When a shark attacks a human, on average less than 10% of cases are fatal. It is often heard that the predator simply does not like the taste and smell of humans, so after biting him once, the shark simply swims away, not wanting to continue such an unpalatable meal.
When a shark attacks a human it does so quite deliberately, not confusing its silhouette with a sea lion or other sea creature . Over millions of years of evolution nature has made a shark almost a perfect killing machine, which can sense the electromagnetic field of the victim, is able to capture the smell, even if there is 1 molecule per 25 million in the water, has extremely sharp eyesight and excellent hearing. It is unlikely that such a formidable predator can simply mistake a human for a fish. This is confirmed by numerous studies of the bites that the shark leaves on people and on other sea creatures: they differ significantly in their character, indicating that sharks understand perfectly well whom they are attacking.
Experts agree that sharks really do not like to eat human meat. Mainly because of its composition, which is very different from the usual fish. However, no predator in the harsh conditions of the wild will pass up the opportunity to eat fresh prey because he does not like its taste too much.
A shark attacks a human for another reason: curiosity. Having never dealt with humans, the shark uses its teeth like a human uses his hands when touching an unfamiliar thing. A shark that bites a floundering swimmer in the water would probably not like human meat because of its low caloric content and lack of a lot of fat, but it would still continue to eat the human, if not for one reason. Like any other creature, the shark has an instinct for self-preservation. A man attacked by a shark has a habit of fighting desperately for his life, and sensitive shark eyes are within reach of his hands and feet. Again, if human meat were caloric and unusually tasty, the shark would choose to eat the victim, despite the risks of serious eye injury. But when it is possible to find better food in the sea and not get hit back, the shark, weighing the risks, will choose to swim away from the desperately fighting human.
It turns out that sharks really don't like the taste and composition of human meat, but this is not a factor stopping the predator from eating its prey. The resistance of the man himself, plus the cautious factor on the part of the shark, is exactly what often saves swimmers from being killed in the water. Whether an injured person can make it to shore without losing consciousness is another matter.