Most sharks have five to fifteen parallel rows of teeth made of hard, ivory-like bone used for biting and tearing, not for chewing.
Sharks swallow their food whole or in big chunks.
Several rows of replacement teeth develop continuously throughout the shark's life, positioned behind the first row of working teeth. Sharks lose and replace teeth throughout life, unlike humans, and the teeth grow from a membrane called a tooth bed. Teeth are replaced, usually one at a time, about every 9-21 days. Studies by Mote scientists have shown that, on average, a nurse shark will replace each front-row tooth every ten days to two weeks in summer when actively feeding, and every one to two months when they are less active in winter. The shape and size of the jaw and teeth also indicates specialized feeding for some sharks.