Too many authorities have written as if early man made a free choice of routes through Alaska and Canada. Actually, the animals he hunted chose his route for him—doubtless many routes. Unless he had learned to spear and net fish, the first invader probably pursued a herd of mammoth or musk ox across the land-bridge or over the frozen ice of later winters. You in your armchair are likely to suggest that, once man was in Alaska, he turned south of his own free will and intelligence in order to avoid the cold. The first trouble with that line of thought is that man had gone north in Asia. The second is that primitive man had no conception of where south lay or of the possibility of greater comfort there. At this point, you will probably say that, though he had no ideas about the nature of the south, he had brains enough to follow the sun. Unfortunately this would have spun him round like a slow-motion teetotum; for he entered North America in the neighborhood of the Arctic Circle where the summer sun moves in a great low circle, and sinks out of sight when winter sets in.

If you want to understand early man, and guess with some accuracy at why he came to the New World and how he happened to drift southward and eastward until he filled it, you must think of him as a wanderer looking for food. Game lured him on at random, and vegetation lured both beast and man. Man might eat his way through caribou country, and come upon the bison of another area. As he killed and wandered, he might go south or he might go east. But the animal—and the man who ate berries and roots and wild grains as well as meat—would move as the climate moved. The world has known many changes of climate and shifts of rain belts. Some of these have been extreme—in the Great Ice Age, for example—and some have been less marked. But they have moved the forests and the grasslands, and animals and man have moved with the vegetation.

During the past 100,000 years, glacialists believe that there were three periods when the inland ice melted sufficiently to allow the southward passage of both animals and man. The first was more than 75,000 years ago in the Sangamon Interglacial period before the time when the last, or Wisconsin, glaciation had covered the plains of Canada (see pages [26] and [27]). During the Wisconsin, a corridor probably opened about 50,000 years ago along the eastern foothills of the Rockies, and another, perhaps a little later, down the plateau between the northern Rockies and the Coast Range. The third opportunity for man to penetrate from the north came around 11,000 years ago, when the final retreat of the ice sheets began in those same regions.[17] Perhaps the land-bridge was still usable up to 10,000 years ago, but certainly later migrants had to cross Bering Strait by water or winter ice.

Bering Strait and the great glaciers were not the only obstacles to the peopling of the Americas. The Isthmus of Panama must have presented quite a problem to the pioneers who were to fill Amazonia and the Andean Highlands and to reach Cape Horn. Today nobody sets off blithely by foot through the jungle that separates Costa Rica from Colombia. The beach is the best pathway at low tide; but it is an intermittent one. It is better to hope that the shifts of climate which were involved with the glaciers made Panama a drier country than it is today.

Of course it was not only early man and his prey that used the routes from Siberia across Bering Strait and through Alaska and Canada. The later migrants—ancestors of the Algonquins, the Athapascans, and others—undoubtedly came in the same way.

Problematical Roads to the New World

Other routes from other lands may have brought other migrants. These routes are not so fanciful as the paths from Atlantis and Mu, but they have had few advocates. M. R. Harrington has mentioned the possibility that Magdalenian man of Glacial or Postglacial Europe may have crossed from Europe to Canada by way of Iceland and Greenland and various ice- and land-bridges to father the Eskimo.[18] Ellsworth Huntington adds to the land-bridge over Bering Strait “wind-bridges” across the middle Atlantic.[19] Like Father de Acosta, he believes that storms may have blown occasional vessels to the New World. To suggest that unwilling mariners from the Mediterranean may thus have made oneway trips, he cites from Stansbury Hagar[20] striking resemblances between the zodiacs of Europeans and of the Mayas, Aztecs, and even Peruvians. Whether this matter of the zodiacs is fact or fancy, Huntington’s unwilling voyagers could not have come much earlier than the birth of Christ. More fantastic were the claims voiced some years ago that the men who left skulls of Australoid or Melanesian type in the caves of South America reached that continent by a southern route across an Antarctic bridge of land and ice. Of much more serious importance is the possibility that the long-voyaging Polynesians, having negotiated the 5,000 or 6,000 miles that lay between their home on the edge of Asia and the Marquesas or Easter Island, would have tried occasionally to continue their eastward course. If they had done so, they could scarcely have missed South America. But this was in our own era, not in the time of early man.

Ware Dogma!

GLACIERS AND ICE FIELDS AS BARRIERS TO EARLY MAN

These maps follow the outlines of the continent today, and so do not show the land-bridge from Alaska to Siberia that existed in varying extent throughout the entire Wisconsin period. The maps indicate tentatively how the great white ice fields may have appeared to different areas at different times, producing an effect of shifting from west to east and then back across the continent. Drawn in 1936, the first three maps probably show too little ice in arctic Canada and in the Gulf of St. Lawrence and Newfoundland region. (After Antevs; the first three in Gladwin, 1937, the fourth from data furnished by Antevs.)