In marine ecosystems, certain ‘walking’ corals act in partnership with marine worms known as sipunculans. The worm shelters in the coral’s cavity and receives protection from predators, in return providing transportation and preventing the coral being buried in sea floor sediment. These two organisms have evolved a specialized codependence, and in such relationships, it is usually impossible to replace either partner with a different species.
Hermit crabs are best known for scavenging seashells left by marine creatures such as snails to protect their soft abdomens. However, when the authors of the present study surveyed walking corals in the Amami Islands of southern Japan, they identified a new species of hermit crab that adopts the walking coral as its home instead of a seashell.
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