Because they are often hunted by octopus and other bottom-dwelling marine animals, the Box Crab is a master of disguise. This crustacean’s descriptive name comes from its tendency to bury itself in the mud while pulling its legs in underneath its body and folding its claws in front of it – thereby appearing box-shaped. Because of this defensive – some once said cowardly – posture, they are sometimes referred to as “shame-faced crabs.”
A heavily calcified carapace covered with sharp spines aids in its natural camouflage. When lying motionless and covered in silt, the animal is often indistinguishable from the ocean bottom. The crab’s claws are well-designed for its life in the mud. The right claw has a pronounced hook and crushing protrusions used to dig out the crab’s favorite food – auger snails – and smash open their shells. The left claw is used more surgically, to carefully remove bits of meat and feed it into the crab’s mouth. Like others of its species, the Box Crab is mostly nocturnal.
Box Crabs prefer rocky outcrops and soft, muddy ocean bottoms where there are plenty of places to hide and food is abundant. In Oregon, they are generally found at a depth of approximately 400 to 580 feet (121 to 165 meters.) They can be found all along the Pacific coast from Alaska to San Diego, California.