Crabs are crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail". are generally covered with a thick exoskeleton, and armed with a single pair of chelae (claws). Crabs are found in all of the world's oceans. Additionally, there are also many freshwater and terrestrial crabs, particularly in tropical regions. Crabs vary in size from the pea crab, only a few millimetres wide, to the Japanese spider crab, with a leg span of up to 4 m. Some gourmets prefer these soft-shelled crabs, claiming they are more succulent and sweet.