A group of crabs is called a cast.
Crabs are found scuttling along nearly every coastline on Earth, and while they’re not exactly famous for organized group behavior, the sight of several crabs sideways-walking across a beach or tide pool at once is common enough that it earned its own collective noun. Whether “cast” is describing a true social gathering or just a bunch of crabs that happen to be in the same spot depends a lot on the species.
What Is a Group of Crabs Called?
The most widely used term is a cast of crabs. You’ll also occasionally see a consortium of crabs, a more formal-sounding alternative that leans into the idea of an organized, cooperative assembly rather than a chance gathering. Both terms show up in collective-noun references, with “cast” being the more common of the two.
Where Did the Name Come From?
Most classic animal collective nouns trace back to the “terms of venery” tradition cataloged in the Book of Saint Albans (1486), a list built around medieval hunting and falconry. Crabs weren’t hunted quarry in that tradition, so “cast” almost certainly isn’t part of that lineage. It reads more like a borrowed theatrical term, the same kind of word used for the “cast” of a play, applied to crabs because a cluster of them moving and clacking together can look a bit like a company of characters assembled on a stage.
“Consortium” has an even more modern flavor. It’s a word usually reserved for a formal association of businesses or organizations working toward a shared purpose, and its application to crabs seems to be a playful, descriptive stretch rather than anything with a documented historical origin.
In short: neither term for crabs appears to trace back to an old, verifiable source. Both look like later additions to the collective-noun tradition, chosen because they sounded fitting rather than because of any recorded etymology specific to crabs.
Crab Facts
- Habitat: Crabs live in nearly every environment connected to water, from coral reefs and rocky shorelines to the deep sea, estuaries, freshwater streams, and even on land in warm, humid regions.
- Social behavior: Most crab species are solitary and territorial rather than social. “Cast” is more of a borrowed, whimsical word than a biologically descriptive one, though some species do gather in large numbers for molting, mating, or migration, the mass migration of Christmas Island red crabs to the sea each year being one of the most dramatic examples.
- Diet: Crabs are mostly omnivorous scavengers, eating algae, mollusks, worms, plankton, and whatever dead organic material they come across.
- Lifespan: Lifespan varies widely by species, from around 3-4 years for smaller species like blue crabs up to 8-13 years or more for larger species like Dungeness crabs; the slow-growing coconut crab can live well past 40 years.
- Sideways specialists: Crabs walk sideways because their leg joints bend more efficiently in that direction, making it faster and more stable than moving forward.
Example Sentences
- A cast of crabs scattered under the rocks as the tide pulled back.
- Marine biologists photographed a consortium of crabs clustered around the wreck.
Other Names for a Group of Crabs
Explore the individual collective nouns for crabs in more depth:
Frequently Asked Questions
What is a group of crabs called?
A group of crabs is most commonly called a cast. Consortium is a less common alternate term.
Is “cast” the same word used for a play?
Yes, it appears to be the same borrowed theatrical term, applied to crabs because a cluster of them can resemble a company of characters assembled together.
What does “consortium” mean when applied to crabs?
Consortium normally describes a formal association of organizations working toward a shared purpose. Applied to crabs, it’s a descriptive stretch rather than a documented historical term.
Do crabs actually gather in groups?
Most crab species are solitary and territorial day to day, but some species gather in large numbers for molting, mating, or migration, such as the annual mass migration of Christmas Island red crabs.
How long do crabs live?
It varies by species. Smaller crabs like blue crabs typically live 3-4 years, larger species like Dungeness crabs can live 8-13 years, and slow-growing coconut crabs can live past 40 years.
Related: Collective Nouns for Crustaceans