written by Ava
Hermit crabs are my favourite crustaceans. They are surprisingly cute and extremely versatile. However, when I think hermit crab, I think shell, so imagine my surprise when I found out a new species of Hermit crab had recently been discovered that wore coral instead.
What makes this so interesting is that free living (separate from a reef, living independently) coral is usually inhabited by worms which keep the coral from being buried. In turn, the coral provides shelter for the worms. This is commonly called walking coral. On a routine collection of walking coral samples from southern Japan, scientists were surprised to find a small crab in a coral sample. In the crab-coral situation, the crab takes the place of the worm, keeping the coral from being buried, and the coral the place of the hermit crab’s shell. Unfortunately, the sample had already been preserved so the crab was not alive. As a result, scientists went back looking for a live sample. When their search came to fruition, they discovered that the crab was pretty much screwed into its shell (corkscrew tail in a corkscrew shell), meaning it can’t leave its coral shell. The coral shell actually grows along with crab. Instead of hunting for a new shell once it grows an old shell, it takes up permanent residence in it’s coral home.
With coral reefs dying, I think it would be interesting to find out if this free living coral would have any specific advantages, or if it would be hardier in the ocean, but I couldn’t find any research on this. All in all, it is really interesting to know that there is still so much to be discovered, even about something as common as crabs.