It's wolfman because the character is the wolfman, and he is a man (how's that for explanatory redundancy? ). But I've seen movies where a Gypsy woman is the suspect and she is referred to as a werewolf. So any human who turns into a were-animal becomes were- plus the name of that animal. Weredog, werebear, werewhale . Attaching a gender to it, dogman or bearwoman, is simply a matter of convenience. Now excuse me while I go sharpen my fangs!