Many scientists believe that the Yetis observed across the world are giant apes as the Orang-Utans or Gorillas. The relationship between the Yeti and Homo sapiens has not been proven to be any closer than that between our species and the other great apes, except in shared posture and means of locomotion.

With the exception of his upright posture and loss of hair, man's differences from other primates are mainly in his brain, and those differences obviously result from a radical departure, a very long time ago, from the normal primate lifestyles. While all other species have relied on physical abilities and on instincts to hold a place in a competitive world, man has shifted his reliance to his brain.

In the case of ape-man (Yeti, Bigfoot, …) vs. ape, we appear to be dealing with a locomotor contrast like that which separated the first australopithecine from the ancestral African ape.

Disregarding whatever future evolution might occur, this initial "step" need not be ranked as anything more than a species worth of distinction at that time.

In short, if upright posture is what makes an animal a human, then the reports describe a human, but if it is his brain that distinguishes Home sapiens from his animal relatives, then the Sasquatch is an animal, an upright ape and nothing more.