Most sharks cruise at high speed when they swim. Sharks have peanut-sized brains and are incapable of learning. Shark meat is poisonous to people. All sharks have to swim constantly. Sharks have poor vision.
Sharks are hard to kill.
A shark is a shark is a shark. Sharks are trash fish. The biggest enemy to sharks is man. Sharks are a critical part of marine ecosystems, a source for knowledge to help the human condition, and the basis of a valuable fishery. Sharks' eyes, which are equipped to distinguish colors, employ a lens up to seven times as powerful as a human's, and some shark species can detect a light that is as much as ten times dimmer than the dimmest light the average person can see.