Awesome Animal Fact - Thieving Pea Crab

Did you know the tiny pea crab spends its entire life inside a clam or oyster shell? The pea crab (Pinnotheres pisum), which is about the size of a pea, is considered a kleptoparasite because it steals food and oxygen from its host. As the oyster or clam filters food from the water, the pea crab steals a portion of the food. The crab also gets a safe home to live in.

Pea crabs often choose an oyster or clam as a host, but sometimes they live inside a sand dollar, in the tube of a parchment worm, or in the rectum of a sea cucumber. Sure, a sea cucumber's rectum doesn't sound like a desirable apartment, but the rent is affordable.

Interestingly, male pea crabs remain free-swimming their entire lives. It is the females that are kleptoparasites.

If you are eating seafood and find a pea crab inside one of your oysters, don't be grossed out. Pea crabs are considered a delicacy. Not only that, finding a pea crab in your oyster is considered good luck!

Photo Credits:
- Pea crab - Kikkiwikiwaki, CC BY 3.0, via Wikimedia Commons