Fri May 14, 2010 4:57 pm
|
REPLY
QUOTE
TOP
|
|
Hermit crabs are decapod crustaceans of the superfamily Paguroidea. They are not closely related to true crabs. Hermit crabs are quite commonly seen in the intertidal zone: for example, in tide pools.
Most species have long, soft abdomens which are protected from predators by a salvaged empty seashell carried on the crab's back, into which the crab's whole body can retract. Most frequently hermit crabs use the shells of sea snails; the tip of the hermit crab's abdomen is adapted to clasp strongly onto the columella of the snail shell. As the hermit crab grows in size, it has to find a larger shell and abandon the previous one. This habit of living in a second hand shell gives rise to the popular name "hermit crab", by analogy to a hermit who lives alone.
Of about five hundred known species, most are aquatic and live in varying depths of saltwater, from shallow reefs and shorelines to deep sea bottoms. However, tropical areas host some terrestrials.
The king crabs in the family Lithodidae were formerly considered to be derived hermit crabs, but are now placed in a separate superfamily.
|
