There were lots of hermit crabs scooting around in the tide pools. A pair of them got into a bit of a scrimmage; actually, one attacked the other, who fought back for a bit then scuttled away, with the larger one in pursuit. They were in shells of the same species, and the crabs too seemed to be of the same species—their “feet” were light-coloured. I wonder what the fight was about. Maybe they were just feeling crabby.