EXTINCT SLOTHS

Taranaki Daily News, 22 September 1931, Page 14

EXTINCT SLOTHS

B AMERICAN FINDS. WHAT A CAVE HID. Among the exhibits which attracted much attention at the 1930 exhibition of the results of the research activities of Carnegie Institution of Washington was one comprising a number of objects found during the past year in . Gypsum Cave, Nevada. These consisted of pieces of the hide of the extinct ground-sloth, Nothrotherium, covered with masses of coarse, reddish-brown hair; various bones of the same animal, ■ including those of the right hind foot, ' its phalanges terminating in enormous claws with their horny sheath still in- ' tact; and a number of objects attributed to primitive man such as bits of ■ charcoal, burnt sticks, apparently once used as torches, flint, dart-points, and ‘ crude wooden dart-shafts, decorated with quite elaborate patterns in red and black, blue and green. Although the discovery of parts of • skeletons of several ground sloths, and abundant evidence that Gypsum Cave was once occupied in numbers by these creatures, as well as by species of camel, horse, and other animals now extinct, is of definite scientific value, nevertheless, this and other species of ground sloths are fairly well known from rather complete remains found in Brazilian caves and in the asphalt beds of Rancho La Brea in California and in other localities in North America. Indeed, more than a year ago an unusually complete skeleton of Nothrotherium, obtained from a guano deposit at Aden Crater, New Mexico, and remains of epidermal structures found with the skeleton, were described by Professor Lull of Yale University. Moreover, the discovery of dart-shafts, flint points and other evidence of the presence of primitive man, though not without -interest, in itself is not of exceptional importance for the caves of the South-west arc yielding a wealth of material of this character. It was not the discovery of the remains of ground sloths in Gypsum Cave that had set the scientists all agog, nor the discovery of objects of human workmanship, primitive though they be, but the fact that these were found associated in such manner as to indicate that man may have been contemporaneous on this continent with these ponderous, show-maving 'beasts, believed to have become extinct in North America before the end of the Pleistocene Period, the period frequently referred to as the Great Ice Age. It was doubtless this consideration which prompted President Merriam of Carnegie Institution to say last summer, after he had examined the material first obtained: “There is no doubt regarding the great importance of this find. It ranks among the most interesting discoveries in archaeology in America.” Had a discovery of this nature been made in central or western Europe under conditions pointing to Pleistocene time, no great excitement would have been caused, for the fossil records of these regions already afford -convincing evidence that man of the modern type had appeared in Europe before the close of the Pleistocene Period which ended, according to generally accepted views, from 15,000 to 30,000 years ago. In America, however, the case is different. The opinion has been held by many that the Americas were peopled at a relatively late time by races presumably coming in from Asia by way of Bering Strait. Climatically, conditions in North America during Pleistocene time were much the same as those which prevailed in Europe. A great belt of ice encircled the Pole, the frontal margins of which successively pushed southward, overriding much of the land even well down towards the middle of the two continents, only to retire at intervals leaving great areas in each covered by masses of sand, gravel and boulders of all sizes up to many tons in weight, as the meltting ice released its load. The great oscillations of climate at- ' tending the repeated advances and partial retreats of the polar ice sheets, variations which ranged between a cold' of Arctic severity to a temperature probably milder than that now prevailing in these regions, profoundly affected the. , plant and animal life of the Northern , Hemisphere. Types adapted to the milder climate which prevailed before Pleistocene time were exterminated or else crowded down to warmer latitudes. Thus, northern forms migrated southwards during the cold intervals, while southern forms pushed their way northwards during the warmer episodes. Apparently, also, the eastern and western highways of distribution and of inter- i change were such, and the time involved j so great, that essentially the same types f of plants and animals came to occupy • < the two continents. i Thus it camo about that tho immediate progenitors of most of the mammal- 1 ian forms of present-day animal life I were widely distributed over the North- < era Hemisphere during Pleistocene days, I