Our guide to hermit crabs should give you some of the facts you need to take proper care of your pet.
Hermit Crab Introduction
Land hermit crabs are a great choice of pet: exotic, clean, relatively inexpensive and easy to maintain, and as an bonus, they don’t have to take up much space.
However, they do have some basic requirements that need to be met if they’re going to thrive in captivity – the purpose of this site is to help hermit crab owners understand what those are and to offer some suggestions on the way to meet those demands.
Lies, All Lies!
Coenobita clypeatus Hermit crabs aren’t crabs at all. True crabs are crustaceans from the infra-order Brachyura, whereas all hermit crabs are from the infra-order Anamura and the superfamily Paguroidea. Biologically speaking, they’re much more closely related to lobster, crayfish, and shrimp than they are to true crabs. While most species of hermit crabs are aquatic, and can’t live very long outside the water, there are a few land-dwelling species.
Most notable among the land dwelling hermit crabs is the family Coenobitidae, which encompasses both the genus Coenobita, which contains the land hermit crabs most people keep as pets and the genus Birgus, the giant coconut crab.
The hermit crabs this web site focuses on are the members of the genus Coenobita. Several species in this genus are sold in the pet trade, though which are available varies widely by country. In the US it is common to find the following species (roughly in order of their prevalence in most areas): C. clypeatus (Purple Pinchers or Carribean Tree Crabs), C. rugosus (Ruggies), C. compressus (Ecuadorians), C. perlatus (Strawberries), C. brevimanus (Indos), and C. cavipes (Cavs).
Hermit crabs also are not hermits. In the wild, they tend to live and travel in large groups. This makes good survival sense, since as crabs grow, their former shells are automatically available to smaller members of the group, and shell swapping goes on down the line so that finding an appropriate shell at the appropriate time isn’t so unlikely.
This is why it’s best to always have at least two hermit crabs in a tank – if possible at least two of each species. They’re used to the company. Their name refers to the fact that they live alone in their little “house,” like a hermit living alone in a hermitage.
Land hermit crabs are not bred in captivity for the pet trade. Captive breeding land hermit crabs have been done, but it is not currently a commercially viable process, so all the hermit crabs found in pet stores are wild caught. While I don’t feel this necessarily precludes ethically buying hermit crabs, I do think it needs to be a consideration of how land hermit crabs are housed and fed in captivity.
They need – for both their enjoyment and their health – fresh foods in addition to the commercially available pet foods. No commercially available pet food is nutritiously complete enough that it should be hermit crabs’ only food option. They also require room to move around and things to climb on and hide under, so they can remain active and relatively unstressed.
Many pet stores will try to market hermit crabs as good animals to keep alone, or in a small plastic tank where there’s no room for even their basic room requirements, much less room for things for them to climb on and hide in. For an animal who is used to having entire beaches to roam, that’s a pretty stressful change.
What is a hermit crab’s lifespan?
When hermit crabs mate, they stretch their bodies fairly far out of their shell, and a male hermit crab passes his spermatophore into a female crab’s gonophores, fertilizing any eggs. Once the eggs are fertilized, the female hermit crab will attach the egg sac to her abdomen and keep it safe and moist inside her shell until she reaches the ocean.
When the expectant mother reaches the ocean, she releases her egg sac into a tidepool, and her extremely tiny, fully aquatic larvae hatch.
Land hermit crabs go through several molts in their aquatic stage before they ever even start to look like hermit crabs. When they are almost mature enough to come onto land, the hermit crabs start searching the ocean floor for tiny, tiny shells. Once they find one and come onto shore, they molt again and will lose their ability to survive solely under water and become truly terrestrial.
Note: This does not mean that marine hermit crabs are young land hermit crabs – they are a distinctly different group of hermit crabs who spend their entire lives in the sea, with only brief excursions onto the rocks of tidepools. These crabs will not survive if they are subjected to the living conditions that land hermit crabs thrive in.
Coenobita perlatus and Coenobita rugosus
I know there are many kinds of land hermit crabs currently unavailable in the US pet trade – unfortunately, I don’t have exhaustive information even on all of the species names, much less where each specific species is found in the wild.
Because of the limitations in my knowledge and the information that’s currently available to me, I’ve decided to concentrate on the land hermit crabs I do know about – the ones regularly available for purchase in the US.
C. clypeatus, or purple pinchers, are found in southern Florida and all through the Carribean and even as far south as the northern coast of South America.
C. rugosus, or ruggies, are found from the east African coast to the southwest Pacific.
C. compressus, or Ecuadorians, are found from the far southern coast of California to the Peruvian coast.
C. perlatus, or strawberries, are found from Tanzania to the southwest Pacific, as well as in Australia.
C. brevimanus, or indos, are found from the east African coastline to the southwest pacific.
C. cavipes, or cavs, can be found from east Africa to the western Pacific.