In Life of Pi, what are some reasons that prove that humans are the most dangerous animals?

When Pi first introduces the belief that man is the most dangerous among all animals, he discusses what zoos around the world have to deal with when visitors interact with the animals. Humans are not only disrespectful to a zoo's animals, but they can be deadly. For example, in chapter 8, Pi lists many things that visitors have done to innocent zoo animals throughout the years. Part of that list is as follows:

". . . we have in mind people who feed fishhooks to the otters, razors to the bears, apples with small nails in them to the elephants and hardware variations on the theme: ballpoint pens, paper clips, safety pins, rubber bands, combs, coffee spoons . . . " (29).

The list goes on after that, too. Then he lists all the types of animals who have died because of such cruelty.

The worst that humans become, though, is demonstrated when they act like wild animals for survival's sake. It's as if all rules of human decency fly out the window when people face imminent death. The cook is the worst example of a dangerous animal because he cuts off the leg of the sailor without flinching. Also, humans can lie to achieve their wicked goals, which is exactly what the cook does to get Pi and his mother to help him amputate the leg:

"It was the cook's idea. He was a brute. He dominated us . . . I can still hear his evil whisper. He would do the job to save the sailor's life, he said, but we would have to hold him" (304-305).

The evil whisper shows the character of the cook. When Pi and his mother discover that the amputation was for fish bait, rather than to save the sailor's life, they are heartbroken because of such betrayal and evil.

One more example of how humans are the most dangerous animals is when they become cannibals. Other than a hyena, who accidentally eats parts of another hyena during a hunt, not many animals eat their own kind. The cook not only dissects the sailor and eats his flesh, but he also kills Pi's mother and feeds her to the fish. Curiously, though, after the cook kills Pi's mother, his mouth is bloody after throwing her body overboard (311). The cook, therefore, is the epitome of how humans can be the most dangerous animals in the world.