Coenobitidae

Coenobitidae is the family of terrestrial hermit crabs, established by James Dwight Dana in 1851, found across tropical coastal regions worldwide and, despite living on land as adults, remaining dependent on the ocean for reproduction. The family comprises two genera and, by current counts, eighteen species in total: Coenobita and the monotypic Birgus, whose single species is the coconut crab. All members begin life as planktonic larvae at sea, passing through zoeal and then megalopa larval stages before settling; on settling, the young crabs take up gastropod shells and move inland, molting into their first true crab form, while adult females return to the ocean to release their eggs. Coenobitidae is unique among the hermit crabs for having achieved this successful transition to a fully terrestrial adult life.