A sea anemone found off Japan does not just live on a species of crab, but actually grows its host’s shell like a home extension

Deep in the Kumano Sea off the south-eastern coast of Japan, hermit crabs crawl around sporting what look like pearly pink flowers on their shells. But these are not floral arrangements – they are members of a newly discovered species of sea anemone, Stylobates calcifer, which live on the hermit crabs’ shells.

This kind of sea anemone and hermit crab cohabitation is not unique: dozens of anemone species live exclusively with hermit crabs. It’s a win-win situation – the anemones’ petal-like stinging tentacles protect the crabs from predators, while they hitch rides to new feeding grounds and get leftover scraps of the crab’s food.