The term shrimp is used to refer to some decapod crustaceans, although the exact animals covered can vary. Used broadly, it may cover any of the groups with elongated bodies and a primarily swimming mode of locomotion – most commonly Caridea and Dendrobranchiata. In some fields, however, the term is used more narrowly, and may be restricted to Caridea, to smaller species of either group, or to only the marine species. Under the broader definition, shrimp may be synonymous with prawn, covering stalk-eyed swimming crustaceans with long narrow muscular tails (abdomens), long whiskers (antennae), and slender legs. Any small crustacean which resembles a shrimp tends to be called one. They swim forward by paddling with swimmerets on the underside of their abdomens, although their escape response is typically repeated flicks with the tail driving them backwards very quickly. Crabs and lobsters have strong walking legs, whereas shrimp have thin fragile legs which they use primarily for perching.
Shrimp are widespread and abundant. There are thousands of species adapted to a wide range of habitats. They can be found feeding near the seafloor on most coasts and estuaries, as well as in rivers and lakes.
