SKULL AND TOOTH MORPHOLOGY OF FINNISH AND JAPANESE RACCOON DOGS

The skull and tooth morphometrics of Finnish and Japanese raccoon dogs (Nyctereutes procyonoides ussuriensis and N, p, viverrinus, respectiv ely) were examined and com pared. The skulls of Finnish raccoon dogs w ere larger overall than those of Japanese raccoon dogs (tanukis) and w ere also larger relative to occipital condyle breadth, i.e. body size. Almost all measurements differed among samples in relation to skull s ize, indicating differences in skull shape. Mandible width and jaw hei ght were the best measurements for discriminating among populations; t he mandible is both absolutely and relatively more robust and the jaws more powerful among Finnish than among Japanese raccoon dogs. Japanes e raccoon dogs have a relatively longer rostrum and longer tooth rows than Finnish raccoon dogs. Although the absolute measurements of most teeth of Finnish raccoon dogs were larger than those of Japanese racco on dogs, the relative measurements of molars in particular were larger in Japan than in Finland, indicating a larger grinding surface among Japanese raccoon dogs. We suggest that viverrinus has adapted to a mil der climate and less carnivorous diet than ussuriensis. The Japanese r accoon dog is smaller and, due to its less carnivorous diet, its head has become decreased in size and the jaws less powerful; however, sinc e its diet consists largely of invertebrates and coarse plant material , its molars have increased relative to skull size.