Three Roads to the South—with One Detour
Once in Alaska, man—early or not so early—had a number of routes to choose from. If he was of maritime habits, and crossed by water, he would have tended to stick to his boats, and sail or paddle southward and southeastward down the coast and on through the inland passages of lower Alaska and Canada which protect boats from ocean storms. When Frank C. Hibben found a certain early kind of spear point in a curio shop in Ketchikan, Alaska, and on the far-away shore of Cook Inlet, he called attention to a route—whether overland or by sea—which hardly anyone had stressed except Hrdlička.[12] Hrdlička stressed it because he brought man over after the glaciers and in boats. But even in the Great Ice Age this route was not impossible for men without boats. Migrants who had crossed by a land-bridge might have turned south along the Pacific shore, climbing and crossing the ice barriers of the glacial rivers that still slide slowly down from the inland mountains. Philip S. Smith points out that “ice surfaces allow fully as easy travel by sled and on foot as do the ordinary land surfaces.”[13] But was there game, as well as fish, along the coast to lure the migrant on and to sustain him upon the journey?
Other men seem to have chosen to tramp and hunt eastward and northeastward from the strait. In this direction there were two main routes open to men and game. One route led up the narrow lowlands of the northwest coast to the mouth of the Mackenzie River and then south up its long valley. The other, and much more likely path for early man, was up the ice-free Yukon and its tributaries. These would have taken him eastward to the Mackenzie or southward through the plateau between the northern Rockies and the Coastal Range. Hrdlička thought the Yukon valley a most unpromising route because of the turbulent rivers and the noxious insects; but most students disagree with him and stress the abundance of fish and game. There can be no question that some parts of this route were used by early man—and extinct mammals, too. His ancient spear points have been found in the muck beds of Fairbanks mingled with the fossilized bones of elephant, bison, camel, horse, and an extinct jaguar once called the Alaskan lion.[14] Other early points have been discovered in western Canada in the area of the mountain plateau. In 1944 Frederick Johnson located fifteen camp sites in early soil levels along the route of the plateau corridor and found many varieties of artifacts. Among these were a few points, most of them fragmentary, the butts of which resembled those of an early type.[15] Following Johnson in 1945, Douglas Leechman found other sites and artifacts along this route in soils formed perhaps 9,000 years ago.[16]
The Yukon valley rivers could have taken early man to the Mackenzie and to the northern edge of the plateau; but during a large part of the Great Ice Age he still faced the gigantic fields of snow and ice that covered half of North America. Although ice journeys may not be so very difficult, and early man had learned to live in the chill of northern Siberia (the Eskimo of today proves that human existence is possible in a land of little sun and much cold), we cannot believe that he attempted to cross the icy wastes. A journey on foot across a thousand or two thousand miles of ice becomes a sheer impossibility if there is no provender to be found along the way. There was certainly no food for musk ox or mammoth, and therefore no food for man. Without game to hunt, he would not have felt the impulse to invade the ice fields.
MIGRATION ROUTES
The pathways available to early man, as mapped by Carl Sauer—to which have been added a problematical route by sea along the southern coast of Alaska and another down the corridor between the eastern Rockies in Canada and the coastal range. (After Sauer, 1944.)
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.