The Australian land hermit crab (''Coenobita variabilis'') is a terrestrial

hermit crab Hermit crabs are anomuran decapod crustaceans of the superfamily Paguroidea that have adapted to occupy empty scavenged mollusc shells to protect their fragile exoskeletons. There are over 800 species of hermit crab, most of which possess an as ...

species, native to Australia. It is a nocturnal, omnivorous crustacean. They are gregarious and thrive in tropical areas near water.

Distribution

The Australian land hermit crab is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

to northern parts of Australia including northern

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

Northern Territory The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an Australian territory in the central and central northern regions of Australia. The Northern Territory shares its borders with Western Aust ...

and northern

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , establishe ...

Biology

The Australian land hermit crab (''Coenobita variabilis'') reaches a carapace length of . They closely resemble the Pacific hermit crab (''Coenobita compressus'') in appearance and they both have a shortened aquatic development stage. Australian land hermit crabs are light brown to pale brown in colour, with two dark ovals on the front of the head. Their eyestalks are long and are the same colour as the body. Each claw has a dark vertical stripe. They have dark brown spots all over the legs. The abdomen is short and fat.

Shell preference

The preferred seashells of ''C. variabilis'' include '' Babylonia'', ''

Nerita ''Nerita'' is a genus of medium-sized to small sea snails with a gill and an operculum, marine gastropod molluscs in the subfamily Neritinae of the family Neritidae, the nerites.MolluscaBase eds. (2021). MolluscaBase. Nerita Linnaeus, 1758. A ...

'', '' Phasianella'', '' Thais'', '' Tonna'' and ''

Turban A turban (from Persian دولبند‌, ''dulband''; via Middle French ''turbant'') is a type of headwear based on cloth winding. Featuring many variations, it is worn as customary headwear by people of various cultures. Communities with promin ...

seashells A seashell or sea shell, also known simply as a shell, is a hard, protective outer layer usually created by an animal or organism that lives in the sea. The shell is part of the body of the animal. Empty seashells are often found washe ...

. They are also found to be fond of several varieties of land snail shells such as Aratan snail and rice snail. As the hermit crabs grow, they must exchange their shell for a larger one. Since intact gastropod shells are not an unlimited resource, there is frequently strong competition for the available shells, with hermit crabs fighting over shells. The availability of empty shells depends on the abundance of the gastropods and hermit crabs, but most importantly on the frequency of organisms that prey on gastropods but leave the shells intact. A hermit crab with a shell which is too tight cannot grow as fast as hermit crabs with well-fitting shells, and is more likely to be eaten. Although hermit crabs need to change shells regularly, they will not abandon their old shell unless they have a larger and newer one to change into and unless they feel safe.

Distribution

Biology

Shell preference

References

Further reading