Well hello, did somebody call? But seriously, we've had this discussion a few times...with no solid conclusions. Although some consider him to be a mole (I don't), I think he is just a bit species-less to be honest. Partly because usually the animal characters are referred to as "the Frog", "the Bear", "Piggy", "Bunny", etc (although not all), or make at least a few animal-specific jokes, I don't think he ever has. There was, however, a picture book one which stated that he lived underground and ate roots of plants that just grew through into his kitchen. Once he left his home and came to the theater, didn't remember how he got there, and stayed.