<P> 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 . </P> <P> 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 . To escape predators, some species flip off the seafloor and dive into the sediment . They usually live from one to seven years . Shrimp are often solitary, though they can form large schools during the spawning season . </P> <P> They play important roles in the food chain and are an important food source for larger animals ranging from fish to whales . The muscular tails of many shrimp are edible to humans, and they are widely caught and farmed for human consumption . Commercial shrimp species support an industry worth 50 billion dollars a year, and in 2010 the total commercial production of shrimp was nearly 7 million tonnes . Shrimp farming became more prevalent during the 1980s, particularly in China, and by 2007 the harvest from shrimp farms exceeded the capture of wild shrimp . There are significant issues with excessive bycatch when shrimp are captured in the wild, and with pollution damage done to estuaries when they are used to support shrimp farming . Many shrimp species are small as the term shrimp suggests, about 2 cm (0.79 in) long, but some shrimp exceed 25 cm (9.8 in). Larger shrimp are more likely to be targeted commercially, and are often referred to as prawns, particularly in Britain . </P>

Where do small shrimps hide to avoid predation