Have you ever stuffed a snack bar or a piece of candy in your pocket, planning to eat it later? If so, you and a young spider crab have something in common: like you, young spider crabs like to take snacks with them by stuffing algae, plant bits, and whatever else they can find into the crevices of their shells. Their treats serve a double purpose, too, in camouflaging them as they crawl along the ocean floor. With all those meals stuffed in their shells, they look like walking plants! Spider crabs seem to outgrow this habit when they reach a carapace (that’s the top part of their exoskeleton) length of about three inches, but adults often have a layer of algae on their shells which camouflages them just as well.
So where can you find these camo’d creatures? If you find yourself on the Atlantic coast of North America, the Gulf of Mexico, or in Nova Scotia, check out tidal pools and eel grass beds along the low-tide mark all the way down to 150 feet deep. There are more than 600 species in the spider crab’s family, but Libinia emarginata has an unusual characteristic that separates it from many others. Rather than walking sideways like most other crabs, the spider crab prefers to walk forwards. When you find a spider crab, or any of its 600 cousins, be careful – no matter the size of the crab, the pincher claw will hurt if the crab feels threatened and defends itself!
