Cancers hermits are carried to family of decapoda of Crustacea. The average sizes of an individual - 9-10 cm, the largest representatives reach 17 cm in length. More than 450 species of such crayfish are known.
External characteristics
Body of crayfish hermits mainly soft, they have no strong armor therefore the majority of types protect the paunch by means of empty sinks of mollusks. With them they hunt, in them and take refuge in a danger case. Three pairs of extremities, including claws usually stick out of a sink. The left claw cancer hunts, and right protects an entrance to a sink. In the course of evolution at hermits the back pair of paws was strongly truncated. Them now they also hold a sink at movement.
HabitatsCancers hermits meet in waters of the Baltic, Northern, Mediterranean seas, at islands of the Caribbean Sea, on the coasts of Europe. As a rule, they choose shallow water and only some types, prefer depth of 70-80 meters.
Food
Cancers hermits - predators. They eat mollusks, worms, other Crustacea. Besides, they are deathbirds. Eating up remains, the animals decaying at coast, crayfish thereby promote maintenance of purity in the territory of the dwelling.
Sink of crayfish hermits
As the shelter the crayfish hermits choose to themselves sinks about 25 species of mollusks. Without them they are very vulnerable and easily fall prey of predators. The main selection criterion is the relation of internal volume to sink weight. As cancer hermit grows constantly, it regularly is in search of a new sink. Usually right after a molt it begins to look for to itself(himself) more spacious house. If where he lives sinks much, then and process of replacement happens quickly and without problems. And here if there are no sinks, then cancer hermit looks narrowly at other same crayfish. If finds someone at whom a sink obviously not by the size, then special percussions it offers the fellow exchange. In case of consent the neighbor gets out of a sink. However if something does not suit it, then cancer hermit blocks an entrance a claw. Very often between crayfish there are real fights for a cozy living space.
Symbiosis of crayfish hermits and actinium
Very often crayfish hermits lodge on a sink actinium which protect them from enemies. Actinium in turn very quickly moves together with them in search of production. Actinium have poisonous tentacles which will paralyze the victim. Some crayfish prefer to lodge to actinium directly on a claw which they block an entrance to a sink at danger. If it is necessary to change a sink, then cancer hermit carefully of claws moves the neighbor to the new house. Very often the crayfish hermits who did not find to themselves a sink settle to actinium directly on the body.