Hermit crabs and other related creatures are included in the infraorder Anomura, within the order Decapoda. Hermit crabs are well known for their curious habit of colonizing empty gastropod shells to protect their soft-skinned abdomens. About 45 species occur around South Africa.
Anomura drives from an old classification in which decapods were divided into three categories : Macrura (long-tailed), Brachyura (short-tailed) and Anomura (differently-tailed).
To fit the spiral of their adopted homes, the abdomen has become twisted and the appendages on the inside of the curve reduced in number or lost. As decapods, Anomurans have ten ‘legs’ (i.e., pereiopods). The first pair of legs bears nippers, the left one often being enlarged to seal the opening of the shell when the crab withdraws. The second and third pairs of legs are used for walking, while the last two pairs are reduced to grip the shell. The last pair of leg is often hidden inside the gill chamber, under the carapace, to be used for cleaning gills.
As they grow, hermit crabs have to move into progressively larger homes, and they often fight for the best shells. Most species are scavengers, but some filter food particles from the water using their antennae.
F*CK FISH 