There is a world somewhere between reality and fiction. Although ignored by many, it is very real and so are those living in it. This forum is about the natural world. Here, wild animals will be heard and respected. The forum offers a glimpse into an unknown world as well as a room with a view on the present and the future. Anyone able to speak on behalf of those living in the emerald forest and the deep blue sea is invited to join.
The Cave Bear Story by Bjorn Kurten... Few extinct animals are known from such a great number of fossil remains as the cave bear. Because there is such a wealth of information, a uniquely detailed picture of its anatomy and life history can be constructed. The same may be said of the origin of the cave bear. Almost every stage in its history can be traced back, in unbroken lineage, for 5 million years or more. And we occasionally get glimpses of still older stages in its long history.
The Cave Bear Story... Among the small creatures ( Miocene Europe ) we also find remains of a creature about the size of a fox terrier, but which is neither dog, cat, or weasel. Latter-day scientists have given it the name 'Ursavus elmensis'. It is with this small creature that the true bear line of evolution may be said to start. Actually, we can go still further back in time; we know the ancestor of Ursavus, but it is more doglike than bearlike, and so many scholars place it in the dog family. With Ursavus we come to the first animal definitely reckoned to be a bear, though indeed a very small and primitive one.
The Cave Bear Story... The early hipparion-fauna of the Old World coexisted with the last and largest of the primitive Ursavus bears. But at this time there was also living a somewhat more advanced type of bear. The only evidence of its existence discovered so far is a single tooth. It comes from Spain, from the remarkable site of Can Llobateres on the outskirts of the thriving city of Sabadell, near Barcelona. The immense harvest of fossil bones from this location includes at least seventy species of mammals, among which the abundance of gibbons, and large apes is particularly striking. Clearly, when all these animals were living 12 million years ago, Can Llobateres was still a subtropical area with great forests inhabited by many remarkable beasts now long extinct. The bear, as noted, is represented by a single molar tooth, but it happens to be one of the most distinctive in shape. The Can Llobateres bear was clearly more advanced than the contemporary ursavi, yet had not attained the evolutionary grade of a true 'Ursus'. So we have called this creature Protursus simpsoni. It was an animal about the size of a sheepdog; it probably descended from one of the earlier ursavi, such as Ursavi elemensis; and it was probably ancestral to Ursus. Little more can be said about it, until scientists find more material.
The Cave Bear Story... About 10 million years ago there was a marked change in world climate, which started to become drier. In many areas the mighty forests that had existed for so many millions of years died out, and savannas, steppes, and deserts spread widely. During this process, many of those animals that were adapted for a life in the forests fared badly. but those that lived on the open plains - antelopes, hipparions, and many others - entered a golden age. Bears are generally forest-living animals, and so we lose sight of some of them for the next few million years. We do know that the last and largest of the ursavi struggled on for some time before becoming extinct. We also know that the great Indarctos bears, which had risen as an early side-branch from the ursavi, spread into North America. But the evolutionary line that was initiated by the Protursus of Can Llobateres excaped our search, and the Miocene epoch will have come to an end before we meet it again.
The Cave Bear Story... We are now in the Pliocene epoch of earth history, starting some 5 to 6 million years ago. Our stage moves to Roussillon and Perpignan in the south of France ( and a contemporary site in Hungary ), where we find the first member of the genus Ursus. He bears the name 'Ursus minimus', and he is indeed the smallest known member of his genus and the most primitive too. He probably reached about the size of the living sun bear or Malay bear, which is the smallest of the living bears. At the time of Ursus minimus, the world was already on the threshold of the Ice Age. The forests where the first Ursus lived were quite different from the subtropical world of the Miocene ursavi.
The Cave Bear Story... In the early Villafranchian age ( 4 million years ago ) we still see Ursus minimus around, although he has changed a bit. He is somewhat larger than in the old times, and there have also been small, all but imperceptible, changes in his teeth. bears of this kind were widely distributed in the Old World, and recent finds in North America show that this species, or a very closely related one, was present there too. The two living species of black bear, the American ( Ursus americanus ) and the Himalayan ( Ursus thibetanus ) are probably descended from Ursus minimus.
The Cave Bear Story... By mid-Villafranchian times, some 2.5 million years ago, changes had proceeded far enough for Ursus minimus to give rise to a new species: the Etruscan bear, Ursus etruscus, the typical bear of the later Villafranchian. This speicies, whose characters are known through numerous remains in Spain, France, and Italy, was also present in China. In the flesh it probably resembled living black bears, though of course its color is unknown to us. Through the Villafranchian age this trend towards large size continued in the Etruscan bear; late Villafranchian forms are larger than mid-Villafranchian ones. The Etruscan bear is now as big as the living European brown bear, but it still carries the full complement of premolars ( albeit very small ones ) as an inheritance from the ancient ursavi and their doglike predecessors.
