Species Feature: Decorator crabs

Nothing beats crazy decorator crabs

The first time I saw a crab with decorations was years ago in the Maldives while on a fast-paced night dive with strong currents and lots of massive rays and sharks flying by.  Yet what caught my attention were not the stunning nurse and reef sharks but a crab with anemones that wandered out from under the rock we were clinging to.  I wasn’t able to get a photo so insisted on sketching it once back on the boat because I thought it was the most awesome critter ever!  Come to find out is was an anemone hermit crab and they attach anemones to their shells for protection, moving their anemones from one shell to the next if they change homes.  Often the hermit crabs have three or four anemones but on occasion you find what I call the super ambitious hermit crab who attaches over ten anemones to its shell.  All I can say is if I were a female hermit crab I would reward that enterprising male hermit crab!  I’ve since seen anemone hermit crabs in the UK, Greece, Philippines, Costa Rica, and Indonesia.  They hold a special place in my heart and I still photograph even the most average ones.

As I started diving more, especially in the Indo-Pacific, I discovered there are loads more crabs who attach all kinds of decorations on themselves for camouflage and protection such as sponge, weeds, soft corals, hydroids, and anemones.  My partner and I often have discussions about how they choose what to put on themselves, like it is a fashion statement.  Is it just genetically programmed into them to find sponge and attach it to the little hooks on their bodies which hold it?  Sometimes they’ll even carry huge chunks of coral so you spot them as a coral block runs past!  Here is a selection of my favorite decorator crabs: