I propose to you that the wolf-man myth is an allegory (yeah, you like that one? Its my fifty cent word of the day) to teach us ignorant men-folk of the female condition.

So check it out: this (traditionally) male individually is finely attuned to the lunar cycle; their biology and body chemistry change drastically for a brief period of time every twenty-eight or so days (at least in the original lore when the transformation was involuntary and controlled by the phase of the moon rather then the will of the affected individual). I guess the specific application of this mythos would determine whether this transformation is meant to illicit a sense of fear or terror from the viewer or one of compassion, sorrow and awe.