hermit crab

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any of numerous crabs, especially of the genera Pagurus and Eupagurus, that protect their soft uncovered abdomen by occupying the castoff shell of a univalve mollusk.
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Origin of hermit crab

First recorded in 1725–35
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023


Where does the word hermit crab come from?

It seems there comes a time in most every family’s life when you come home with a hermit crab, admittedly one of the least demanding pets you can have.

The term hermit crab dates back to at least 1725–35. Hermit refers to the method that the crab protects itself in which it uses castoff shells. Generally speaking , a hermit is a recluse. In zoology, a hermit can refer to any animal with solitary habits.

As for the word hermit itself? It ultimately comes from a Greek word meaning “living in a desert,” based on the language’s noun for “desert, desolation, solitude.” The word originally referred to religious people who lived solitary lives—like off alone in the desert—in the English language.

The word crab—like most of the words we’ve seen here—is found in Old English and has many Germanic cognates, like the dutch krab.

Now that you know how the hermit crab got its name, why not find out how some of our other most beloved pets got theirs in the slideshow: “Where Do The Words For Our Pets Come From?”

Did you know … ?

There are over 800 species of hermit crabs, and almost all of them live their whole lives in the ocean. Despite their name, hermit crabs are more closely related to species of lobsters than true crabs. Unlike true crabs, hermit crabs don’t have a hard exoskeleton that covers their whole body and have an exposed soft tail. Because they are unable to grow a shell of their own, hermit crabs find a discarded shell of another creature to protect their vulnerable tails.   

Despite their name, hermit crabs often live in large social groups, and after finding a new shell, will sometimes “gift” their old one to another hermit crab. Naming these crabs after hermits, then, is quite the misnomer.

How to use hermit crab in a sentence

British Dictionary definitions for hermit crab

hermit crab

any small soft-bodied decapod crustacean of the genus Pagurus and related genera, living in and carrying about the empty shells of whelks or similar molluscs
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012