The apes and monkeys already appear to have been differentiated at the beginning of the Cainozoic Age, and there are a number of Oligocene and Miocene apes whose relations to one another and to the human line have still to be made out. Among these we may mention Dryopithecus of the Miocene Age, with a very human-looking jaw. In the Siwalik Hills of northern India remains of some very interesting apes have been found, of which Sivapithecus and Palæopithecus were possibly related closely to the human ancestor. Possibly these animals already used implements. Charles Darwin represents baboons as opening nuts by breaking them with stones, using stakes to prize up rocks in the hunt for insects, and striking blows with sticks and stones.[21] The chimpanzee makes itself a sort of tree hut by intertwining branches. Stones apparently chipped for use have been found in strata of Oligocene Age at Boncelles in Belgium. Possibly the implement-using disposition was already present in the Mesozoic ancestry from which we are descended.[22]
§ 2
Among the earliest evidences of some creature, either human or at least more man-like than any living ape upon earth, are a number of flints and stones very roughly chipped and shaped so as to be held in the hand. These were probably used as hand-axes. These early implements (“Eoliths”) are often so crude and simple that there was for a long time a controversy whether they were to be regarded as natural or artificial productions.[23] The date of the earliest of them is put by geologists as Pliocene—that is to say, before the First Glacial Age. They occur also throughout the First Interglacial period. We know of no bones or other remains in Europe or America of the quasi-human beings of half a million years ago, who made and used these implements. They used them to hammer with, perhaps they used them to fight with, and perhaps they used bits of wood for similar purposes.[24]
But at Trinil, in Java, in strata which are said to correspond either to the later Pliocene or to the American and European First Ice Age, there have been found some scattered bones of a creature, such as the makers of these early implements may have been. The top of a skull, some teeth, and a thigh-bone have been found. The skull shows a brain-case about half-way in size between that of the chimpanzee and man, but the thigh-bone is that of a creature as well adapted to standing and running as a man, and as free, therefore, to use its hands. The creature was not a man, nor was it an arboreal ape like the chimpanzee. It was a walking ape. It has been named by naturalists Pithecanthropus erectus (the walking ape-man). We cannot say that it is a direct human ancestor, but we may guess that the creatures who scattered these first stone tools over the world must have been closely similar and kindred, and that our ancestor was a beast of like kind. This little trayful of bony fragments from Trinil is, at present, apart from stone implements, the oldest relic of early humanity, or of the close blood relations of early humanity, that is known.
While these early men or “sub-men” were running about Europe four or five hundred thousand years ago, there were mammoths, rhinoceroses, a huge hippopotamus, a giant beaver, and a bison and wild cattle in their world. There were also wild horses, and the sabre-toothed tiger still abounded. There are no traces of lions or true tigers at that time in Europe, but there were bears, otters, wolves, and a wild boar. It may be that the early sub-man sometimes played jackal to the sabre-toothed tiger, and finished up the bodies on which the latter had gorged itself.[25]
§ 3
After this first glimpse of something at least sub-human in the record of geology, there is not another fragment of human or man-like bone yet known from that record for an interval of hundreds of thousands of years. It is not until we reach deposits which are stated to be of the Second Interglacial period, 200,000 years later, 200,000 or 250,000 years ago, that another little scrap of bone comes to hand. Then we find a jaw-bone.
This jaw-bone was found in a sandpit near Heidelberg, at a depth of eighty feet from the surface,[26] and it is not the jaw-bone of a man as we understand man, but it is man-like in every respect, except that it has absolutely no trace of a chin; it is more massive than a man’s, and its narrowness behind could not, it is thought, have given the tongue sufficient play for articulate speech. It is not an ape’s jaw-bone; the teeth are human. The owner of this jaw-bone has been variously named Homo Heidelbergensis and Palæoanthropus Heidelbergensis, according to the estimate formed of its humanity or sub-humanity by various authorities. He lived in a world not remotely unlike the world of the still earlier sub-man of the first implements; the deposits in which it is found show that there were elephants, horses, rhinoceroses, bison, a moose, and so forth with it in the world, but the sabre-toothed tiger was declining and the lion was spreading over Europe. The implements of this period (known as the Chellean period) are a very considerable advance upon those of the Pliocene Age. They are well made but very much bigger than any truly human implements. The Heidelberg man may have had a very big body and large forelimbs. He may have been a woolly strange-looking creature.