This does not impair the value of the general picture which we can make in our minds. It is not essentially different from what is the case in history. If we speak of the Græco-Roman world from the days of Aristides to those of Marcus Aurelius, we outline a historical period which has a real unity, and of which all the parts are bound together by real ties and real resemblances. Nevertheless, there were sharp differences in the successive cultures of this period; even the two centuries which intervened, say, between Miltiades and Demetrius Poliorketes, or between Marius and Trajan, showed such differences. Dealing roughly with the period as a whole, it would not be necessary to try to draw all the distinctions and make all the qualifications that would be essential to minutely accurate treatment; such treatment would merely mar the outlines of a general sketch. The same thing is, of course, true of an outline sketch of what our present knowledge shows of man's most wide-spread beast associates, when he had begun, in forms not very different from those of the lower savages to-day, to spread over the world's surface.
Therefore it is necessary to remember that in dealing even with such a recent chapter of paleontological discovery as that concerned with early man and the great four-footed creatures that were his contemporaries, our general picture can rarely pretend to more than general accuracy. It is only in prehistoric and protohistoric Europe that the early career of "homo sapiens" and his immediate predecessors has been worked out in sufficient detail to give even the roughest idea of its successive stages, and of the varying groups of great beasts with which at the different stages man was associated. This is because the record has been better preserved, and more closely studied in Europe than elsewhere; for it seems fairly certain that it is in Eurasia, in the palæarctic realm, that there took place the development of the more or less ape-like predecessors of man and then of man himself. It is in Eurasia that all of the remains of man's immediate predecessors have been found—from the Javan pithecanthropus which can only doubtfully be called human, to the Piltdown and Heidelberg men, who were undoubtedly human, but who were so much closer than any existing savage to the beasts that (unless our present imperfect knowledge proves erroneous) they can hardly be deemed specifically identical with modern homo sapiens. Even the more modern Neanderthal men are probably not ancestral to our own stock. It is in Europe, following on these predecessors of existing man, that we find the skeletons, the weapons and tools, and the carvings of existing man in his earliest stages; and mingled with his remains those of the strange and mighty beasts which dwelt beside him in the land. Probably these European forefathers of existing man came from a stock which had previously gone through its early human and prehuman stages in Asia. But we only know what happened in Europe. There was a slow, halting, and interrupted but on the whole steady development in physical type—sometimes the type itself gradually changing, while sometimes it was displaced by a wholly different type of wholly different blood. Roughly parallel with this was a corresponding development in cultural type. Probably from the earliest times, and certainly in late times, development or change in physical type was often wholly unrelated to development or change in culture. Sometimes the cultural change was an autochthonous development. Sometimes it was due to a more or less complete change in blood, owing to the immigration of a strong alien type of humanity. Sometimes it was due to the adoption of an alien culture.
Many good observers nowadays, judging from the facts at present accessible, are inclined to think that the American Indian stocks were the first human stocks that peopled the western hemisphere, that they are by blood nearest of kin to certain race-elements still existing in northeastern Asia—representing the only inhabitants of northeastern Asia when man first penetrated from there to northwestern America—and that more remotely they may be kin to certain late Palæolithic men of Europe. But much of the American Indian culture was essentially a Neolithic culture, seemingly from the beginning. In places—Peru, Maya-land, the Mexican plateau—it at times developed into a civilization equally extraordinary for its achievements and for its shortcomings and evanescence; but it never developed a metal epoch corresponding to, say, the bronze age of the Mediterranean, and although the small camel, the llama, was tamed in South America, in North America, the ox, sheep, white goat, and reindeer were never made servants of man, as befell so many corresponding beasts of Eurasia.
In this last respect the American Indians stayed almost on the level of the African tribes, whose native civilization was otherwise far less advanced. The African buffalo is as readily tamed as its Asiatic brother; the zebra was as susceptible of taming as the early wild horse and ass; the eland is probably of all big ruminants the one that most readily lends itself to domestication. But none of them was tamed until tribes owning animals which had been tamed for ages appeared in Africa; and then the already-tamed animals were accepted in their stead. The asses, cattle, sheep, and goats of Asia are now the domestic animals of the negroes and of the whites in Africa, merely because it is easier, more profitable, and more convenient to deal with animals already accustomed for ages to the yoke of domestic servitude than to again go through the labor incident to changing a wild into a tame beast.
It is probable that during the immense stretch of time which in Europe covered the growth of the various successive Palæolithic, and finally Neolithic, cultures—the "old-stone" ages during which man used stone implements which he merely chipped and flaked, and the "new-stone" age in which he ground and polished them—there happened time and again what has happened in the history and prehistory of man in Africa and North America. One of the incidents in this parallelism is the way in which the inhabitants accepted animals already trained and brought from elsewhere rather than attempt to train the similar beasts of their own forests. Doubtless the reason why the European bison is not a domestic animal is exactly the same as the reason why the American bison and African buffalo are not domestic animals. The northern European hunting savages were displaced or subjugated by, or received a higher culture from, tribes bringing from Asia or from the Mediterranean lands the cattle they had already tamed. The same things happened, in Africa south of the Sahara while it was still shrouded from civilized vision, and in America since the coming of the European.
