Cave Hunting / Researches on the evidence of caves respecting the early inhabitants of Europe

by William Boyd Dawkins

Must we then infer that in the pleistocene age the present habits of the musk-sheep, the reindeer, chamois, or ibex, were so changed as to allow them to flourish side by side with the hippopotamus, or vice versâ? Was the climate colder than it is now in Europe, or was it hotter? How was this singular association of northern and southern species brought about? The problem may be solved if we refer to the present distribution of animals in northern Asia and North America. As the winter comes on the arctic species gradually retreat southwards, and occupy the summer feeding-grounds of the elk, red-deer, and other creatures which are unable to endure the extreme severity of an arctic winter. In the spring the latter pass northwards, to enjoy the summer herbage of that area, which had been the winter-quarters of the arctic group of animals. Thus there is a continued swinging to and fro, over the same region, of the arctic and the temperate animals, and their remains must necessarily become more or less associated in the river-deposits, as well as in caves, where these last happen to occur. In northern Asia, and in America, the only boundary between the northern and temperate zoological provinces is that constituted by the fluctuating annual temperature, and there are no great hilly barriers running east and west, to prevent free migration to the north or south. If reference be made to the map, [Fig. 126], it will be seen that these conditions were amply satisfied in the pleistocene age. There were no physical barriers to migration, from the shores of the Mediterranean, as far north as Ireland. If the winter cold were severe, the reindeer and musk-sheep might advance as far south as the Pyrenees, and if the summer heat were intense there would be nothing to forbid the hippopotamus and the African carnivores advancing northwards. It seems to me that this is the only hypothesis which will satisfy all the facts of the case. The traces of glaciers and snow-fields where they are no longer found prove that the winter was severe; while the warmth of the summer seems to be sufficiently demonstrated by the presence of African species. Such extremes of temperature are presented, more or less, by all continents extending from high to low latitudes. They are modified in Europe at the present time by the warm current of the Gulf Stream, by the large area now occupied by the Mediterranean Sea, and by the submergence of the pleistocene lowlands on the Atlantic border.

The Temperate Group.

The third group of pleistocene mammalia consists of those still living in the temperate zones of Europe, Asia, and America:

Beaver.
Hare.
Rabbit.
Wild Cat.
Martin.
Stoat.
Weasel.
Otter.
Brown Bear.
Grizzly Bear.
Wolf.
Fox.
Horse.
Urus.
Bison.
Antelope saiga.
Wild Boar.
Stag.
Roe.

The range of many of these animals has been profoundly modified since the pleistocene age. The Antelope saiga of the Don and Volga lived as far to the west as Aquitaine. The grizzly bear, instead of being restricted to its American habitat in the Rocky Mountains, ranged over the whole of Siberia into Europe, as far to the south as the Mediterranean, and westwards as far as Gibraltar.

The urus[263] still lives in the larger domestic cattle, and the bison is represented in Europe by those which are protected by the forest laws of Lithuania, and in North America by the vast herds which are rapidly being exterminated, like the red Indian, by the rifles of the settlers. The horse was as abundant, and as widely spread over Europe, as the urus and the bison; according to Prof. Brandt it now no longer lives in Siberia in a wild state.

Species common to Cold and Tropical Climates.

The panther or leopard, which has been found alike in Britain, France, and Germany, has at the present day a most extended range through Africa, from Barbary to the Cape of Good Hope, and throughout Persia into Siberia. In this latter country Dr. Gothelf Fischer describes it as living in the same districts in the Altai Mountains, and in Soongaria, as the tiger. The fox and wolf are like instances of carnivores being able to endure great variations in temperature without being specifically modified. These three animals, therefore, tell us nothing as to the pleistocene climate.