Physical Description

  • They have a teardrop-shaped body with a spiny, bumpy shell.
  • Have spine-like points on their downward-facing snout.
  • Eight long, spindly legs with big, knobby joints, and two claws.
  • Adult males reach a diameter of 6.5 inches and have larger claws; adult females reach a diameter of 4.5 inches.
  • Juveniles cover themselves with barnacles, bryozoans, hydroids, and algae for camouflage.
  • Adults develop a film of fuzzy green algae all over their bodies.


  • Point Reyes, California to Baja California, Mexico.


  • Found at depths of 20-500 feet.
  • Live on rocky reefs and pilings.


  • Females are sexually mature when 4-7 inches wide, males at 4-9.5 inches wide.
  • Males and females pile up on shore to mate.
  • They hook back to back to mate.
  • Mating occurs in late spring-summer.
  • Females can store sperm when there’s an absence of males.
  • Each brood includes 125,000-500,000 eggs.


  • Scavengers, they eat living and dead things on the seafloor.
  • Known to eat octopus, starfish, and clams.


  • Cabezon, California sheephead, octopus, sharks, and rays.

Interesting Facts

  • The name sheep crab may come from the fuzzy layer of algae adults grow on their shells. 
  • They live to be about four years old.
  • They are the largest species of California spider crabs.

Sources: California Sea Grant; Monterey Bay Aquarium

Photo: Herb Gruenhagen