Do crabs get depressed?

I think it's possible that my little crabby pattie is depressed. Ever since Marie-Antoinette died, Pinchy is acting odd. He isn't as active and he keeps burrowing in his sand. He switches from corner to corner. I miss his wee beady eyes staring at me. I hardly get to see them anymore because he's so busy sulking. I am going to have to try to get the pet store tomorrow and get him a new roommate. Poor little crabby pie.