Tasmanian Devil Circling

We watched this guy run in a circle with a radius of about 15 metres for about 20 minutes. He just kept going round and round. It wasn't like the cartoon with fast tight little circles, but a nice slow pace 'round and 'round in circles. We stopped back about three hours later and he was still running 'round and 'round in nice little circles. I would yell at him when he went by, but he would only stop for a second and turn around as if to say shut up, then he kept on running on a path that he had worn through and through all day long.