Biology
Although its head, thorax and pincers are covered with a carapace, the hermit crab has a soft underbelly. To protect itself, it lives in a gastropod mollusc shell that it withdraws into in case of danger, blocking the entrance with its often asymmetrical claws.
If a shell is too small, it very quickly finds another one, explores it and conscientiously cleans it before moving in. In order to grow, it also needs to shed its carapace.