34 Zoology of Colorado 



antelope nor a goat, but forms a distinct family, confined to North 

 America, where it has existed since Pleistocene times. The horns 

 are shed each year, but are formed on permanent horn-cores. 

 Warren notes that the first European to see this animal was Coro- 

 nado in 1535; but it was not until 1815 that it received a scientific 

 name. It is of course a typical member of the plains fauna, and 

 were it not for regulations made for its protection, it could not 

 long survive in the presence of modern firearms. The white rump 

 makes it very conspicuous to our eyes, and may serve a useful 

 purpose in assisting the antelope to keep together at night. The 

 suggestion has been made that from the position of a pursuing 

 wolf or mountain lion, the white patch against the sky breaks the 

 outline of the animal, and makes it hard to see clearly. The 

 artist Thayer was the leading exponent of such views, and while 

 he made important contributions to the theory of protective 

 coloration in animals, it must be said that he carried his ideas to 

 extremes*. 



It now remains to consider our deer or Cervidae. The 

 American elk or wapiti, Cervus canadensis, is closely related to 

 the red deer of Europe, but the antlers are distinctly different. 

 It is wrongly called the elk, this name belongs properly to the 

 moose. Formerly it was abundant in the mountains of Colorado, 

 but now it is greatly reduced in numbers. I n the vicinity of Boulder 

 it was exterminated, but has been established again from the 

 herds kept under protection in Wyoming. 



The American deer (Odocoileus) form a genus quite distinct 

 from the Old World deer, and in fact more related to the reindeer 

 and moose. The generic, specific and subspecific names used for 

 the Colorado deer were all invented by the eccentric naturalist 

 Rafinesque, who, about a hundred years ago, had a passion for 

 naming plants and animals. So eager was he for novelties, that 

 certain of his associates played practical jokes on him, describing 

 imaginary creatures for which he published names. His personal 

 peculiarities, and often reckless scientific work, caused him to be 

 regarded with very little favor, so that his life appeared to be a 



♦"'Thayer's Principle", which certainly is valid, explains why most mammals, birds 

 and fishes are darker above than below, or at any rate shows that they gain by this colora- 

 tion. Every fisherman knows, for example, that a live trout in the stream is more or less incon- 

 spicuous, appearing gray all over; but a dead fish, floating belly up, appears brilliantly white. 

 Thayer enunciated the principle that the light color below compensates for the lessened 

 illumination, the shaded parts appearing about as dark as the well lighted back. The result is 

 to make the animal inconspicuous. 



