Most of the more than 400 species of shark eat fish, including herring, anchovy, stingray, tuna, flounder and other sharks. With sharp eyesight, a keen sense of smell and excellent hearing, sharks are adept at finding prey, but their diet varies, depending on what is available at the time.

Sharks that eat fish may also eat other marine life, and some species of shark do not eat fish. Species that fall into the filter feeder category, such as basking sharks, eat plankton, which are tiny organisms floating in the water. A filter feeder takes plankton-filled water into its mouth and expels only the water from its gills. Shark species that live close to the ocean floor, such as nurse and angel sharks, eat small fish but also enjoy crustaceans and mollusks. Bony fish are a favorite of bull and blue sharks. These predators are less picky about their diet, which includes other sharks. Great white sharks are also known to eat other shark species. Their diet includes larger fish and mammals, such as sea lions, small whales, sea turtles and sea birds. Humans are not typically part of a shark’s diet but great whites, tiger sharks and bull sharks are the most likely species to attack humans.