Widehand Hermit and Hermit Crab Sponge

Widehand Hermit and Sponge


Widehand Hermit and Hermit Crab Sponge
Elassochirus tenuimanus and Suberites sp.


Friday Harbor Marine Laboratories, University of Washington
San Juan Island, Washington

Archival Pigment Print

Most of us are so familiar with hermit crabs, which have been popularized as children’s pets and animated characters, that we take for granted a remarkable evolutionary adaptation: They appropriate the dead skeletons of other, unrelated animals for their own use. In fact, most are completely reliant on those foreign skeletons, whose original owners were snails. Hermit crabs seek refuge not just in shells, but also in worm tubes, nut shells, bottle caps, plastic dolls’ heads, and in this case a living sponge. The arrangement benefits both parties: the crab receives protection and the sponge gains mobility and perhaps some table scraps.