Komamura is an anthropomorphic wolf. When Yachiru called him doggy, he corrected her, saying that he is a wolf. This is the only time Komamura himself comments on it. It is in Bleach Official Bootleg KaraBuri+ (one of the databooks). In the final arc, it is revealed that Sajin isn't just any kind of wolf, but in fact a member of a race of wolfmen.