To protect their soft back end, hermit crabs need a tool—a shell that has been discarded by another animal. As a crab grows, it must find, examine and test out a new, larger shell. It has to determine if this tool will be a good fit, and fast. A hermit crab cannot survive for long without its shell.
Do hermit crabs ‘think’ when they try a new home on for size? The answer, in most cases, is likely no. While hermit crabs can determine the size of a shell, they usually don’t have the flexibility to follow Plan B or Plan C if a new shell isn’t a good match.
That being said, an interesting behavior has been documented in the wild. When a hermit crab happens upon an empty, discarded shell, it will examine it to see if it is a good fit. If it is not, the hermit crab may wait for others to find the discarded shell. As other crabs approach, they take turns testing the shell, one by one. If the hermit crab waits while others swap shells, it just might get lucky and find a new, larger shell for itself!
As with all the animals at the Smithsonian’s National Zoo, our hermit crabs receive the highest quality of care. When their shells are feeling snug, they have a plethora of new homes to choose from.
A big part of caring for animals is doing research, and that includes reading up on the latest animal care studies, husbandry techniques and exhibit innovations. As part of his summer internship with the primate team, Noah Goldfarb researched hermit crab biology, behavior and husbandry, and he helped inform some exciting new changes made to our hermit crabs’ habitat!
We are all about training the next generation of conservationists, and it was rewarding for our whole team to come together and help advance the care of these charismatic crustaceans.