Cabrillo Marine Aquarium

Masking Crab

Loxorhynchus crispatus


Fun Facts

    The masking crab decorates itself with bits of algae, sponges and bryozoans.

    The “decorating” behavior is used for camouflage and is also called “masking”.



  The masking crab is a type of spider crab that lives in the low to subtidal zone of the rocky intertidal, on subtidal pilings, and in kelp holdfasts. Masking crabs occur from Humboldt County, California to Isla Natividad, Baja California. The carapace (or body) is somewhat triangular and is covered with tubercles (bumps).

Masking crabs feed on a wide range of invertebrates, such as sponges, other crustaceans, and bryozoans. These crabs are usually found so densely covered or “decorated” with other invertebrates, that at times they are barely recognized as crabs. They use hooks and barbs (called setae) on their back to attach other invertebrates. Adult males stop decorating at sexual maturity, but by then they are so large that they have few predators.

Masking crabs are usually found at the Aquarium in tank number 9 and 14.