Hermit crabs have a soft abdomen and they need to protect this soft part with an empty snail shell. As they grow, they have to search out larger snail shells.
True crabs have five pairs of legs including the claws.
Most hermit crabs live in the sea, but there are a few species that spend almost the whole of their life on land. These are the land hermit crabs of the family Coenobitidae. Sometimes they are on sale in pet shops. Even land hermit crabs must return to the sea to breed. The female crab discharges her eggs into the sea.