Shrimp

A shrimp is a small sea animal with a hard outer shell, ten legs, and a long, curved body. Shrimp belong to a group of animals called crustaceans, which also includes crabs and lobsters. They live in oceans, rivers, and lakes all over the world. There are more than 2,000 different kinds of shrimp, from tiny ones the size of a grain of rice to giants nearly a foot long.

A shrimp's body has three main parts: a head, a thorax (middle), and a long tail. Its shell is not bone. It is made of a tough material called chitin, the same stuff that makes up insect shells. As a shrimp grows, it sheds this shell and grows a new, bigger one. A shrimp can do this many times during its life.

Shrimp swim by flipping their tails. When a shrimp wants to get away fast, it snaps its tail under its body and shoots backward through the water. This is called the tail-flip escape. Shrimp also have tiny legs called swimmerets on the underside of the tail. These help them move more slowly and steer.

Most shrimp eat almost anything they can find: dead plants, tiny animals, algae, and bits of food floating in the water. This makes them important cleaners of the ocean floor. In turn, shrimp are food for a huge list of animals. Fish, whales, seabirds, squid, and octopuses all eat shrimp. So do people. Shrimp are one of the most popular seafoods in the world.

Some shrimp have strange and amazing jobs. Cleaner shrimp set up little "cleaning stations" on coral reefs. Fish line up and wait their turn. The shrimp climbs into the fish's mouth and picks off dead skin and parasites, and the fish does not eat the shrimp. Pistol shrimp have one giant claw that snaps shut so fast it makes a loud popping sound. The snap stuns small fish from several inches away.

The mantis shrimp may be the most surprising of all, though it is not a true shrimp. It has the best eyesight known in the animal kingdom. Humans see color using three types of cells in the eye. A mantis shrimp has sixteen. Scientists are still trying to figure out exactly how the mantis shrimp's brain uses all that information, because no other animal sees the world quite the same way.