University, this tiny lemon shark and its odd shaped bonnethead may reveal the answer. Doctor Steve Kargeror and graduate student Mickey McCone are preparing a high-tech experiment to discover a shark's field of view. First, they place the lemon shark in an anesthetic bath, putting it to sleep. A tiny hose keeps water flowing over the gills. Injecting a blue dye confirms the shark is breathing.

"What we found so far is that sharks really do have a pretty good sense of vision and in fact they have excellent low light vision. In terms of, comparing to other fishes, I think sharks are, you know definitely comparable, if not superior to many of the other fishes."