Graceful Decorator Crab (Oregonia gracilis)
Graceful decorator crabs are the most common species of decorator crab in British Columbia. They are found from northern Alaska to central California and in Japan. They are frequently found in the intertidal zone, but can be found as deep as 436 m. Graceful decorator crabs have a brown heart shaped carapace that can grow to 5 cm across and five long walking legs. They have two long thin horns on their rostrum (a projection of the carapace between the eyes) and one spine behind their eyes. Their legs and claws are covered in short setae and the carapace is covered in hooked setae. Check out our crab video bellow for more information about identifying grateful decorator crabs.
Graceful decorator crabs get their name from employing a unique camouflage tactic, using the hooked setae on its carapace to attach other organisms to itself. They are often covered with algae, sponges, bryozoans, and hydroids. Their front legs have delicate slender claws specially adapted for the task of collecting organisms and transplanting them onto their carapace. When placed into a new environment graceful decorator crabs have been known to completely redecorate to match their new surroundings.
Graceful decorator crabs feed primarily on plankton, but they are far from picky eaters and will also scavenge carrion. Their creative colourful camouflage helps them blend in to their surroundings and effectively hide from predators. Their most prevalent predator is the Pacific halibut, but they are often targeted by sea otters and octopus as well.
To learn more check out our Seaquaria video about Decorator Crabs. Decorator Crabs are a common resident in our summer touch tanks!
For more information visit Central Coast Biodiversity and The Marine Detective