The Cave Bear Story... With the Tiglian interglacial, the Villafranchian age may be said to have come to an end: the prelude is over, and we are in the true Ice Age, the Pleistocene epoch of earth history. The Tiglian comes to a close. In the Alps mountain glaciers grow larger, coalesce, and send icy tongues down along the valleys. They grow ever greater and finally engulf the mountain range, with only a few bare peaks protruding out of the frozen waste. Glaciation is upon the world again, and this glaciation is called the Donau ( Danube ). Mant thousands of years pass with great tracts of the earth's surface as if immobilized in icy stillness. Then, once more, comes the swing. Glaciers melt and retreat, and areas recently under ice emerge to be conquered by plants and animals.
The Cave Bear Story... Among those animals who return to the lands of their Tiglian ancestors we find the descendant of the Etruscan bear. Again, evolution has taken a step forward, for he has changed. The anterior premolars, already very small in the Etruscan bear, are now almost gone; in some individuals all are lacking, but many retain one or more of these vestigial structures. Accompanying this change there is a tendency to a doming forehead, Foreshadowing the cave bear condition. This new species of bear is called 'Savin's bear', Ursus savini, and it lived about 1 million years ago in the interglacial termed the Waalian. Its remains have been found in various sites, for example Bacton in East Anglia, England, and the Hundsheim fissure in Austria. Although large and impressive enough, these early cave bears were still much smaller, on average, than the true cave bear.
The Cave bear Story... The pendulum swings again: cold conditions are back. The Gunz glaciation reached its culmination some 800,000 to 900,000 years before the present. There is some evidence that in one of the cold phases that make up the Gunz, longer-limbed bears, perhaps from the East, pressed into Europe to supplant temporarily the stocky-legged Savin's bear, but the problem of whether this intruder was a distinct species or just a steppe race of the early cave bear has not been settled. The latter alternative appears perhaps the most likely one. The ice melts and the world is green once more as the wind of the Cromerian interglacial blows over the European scene. And man meets bear. The bear of the Cromerian may well be regarded as a full-fledged cave bear. True, it is still a little smaller, although clearly larger and longer-jawed than its ancestor the Savin's bear. Also, the vaulting of its forehead is less prominent and its grinders are not quite as expanded as in the late Pleistocene animal. And so it has been given a species name of its own, and is known as 'Deninger's bear', Ursus deningeri. But there is much to say for just regarding it as an early, primitive race of Ursus spelaeus. We may compromise by calling it Deninger's cave bear.
The Cave Bear Story... But there is no rest for the pendulum of climate. Again there is a swing to cold conditions - the Elster glaciation - and then back to warm - the Holsteinian interglacial. We are now roughly 300,000 years before the present, and the bear in existence is Ursus spelaeus without any doubt. His remains have been found in caves in Germany and France, and especially interesting is the find of a good skull in the river gravels at Swanscombe outside London, England, which have also yielded a skull of early man.
The Cave Bear Story... The recounting of the long evolutionary history of the cave bear line may seem tedious, but it should give some understanding of how complete the evidence of its evolution really is. From the early Ursus minimus of 5 million years ago to the late Pleistocene cave bear, which became extinct only a few thousand years ago, there is a perfectly complete evolutionary sequence without any real gaps. The transition is slow and gradual throughout, and it is quite difficult to say where one species ends and the next begins. Where should we draw the boundary between Ursus minimus and Ursus etruscus, or between Ursus savini and Ursus spelaeus? The history of the cave bear becomes a demonstration of evolution, not a hypothesis or theory but as a simple fact of record.
The Cave Bear Story... Still, it has been noted that the Ursus line threw off two side-brances, leading to the American and Himalayan black bears, respectively. In some respects these bears remained near the evolutionary level of the Etruscan bear. We must now take note of another branch; the brown bear, Ursus arctos. This animal differs from the Etruscan bear in its general larger size, its somewhat longer and slenderer limb bones, and the greater reduction of its front premolars - to take the most important differences. The first brown bears in the fossil record appeared in China, in deposits dating back approximately to the Elster glaciation, about half a million years ago. Thus it would seem that the European population of Etruscus bears gave rise to the cave bears, whereas the Asiatic population evolved into brown bears.
The Cave Bear Story... At a much later date the Asiatic daughter species, the brown bear, invaded Europe. From the Holsteinian interglacial on, or since about a quarter of a million years ago, both the cave bear and the brown bear were present in Europe. The brown bear also invaded North America, where it now lives in the guise of the grizzly and ( Alaskan ) brown bears. They are now regarded as local races of the species Ursus arctos, and their history in North America ( except Alaska ) is quite short, geologically speaking.
The Cave Bear Story... We still have to account for one species of the Ursus line. This is the polar bear, Ursus maritimus, which is now highly specialized for a completely carnivorous mode of life, but which in its anatomy carries a clear brown bear heritage. The polar bear may have arisen from brown bear populations on the Arctic coast of Siberia, which specialized in seal hunting. It apparently is the youngest of all the living species of bears, for the earliest known polar bear find is less than 100,000 years old ( and incidentally comes from Kew in London ).
