Hohonu Moana: Exploring Deep Waters off Hawaiʻi






Creature Feature: Deepwater Hermit Crab

A deepwater hermit crab using an anemone as a shell was spotted during Dive 08.

A deepwater hermit crab using an anemone as a shell was spotted during Leg 4, Dive 08. Image courtesy of the NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana. Download larger version (1.3 Mb).

Watch video of a deepwater hermit crab and anemone from August 9, 2015.

September 22, 2015

Mary K. Wicksten
Texas A&M University

Hermit crabs are unusual in having a soft posterior region, the abdomen, hidden within a snail shell or other covering. A hermit crab must change shells throughout its life as it grows: that is, unless it is a deepwater hermit crab, family Parapaguridae.

Members of this family have a very strange association with a sea anemone, family Hormathiidae. The crab starts out inhabiting a shell. The sea anemone settles on the shell and then overgrows it, eventually dissolving the shell and forming a covering that expands as the crab grows.

This arrangement is useful for both the crab and the anemone. Experiments on shallow-water crabs indicate that the stinging tentacles of the anemone repel octopods. The anemone, in turn, gets free transportation.

 

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