Caribbean Hermit Crab

Looks how to spot one

Hard exoskeleton, soft coiled abdomen protected by a borrowed snail shell

A ten-legged land crustacean that tucks its soft, curled rear body into an empty sea-snail shell and carries it everywhere. Its left claw is noticeably bigger than the right and is coloured purple; that big claw doubles as a door that can seal the shell entrance. Instead of breathing underwater it uses specially adapted gills that work in air, kept moist by water held inside the shell.12

Personality what they are like

A curious, mostly night-active crab that likes company of its own kind. It spends a lot of time digging and exploring, and may pull back into its shell when unsure. Crabs sometimes squabble over shells, and they can make a soft chirping sound.41

Daily activity how busy a day looks

Most active at night. Needs deep substrate to dig and burrow in, plus things to climb and explore; spare shells give it something to investigate and move into as it grows.41

Grooming and care the hands-on bits

Check temperature and humidity daily with a thermometer and hygrometer. Offer at least three to five clean empty shells of assorted sizes per crab so it can move up a size. It sheds its exoskeleton about once or twice a year, often while buried, and the process can take days to weeks, so leave it undisturbed while it moults.4

Home where they are happiest

PetMD suggests a 10-gallon (about 38 L) glass tank for one or two crabs, adding about 5 gallons (19 L) for each extra crab. Keep the warm side near 27 C (80 F) and the cool side or night-time near 21 C (70 F), with humidity of 70-90%. Use a sand and coconut-fibre mix (about 5:1) at least three times as deep as the largest crab is tall. Provide two shallow water dishes: dechlorinated fresh water and salt water (specific gravity 1.021-1.026). In the wild adults shelter under tree roots and can live well inland.41

Food basics what goes in the bowl

An omnivore and scavenger. Wild crabs eat plant matter, overripe fruit and animal remains. In captivity feed once a day with a commercial hermit crab food plus occasional fruit, vegetables, nuts and brine shrimp, with a calcium supplement.14

Company who they like around

A social species that does best kept in pairs or groups rather than alone. Wild crabs gather in groups and even line up by size to trade shells with one another.46

The story where it all began

Fabricius formally described the species in 1787, and it is the only land hermit crab native to the Atlantic coast of the Americas, ranging from southern Florida through the Caribbean islands to Belize and Venezuela. Local people across the region know it by many names, among them soldier crab and tree crab, and the purple claw earned it the nickname purple pincher. Adults live on land, sometimes far from the beach, but every year they return to the shoreline to release their eggs into the sea; on Mona Island off Puerto Rico these mass trips peak around August and are known in English-speaking parts of the Caribbean as the 'washing'. The tiny larvae drift in the plankton, then settle, find a small snail shell and move onto land. Its hardiness and long life made it one of the two land hermit crabs most commonly sold as pets in the United States, alongside the Ecuadorian hermit crab.127

Recognised by the official bits

Zootaxa annotated checklist of anomuran crabs (McLaughlin et al., 2010), as cited by Wikipedia

Accepted species Coenobita clypeatus (Fabricius, 1787), one of the living species of the land hermit crab genus Coenobita (family Coenobitidae).2

IUCN (via SeaLifeBase)

Not Evaluated.3