That’s what Tufts Professor Sara M. Lewis told Scientific American about the Caribbean hermit crab, a crab whose real life social networking is along the lines of “Here, let me help you out of that.”
Professor Lewis and Tufts graduate school alumni Dr. Randi D. Rotjan, now an Associate Research Scientist at the New England Aquarium, captured some classic Caribbean crab behavior that’s never before been taped.
It’s called a synchronous vacancy chain, in which the hermit crabs gather at a shell that is too big for all of them. When a crab finally comes along that fits, they help him into his new home. The next largest crab present is then helped into the first crab’s vacated shell, and on down the line until everyone receives an upgrade.
The whole thing is explained here, definitely worth a looksey.