crabs life styles and video pictures gallery

Tuesday, September 1, 2009

crabs life styles and video pictures gallery

Crabs are related to lobsters and shrimps. However, they have evolved so that they can walk or run sideways, as well as burrow and swim. The body is covered by a chitinous shell called a carapace. A crabs abdomen has become fairly reduced and is tucked under the body. "This reduction is greatest among the true crabs, which lack the flaplike tail of the hermit crabs and their allies; instead, the abdomen serves as a brood pouch for the eggs. A crab's segmented body has several pairs of appendages, of which usually five pairs serve as walking legs and two as sensory antennae."(1) The pincers, called chelae, are located on the front legs ans are used for fighting, display, and feeding. Crabs can possess fairly complicated nervous systems and are considered to be more advanced. They can live in more extreme areas because of their ability to adapt well to the changing environment. Crabs can see fairly well with their compound eyes; their senses of smell and taste are also more advanced which helps them to find food and mates easier. "Reproductive and social behavior sometimes include complex mating rituals and communication techniques such as drumming or waving the pincers.