Going back to the birth of the superior twins, one male and one female, to the two leading members of the mid-mammal tribe: These animal babies were of an unusual order; they had still less hair on their bodies than their parents and, when very young, insisted on walking upright. Their ancestors had always learned to walk on their hind legs, but these Primates twins stood erect from the beginning. They attained a height of over five feet, and their heads grew larger in comparison with others among the tribe. While early learning to communicate with each other by means of signs and sounds, they were never able to make their people understand these new symbols.
When about fourteen years of age, they fled from the tribe, going west to raise their family and establish the new species of Primates. And these new creatures are very properly denominated Primates since they were the direct and immediate animal ancestors of the human family itself.
Thus it was that the Primates came to occupy a region on the west coast of the Mesopotamian peninsula as it then projected into the southern sea, while the less intelligent and closely related tribes lived around the peninsula point and up the eastern shore line.
The Primates were more human and less animal than their mid-mammal predecessors. The skeletal proportions of this new species were very similar to those of the primitive human races. The human type of hand and foot had fully developed, and these creatures could walk and even run as well as any of their later-day human descendants. They largely abandoned tree life, though continuing to resort to the treetops as a safety measure at night, for like their earlier ancestors, they were greatly subject to fear. The increased use of their hands did much to develop inherent brain power, but they did not yet possess minds that could really be called human.
Although in emotional nature the Primates differed little from their forebears, they exhibited more of a human trend in all of their propensities. They were, indeed, splendid and superior animals, reaching maturity at about ten years of age and having a natural life span of about forty years. That is, they might have lived that long had they died natural deaths, but in those early days very few animals ever died a natural death; the struggle for existence was altogether too intense.
And now, after almost nine hundred generations of development, covering about twenty-one thousand years from the origin of the dawn mammals, the Primates suddenly gave birth to two remarkable creatures, the first true human beings.
Thus it was that the dawn mammals, springing from the North American lemur type, gave origin to the mid-mammals, and these mid-mammals in turn produced the superior Primates, who became the immediate ancestors of the primitive human race. The Primates tribes were the last vital link in the evolution of man, but in less than five thousand years not a single individual of these extraordinary tribes was left.