Early in the career of the dawn mammals, in the treetop abode of a superior pair of these agile creatures, twins were born, one male and one female. Compared with their ancestors, they were really handsome little creatures. They had little hair on their bodies, but this was no disability as they lived in a warm and equable climate.
These children grew to be a little over four feet in height. They were in every way larger than their parents, having longer legs and shorter arms. They had almost perfectly opposable thumbs, just about as well adapted for diversified work as the present human thumb. They walked upright, having feet almost as well suited for walking as those of the later human races.
Their brains were inferior to, and smaller than, those of human beings but very superior to, and comparatively much larger than, those of their ancestors. The twins early displayed superior intelligence and were soon recognized as the heads of the whole tribe of dawn mammals, really instituting a primitive form of social organization and a crude economic division of labor. This brother and sister mated and soon enjoyed the society of twenty-one children much like themselves, all more than four feet tall and in every way superior to the ancestral species. This new group formed the nucleus of the mid-mammals.
When the numbers of this new and superior group grew great, war, relentless war, broke out; and when the terrible struggle was over, not a single individual of the pre-existent and ancestral race of dawn mammals remained alive. The less numerous but more powerful and intelligent offshoot of the species had survived at the expense of their ancestors.
And now, for almost fifteen thousand years (six hundred generations), this creature became the terror of this part of the world. All of the great and vicious animals of former times had perished. The large beasts native to these regions were not carnivorous, and the larger species of the cat family, lions and tigers, had not yet invaded this peculiarly sheltered nook of the earth’s surface. Therefore did these mid-mammals wax valiant and subdue the whole of their corner of creation.
Compared with the ancestral species, the mid-mammals were an improvement in every way. Even their potential life span was longer, being about twenty-five years. A number of rudimentary human traits appeared in this new species. In addition to the innate propensities exhibited by their ancestors, these mid-mammals were capable of showing disgust in certain repulsive situations. They further possessed a well-defined hoarding instinct; they would hide food for subsequent use and were greatly given to the collection of smooth round pebbles and certain types of round stones suitable for defensive and offensive ammunition.
These mid-mammals were the first to exhibit a definite construction propensity, as shown in their rivalry in the building of both treetop homes and their many-tunneled subterranean retreats; they were the first species of mammals ever to provide for safety in both arboreal and underground shelters. They largely forsook the trees as places of abode, living on the ground during the day and sleeping in the treetops at night.
As time passed, the natural increase in numbers eventually resulted in serious food competition and sex rivalry, all of which culminated in a series of internecine battles that nearly destroyed the entire species. These struggles continued until only one group of less than one hundred individuals was left alive. But peace once more prevailed, and this lone surviving tribe built anew its treetop bedrooms and once again resumed a normal and semipeaceful existence.
You can hardly realize by what narrow margins your prehuman ancestors missed extinction from time to time. Had the ancestral frog of all humanity jumped two inches less on a certain occasion, the whole course of evolution would have been markedly changed. The immediate lemurlike mother of the dawn-mammal species escaped death no less than five times by mere hairbreadth margins before she gave birth to the father of the new and higher mammalian order. But the closest call of all was when lightning struck the tree in which the prospective mother of the Primates twins was sleeping. Both of these mid-mammal parents were severely shocked and badly burned; three of their seven children were killed by this bolt from the skies. These evolving animals were almost superstitious. This couple whose treetop home had been struck were really the leaders of the more progressive group of the mid-mammal species; and following their example, more than half the tribe, embracing the more intelligent families, moved about two miles away from this locality and began the construction of new treetop abodes and new ground shelters—their transient retreats in time of sudden danger.
Soon after the completion of their home, this couple, veterans of so many struggles, found themselves the proud parents of twins, the most interesting and important animals ever to have been born into the world up to that time, for they were the first of the new species of Primates constituting the next vital step in prehuman evolution.
Contemporaneously with the birth of these Primates twins, another couple—a peculiarly retarded male and female of the mid-mammal tribe, a couple that were both mentally and physically inferior—also gave birth to twins. These twins, one male and one female, were indifferent to conquest; they were concerned only with obtaining food and, since they would not eat flesh, soon lost all interest in seeking prey. These retarded twins became the founders of the modern simian tribes. Their descendants sought the warmer southern regions with their mild climates and an abundance of tropical fruits, where they have continued much as of that day except for those branches which mated with the earlier types of gibbons and apes and have greatly deteriorated in consequence.
And so it may be readily seen that man and the ape are related only in that they sprang from the mid-mammals, a tribe in which there occurred the contemporaneous birth and subsequent segregation of two pairs of twins: the inferior pair destined to produce the modern types of monkey, baboon, chimpanzee, and gorilla; the superior pair destined to continue the line of ascent which evolved into man himself.
Modern man and the simians did spring from the same tribe and species but not from the same parents. Man’s ancestors are descended from the superior strains of the selected remnant of this mid-mammal tribe, whereas the modern simians (excepting certain pre-existent types of lemurs, gibbons, apes, and other monkeylike creatures) are the descendants of the most inferior couple of this mid-mammal group, a couple who only survived by hiding themselves in a subterranean food-storage retreat for more than two weeks during the last fierce battle of their tribe, emerging only after the hostilities were well over.