The Turtle weed crab Caphyra rotundifrons inhabits clumps of the dark green seaweed called Turtle weed. By carefully running your fingers through a clump of this dark green algae you will feel small lumps in the weed. When teased out, these are found to be small green crabs, which are so docile they will not even nip or attempt to run off. It is usual to find just one pair living in each clump, as presumably they protect their weed patch from other pairs. They have hooks on the ends of their legs, which enable them to cling to the weed, and prevent them from being washed away as the tide sweeps in.