Some even live in fresh tropical water. They do not live right in the middle of the ocean. There are many, different types of shark. Some of them are the tiger shark, great white, blue shark, nurse shark, and a whale shark. Sharks eat tuna, plankton, sardines, herring, small fish, and other sharks.
Some sharks even eat swordfish.
Sharks do not have bones. They have cartilage. Cartilage is a rubbery lightweight material. A shark's spinal column is made stronger with calcium layers. Sharks have at least five rows of teeth.