These crabs have long spirally curved soft abdomens which are hidden in an empty gastropod shell (sea snails) which is carried by the crabs around. The shell, in which the crab can entirely retreat, is used as a protection from predators. Some species use immobile structures as 'homes'.
The Cook Islands is an islandic country in South Pacific Ocean, it comprises 15 islands with the total area of 240 square kilometres. The country is in free association with New Zealand which is responsible for the Cook Islands' defence and foreign affairs. Official languages are English and Cook Islands Māori.