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Hermit Crabs

Unauna

Hermit crabs are one of the most common types of tide pool animals. Characterized by its soft abdomen or tail, hermit crabs rely on empty snail shells as a means of protection. They can fully withdraw themselves into the shell, sometimes using an oversize claw as a seal. Hermit crabs will occupy any size shell and as the animal grows larger it seeks a larger more accommodating home. If there is a shortage of snail shells, other hollow objects will frequently be used as temporary homes.

Like other species of decapods, hermit crabs have five pairs of legs but only the second and third pairs are typically used for walking. The first pair bears claws and the last two pairs are used to grip the shell. When switching to a new shell, the hermit crabs pull out their tail and back into a new shell in a blink of an eye. A hermit crab might test a shell several times before it becomes its permanent home, at least until he outgrows that one and the search begins for a new shell.

Most species of hermit crabs will scavenge the reefs consuming fish and other invertebrates. Many will also eat algae. Many display beautiful coloration and elaborate eye colors. Most shallow water species are small and timid and can safely be picked up even by children.

*Due to the constant rotation of animals back to the ocean, the presence of any specific animal cannot be guaranteed.

Did You Know...
Roughly 23 species of marine hermit crabs inhabit Hawaiian shorelines.
Hawaiian Name:
Unauna
Scientific Name:
Family Diogenidae and Paguridae
Where to See:
Living Reef*
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