Discovering that the correct term for a grouping of a crabs is, yes… wait for it… a cast of crabs.

This essentialia comes to us by way of a recent post on DailyKos re the effect of global warming on the terrestrial and marine environment of Greenland. The author mentioned that things like squid, sharks, and of course crabs are now seen in ever-increasing numbers off the coast of Greenland. Since that coast itself is growing, courtesy of peninsulas becoming islands, you can picture quite a frolicsome affair there.

Curiously, after a burst of lamentation and rending of hair re the warming planet, almost all of the comments to the post are about the correct term for a group of crabs (with a diversion into crab biology after somebody made an offhand mention of “crab family life”). The cream of the suggestion crop: an itch, a crock, a crib, and a very competitive entry: “a republican of crabs”.
Other excellent group names:

• a murder of crows
• a jar of nuthatches
• a romp of otters
• a richness of martens
• a tower of giraffes
• an unkindness of ravens

Find more at Dictionary.com, Wikipedia of course (here and here), and our friends at USGS.