A FOSSIL GROUND-SLOTH IN COLORADO 



By T. D. A. Cockerell 



The sloths are characteristic of the neo-tropical region. The modern 

 species, as is well known, are arboreal; three of them occur as far north 

 as Central America. In comparatively recent geological times, ground- 

 sloths of great size lived in South America, and even invaded a large 

 part of our own continent, extending as far as Pennsylvania and Oregon. 

 Many people are familiar with the bones of these extraordinary animals 

 as seen in museums, but until recently, few realized how nearly they 

 came to surviving up to our own times. In 1897 and during subsequent 

 years, a cave in Patagonia was explored, and found to contain not only 

 bones of a ground-sloth (Grypotherium) , but large pieces of skin with 

 the pale yellowish hair still attached. Some of these were sent to the 

 British Museum in London, where I have seen them. In the same cave 

 were remains of other extinct animals, including a horse, and also those 

 of man. It was believed by the explorers that men inhabited the cave, 

 and kept the Grypotherium in a state of domestication; but whether or 

 not this occurred, there is no doubt that they coexisted. 



Some time ago the late Mr. E. A. Lidle found on his farm, one mile 

 south of Walsenburg, Colorado, the skull of a large unknown animal. 

 Mrs. Lidle very kindly gave the specimen to the University Museum, 

 and it was brought to Denver and placed in Judge Henderson's hands 

 by Mr. Chas. Hayden. It was very evident that we had a specimen 

 of great value, representing something new to the Colorado list. Upon 

 investigation, it proved to be a ground-sloth, and after comparison with 

 Mr. Barnum Brown's account of Paramylodon nebrascensis , from the 

 Pleistocene near Hay Spring, Nebraska {Bull. Amer. Mus. Nat. Hist., 

 XIX, 1903, p. 569), I concluded that we had the second known example 

 of that species. There were, however, certain discrepancies, the most 

 serious being in the number of teeth in the upper jaw. The upper 

 dental series in Mylodon, as well as in the living sloths, is five. In our 

 skull, as may be seen from the figures, there are five teeth on each side; 



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