The number of walking appendages a crustacean has depends on the particular type of crustacean. Crabs and lobsters both have eight walking legs and two front claws. Shrimp have 10 jointed legs.
In addition to legs, crustaceans have other structures that give them mobility and allow them to capture prey. The crab has a claw structure known as a cheliped that is used for catching food. The lobster uses its tail to swim backwards and to escape from predators. Shrimp possess appendages in their abdomens known as swimmerets that enable them to move in water. They also use their tails to propel themselves in a backwards motion.