Crab
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 An Anemone crab
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Crabs are crustaceans. They have a very short tail. The tail might not be visible at all. Usually they have a very hard exoskeleton. This means they are well protected against predators. Crabs are armed with a single pair of claws. Crabs can be found in all the oceans. Some crabs also live in fresh water, or live completely on land. The smallest known crab is the pea crab. It is only a few millimeters wide. The biggest known crab is the Japanese spider crab. It lives in the Pacific, between 300 and 400 metres deep. The crabs that were found had a leg span of up to 4 metres, were up to 37 centimetres large, and had a weight of up to 20 kilograms.
Crabs are omnivores, they eat anything they find. Most often this is algae. It might also be molluscs, other crustaceans, worms, fungi and bacteria.
The closest relatives of the crabs are anomurans, a crustacean group which includes animals such as hermit crabs, king crabs and squat lobsters. They look a lot like crabs and many have the word "crab" in their name, but are not true crabs. Anomurans can be told apart by the number of legs: crabs have ten legs, including claws, while the last pair of an anomuran's legs is hidden inside the shell, so that only eight legs are visible.
A crab's tail is folded under its body.
