This is interesting; but I can't help feeling that limiting comparison mostly to primates has potential to mislead his conclusion. I started from Wikipedia [1]

This is interesting; but I can't help feeling that limiting comparison mostly to primates has potential to mislead his conclusion. I started from Wikipedia [1] and worked outward with the reference material and the implication is that masturbation to completion is actually quite common. 1. http://en.wikipedia.org/wiki/Animal_sexual_behaviour#Autoeroticism_.28masturbation.29 http://en.wikipedia.org/wiki/Animal_sexual_behaviour#Autoero...