Three Cheers for the Pom Pom Crab!

The Hawaiian Pom Pom Crab (Lybia edmondsoni), otherwise known as the Boxer Crab which is really boring, is the cheerleader of the oceans. Those “pom poms” that it carries are actually sea anemones which grow on the crab’s claws. The Pom Pom Crab and Anemone have a mutualism based relationship, meaning both the crab and anemone benefit from the arrangement.The Pom Pom Crab uses the anemones as a defense mechanism, waving his claws in the air wildly if a predator approaches so that the sting from the anemone will drive the other creature away. The anemones, on the other hand (no pun intended!), benefit by having the leftovers of any food the crab eats.

However, the bonding with the anemones is not required, and crabs can survive without them (as in aquarium-type situations) or some have been observed using sponges and corals in place of the anemones.