The vast quantities of humanmade trash unleashed upon the seas usually harm the denizens of the deep. But hermit crabs may be taking advantage of the pollution, new research suggests. The crabs are climbing up the mobile property ladder by way of broken bottlenecks, plastic containers, and other trash.
Hermit crabs typically reside in secondhand mollusk shells collected from dead or living gastropods. They obtain their mobile homes in bizarre swap meets with other unsatisfied hermit crab homeowners, dig them up from the sea floor, or even fix up ancient fossil shells. Still, suitable shells are often in short supply--and human activities have added to crab housing shortages by hurting some mollusk populations.
Crab in a bottle.
CREDIT: D. K. A. BARNES/BIOLOGIST
Ironically, however, human trash might help fill the gap, says ecophysiologist David K. A. Barnes of the British Antarctic Survey in Cambridge, U.K. The quantity of ocean-borne trash--mostly plastic--is rising, he notes, and some of the refuse has become prized real estate.
Hermit crabs all over the Pacific and Indian oceans, from heavily developed Asian coastlines to remote islands, are starting to make homes in plastics and glass, Barnes reports in the December issue of Biologist. "Suitably shaped persistent rubbish, like bottle tops, could yet become one of the most plentiful sources of housing," he predicts.
