Hermit crabs are widely known for their scavenging shell they carry, These are fascinating specimens for zoologists because of their intelligent selection of suitable shells as their ‘home'. When a new, bigger shell becomes available, hermit crabs gather around it and form a kind of queue from largest to smallest. When the largest crab moves into the new shell, the second biggest crab moves into the newly vacated shell, thereby making its previous shell available to the third crab, and so on.