Crayfish move underwater by fluttering small appendages, called swimmerets; but, they can also use their legs to walk on land or on the floor of various bodies of water. Swimmerets are located underneath the tail and can be used to clutch eggs.
Crayfish physically resemble lobsters and live in freshwater. The crayfish is an opportunistic feeder, preying on smaller, slower animals it can catch or scavenging off of dead ones. Plants are also included in its diet. Most species of crayfish are found in North America, with a population of more than 330 species. The crayfish is an important part of cuisine worldwide, and it is also commonly used as fishing bait. In certain areas, such as the United Kingdom, some species of crayfish are considered invasive, because they threaten local ecosystems.