Hermit Crabs Socialize to Evict Their Neighbors

ScienceDaily (Oct. 26, 2012) — Social animals usually congregate for protection or mating or to capture bigger prey, but a University of California, Berkeley, biologist has found that the terrestrial hermit crab has a more self-serving social agenda: to kick another crab out of its shell and move into a larger home.

All hermit crabs appropriate abandoned snail shells for their homes, but the dozen or so species of land-based hermit crabs -- popular terrarium pets -- are the only ones that hollow out and remodel their shells, sometimes doubling the internal volume. This provides more room to grow, more room for eggs -- sometimes a thousand more eggs -- and a lighter home to lug around as they forage.

But empty snail shells are rare on land, so the best hope of moving to a new home is to kick others out of their remodeled shells, said Mark Laidre, a UC Berkeley Miller Post-Doctoral Fellow who reported this unusual behavior in this month's issue of the journal Current Biology.

Continued:  http://www.sciencedaily.com/releases/2012/10/121026125131.htm