These hunting savages existed for ages, for hundreds of thousands of years, in Europe. During this period of time—immense by historic standards, yet geologically a mere moment—many different human types succeeded one another. The climate swung to and from glacial to subtropical; fauna succeeded fauna. One group of species of big beasts succeeded another as the climate and plant life changed; and then itself gave place to a third; and perhaps once more resumed its ancient place as the physical conditions again became what they once had been. At certain periods the musk-ox, the reindeer, the woolly rhinoceros, and the hairy mammoth, together with huge cave-bears, were found; at other periods southern forms of elephant and rhinoceros, and such tropical creatures as the hippopotamus, replaced the beasts of the snow land. Horses of different species were sometimes present in incredible numbers. There were species of wild cattle, including the European bison, and the urus or aurochs—spoken of by Cæsar, and kin to, and doubtless partly ancestral to, the tame ox. The cave-lion, perhaps indistinguishable from the modern African lion, was the most formidable beast of prey. I say "perhaps" indistinguishable, for we cannot be quite certain. Some of the races of cave-dwelling men were good artists, and carved spirited figures of mammoth, rhinoceros, bison, horse, reindeer, and bear on ivory, or on the walls of caves. The big lion-like cats appear only rarely in these pictures.
In most cases the arctic and warm-temperate or near-tropical animals supplanted one another only incompletely as the waves of life advanced and receded when the climate changed. This seems a rather puzzling conjunction. The explanation is twofold. When the climate changes, when it becomes warmer, for instance, northern creatures that once were at home in the lowlands draw off into the neighboring highlands, leaving their old haunts to newcomers from the south, while nevertheless the two faunas may be only a few miles apart; just as in Montana and Alberta moose and caribou in certain places were found side by side with the prongbuck. Moreover, some species possess an adaptability which their close kin do not, and can thrive under widely different temperature conditions. A century ago the hippopotamus was found in the temperate Cape Colony, close to mountain ranges climatically fit for the typical beasts of north-temperate Eurasia. In Arizona at the present day mammals and birds of the Canadian fauna live on the mountain tops around the bases of which flourish animals characteristic of the tropical Mexican plateau; the former having been left stranded on high mountain islands when, with the retreat of the glaciers, the climate of the United States grew warmer and the tide of southern life-forms swept northward over the lowlands. Under such conditions the same river deposits might show a combination of utterly different faunas. Moreover, some modern animals are found from the arctics to the tropics. The American lynx extends, in closely connected forms, from the torrid deserts of Mexico to arctic Alaska; so does the mountain-sheep. The tiger flourishes in the steaming Malay forests and in snowy Manchuria. I have found the cougar breeding in the frozen, bitter midwinter among the high Rockies, in a country where snow covered the ground for six months, and where the caribou would be entirely at home; and again in Brazil under the equator, in the atmosphere of a hot-house. There were periods, during the ages before history dawned, but when man had long dwelt in Europe, in which herds of reindeer may have roamed the French and English uplands within sight of rivers wherein the hippopotamus dwelt as comfortably as he recently did at the Cape of Good Hope.
Some of the more recent of these European hunting savages—those who were perhaps in part our own forefathers, or who perhaps were of substantially the same ethnic type as the men of the older race strains in northeastern Asia, and even possibly of the American Indians—and many of their more remote predecessors were contemporaries of the lion, the horse, and the elephant. Different species of horse and elephant succeeded one another. The earlier ones were contemporaries of the hippopotamus and of not only the lion but the sabretooth. When the hairy elephant, the mammoth, was present, the fauna also often included the cave-lion, cave-hyena, cave-bear, wolf, boar, woolly rhinoceros, many species of deer (including the moose and that huge fallow deer, the Irish elk), horses, and the bison and the aurochs. The mammoth and woolly rhinoceros died out so recently that their carcasses are discovered preserved in the Siberian ice, and the undigested food in their stomachs shows that they ate northern plants of the kinds now common, and the twigs of the conifers and other trees which still flourish in the boreal realm of both hemispheres.
The lion was doubtless the most dreaded foe of the ancient European, just as he is to this day of certain African tribes. The Palæolithic hunters slaughtered myriads of wild horses, just as the ebony-hued hunters of Africa now slaughter the zebra and feast on its oily flesh. The spirited carvings and sketches of the hairy mammoth by the later Palæolithic cave-dwellers show that the elephant of the cold northlands had impressed their imaginations precisely as the hairless elephant of the hot south now impresses the imaginations of the tribes that dwell under the vertical African sun. The rhinoceros and wild cattle of the pine forests played in their lives the part played in the lives of our contemporaries, the hunting tribes of Africa, by the rhinoceros and the buffalo—the African wild ox—which dwell among open forests of acacias and drink from palm-bordered rivers. They saw no animal like that strange creature, the African giraffe; and several kinds of deer took the place of the varied species of bovine ruminants which, in popular parlance, we group together as antelopes.
Substantially the fauna of mighty beasts which furnished the means of livelihood, and also constantly offered the menace of death, to our European forefathers—or to the predecessors of our forefathers—was like that magnificent fauna which we who have travelled among the savages of present-day Africa count it one of our greatest pleasures to have seen. During the ages when the successive races of hunter-savages dwelt in Europe a similar magnificent fauna of huge and strange beasts flourished on all the continents of the globe except in Australia. In Europe it vanished in prehistoric times, when man had long dwelt in the land. In Africa south of the Sahara, and partially in spots of Asia, it has persisted to this day. In North America it died out before, or perhaps, as regards the last stragglers, immediately after, the coming of man; in South America it seems clear that it survived, at least in places, until he was well established.