A 45 kilogram shark will eat the equivalent of three double hamburgers a day. Some sharks have lived for a year without eating, surviving on the oil stored in their livers. Most sharks are large. Sharks have a habit of eating people. However, if the bodies of all the sharks killed by humans in one year were stacked in a pile, it would weigh more than a billion pounds.
Sharks wander randomly through the ocean.
Sharks like to hunt alone. Dogfish sharks were so named because they swim in packs. Sharks are slow and cumbersome. Sharks appeared in the oceans after the dinosaurs. That makes them twice as old as dinosaurs and 100 times older than humans.