Sand Bubbler Crabs at Cape Tribulation 4 – Small ball-shaped sand pellets produced by the feeding activities of the Sand Bubbler Crab (Scopimera sp.) on the beach at Cape Tribulation in Queensland, Australia. Radiating lines of sandy balls surround each crab burrow. In this picture the crabs have burrowed into sand ripples and the balls have tended to roll down and accumulate in the grooves between the ridges rather than radiate out from the burrows.
Jessica's Nature Blog 