Page:Popular Science Monthly Volume 77.djvu/602

596 pet, while coming from northern Africa, doubtless arose from Asiatic forebears in Pliocene or Pleistocene times. What the origin of the various strains of dogs was we know not, though the wild forms most nearly allied are living in Asia to-day, and the greyhound and mastiff almost surely were domesticated in Africa thousands of years ago. I believe that we may safely give to Asia the honor of the birthplace of most of the domesticated species in Pliocene or Pleistocene times.

Nor does it seem that this remarkable evolutional acceleration during Pliocene times in central Asia was confined to the mammals alone. The ostrich, the highest type of ratite birds, arose in central Asia. The jungle fowl, the highest of the gallinaceous birds and the ancestral stock of our most valued domestic fowls, arose in India and is still at home there. The peacock is exclusively Asiatic; the gray goose, the parent of our domestic geese, has its home in part at least in Asia; and the same may be said of the ancestors of the domestic doves; while the domestic duck may have originated there for aught we yet know. The guinea fowls only are exclusively African, and the turkey American.

Of the reptiles I will venture to say less. But is it not a significant fact that the highest specialization of the reptilian class appeared during Pliocene times in the gigantic extinct gavials of central Asia? Certainly the cobra is entitled to a high but unenviable distinction among the snakes. And Megalobatrachus, the largest of all recent amphibians, lives in Japan and China. Finally, of the domestic plants by far the majority come directly or indirectly from the Asiatic flora.

Have all these and doubtless many other facts of their kind no significance? Has man been an exception among so many branches of vertebrate evolution? The common inference has been that so many of our domesticated animals and plants come from India because man first reached civilization there, but the inference is, I believe, quite unjustifiable. Man was born and attained elemental civilization in Asia because there was the place of all others upon the earth where evolution in general of organic life reached its highest development in late Cenozoic times. No mammals and few other creatures have been domesticated by man in thousands of years, for the simple reason that he had eliminated all but the most advanced and most adaptable long before, and none were left to compete with them.

That man originated in the western continent is quite impossible. There is not a particle of evidence in support of such an hypothesis, for there is no evidence that either man or any of his ancestry ever inhabited the western continent till late in Pleistocene times. Indeed, so far as North America is concerned, there is much to justify the assertion that the Pliocene and Pleistocene were a period of evolutional depression here, of relative quiescence when the rhinoceroses, tapirs,