There has also been some suggestion that this may be a North American Porcupine, which is the second largest of all rodents. It has a small head, a large, chunky body with a high arching back and short legs. Its head and body are 25 to 40 inches long, with a long, thick, muscular tail growing as long as 8 inches. It weighs from 10 to 40 pounds. In the winter, they mainly eat conifer needles and tree bark. They do not hibernate but sleep a lot and stay close to their dens in winter. Anyway, IMO, it is most likely a North American porcupine unless someone can come up with more definitive evidence that it is not. On the other, if it is a porcupine, it is one of the largest examples I have seen.