Man is the only mammal whose normal method of locomotion is to walk on two legs. A pattern of mammal behavior that emerges only once in the whole history of life on earth takes a great deal of explaining.
![Man is the only mammal whose normal method of locomotion is to walk on two legs. A pattern of mammal behavior that emerges only once in the whole history of life on earth takes a great deal of explaining.](http://cdn.myquotes.org/images/elaine-morgan/man-is-the-only-mammal-whose-normal-method-of-locomotion-is-to-walk-on-two-legs-a-pattern-of-mammal.jpg)
Man is the only mammal whose normal method of locomotion is to walk on two legs. A pattern of mammal behavior that emerges only once in the whole history of life on earth takes a great deal of explaining.