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Revealing and Concealing Coloration 

 IN Birds and Mammals. By Theo- 

 dore Roosevelt. Bull. Am. Mus. 

 Nat. Hist. XXX, 1911, pp. 119-231. 



This paper is, in effect, a criticism of 

 Abbott H. Thayer's views in regard to the 

 protective value of the coloration of 

 animals, as set forth by Gerald H. Thayer, 

 in the volume entitled "Concealing Color- 

 ation in the Animal Kingdom."* 



An Appendix (pp. 221-231) presents a 

 reply to Mr. Thayer's criticism (Popular 

 Science Monthly, July, 1911) of earlier 

 comments on his work by Mr. Roosevelt, 

 in 'African Game Trails.' (App. E.) 



While admitting that some animals are 

 protectively colored, Mr. Roosevelt em- 

 phatically denies the truth of Mr. Thayer's 

 assertion that "patterns and utmost con- 

 trasts by color (not to speak of appen- 

 dages) on animals make wholly for their 

 'obliteration'." This controversion is 

 based primarily, indeed almost wholly, 

 on its author's field e.xperiences with 

 various species of birds and mammals 

 (particularly those ranked as game) in 

 North America and in Africa, which, as, they 

 serve to illustrate his point of view, are 

 given, often at much length. The paper, 

 therefore, is not merely a criticism, but 

 an important contribution to the subject 

 of the significance of animals' colors, con- 

 taining much new and original material. 

 Since the medium of publication will not 

 give to this article the circulation which 

 the widespread interest in its subject 

 warrants, we reprint here Mr. Roosevelt's 

 tentative 'Conclusions,' the most im- 

 portant of which are said to be ''those 

 which state the limitations of our present 

 knowledge." 



recapitulation 



"(i) Speaking roughly and generally, 

 there is a tendency for certain general 

 types of coloration to be found among all 

 the birds and mammals affected by the 

 *For a review of this work, see Bird-Lore, July- 

 August, 1910, pp. 153-155- 



same physical conditions. Those of the 

 tree tops are apt to have a lighter, brighter, 

 more varied coloration than those dwelling 

 in the more somber and uniform surround- 

 ings near the ground, beneath the forest 

 trees. There is a tendency for arctic and 

 alpine animals to be light-colored, and, in 

 many cases, white, in winter; there is a 

 tendency among desert animals to have 

 very pale tints; there is a tendency for 

 mammals and birds that dwell on or near 

 the ground in thick forests to be dull- 

 colored; and animals of the semi-arid 

 regions tend to be paler than those of cold 

 or temperate humid regions, which tend to 

 develop dark, lusterless hues, as compared 

 to the gorgeous hues so apt to be found 

 where humiditj^ and heat go together. 

 There are multitudes of exceptions to all 

 these tendencies, exceptions so numerous 

 that it is out of the question to speak of 

 the tendencies as laws that are always 

 binding; and there are many areas where 

 the types of coloration are so varied that 

 it is impossible to state the case generally, 

 the types of coloration being of what looks 

 like haphazard incongruity, showing that 

 many and conflicting principles of selec- 

 tion have been at work. 



"As regards this type of tendency, it is 

 possible that it represents the result of 

 natural selection picking out for the ma- 

 jority of birds and mammals colors which 

 may conceal them. It is possible, and to 

 my mind much more probable, that the 

 major part of the tendency is due, as 

 regards birds and mammals, not to natural 

 selection for this purpose at all, but to the 

 effect of physical surroundings upon all 

 the individuals of a very great number of 

 species. In any event, there remain as to 

 each locality many exceptions, — that is 

 there are in each locality many species 

 the coloration patterns of which have 

 developed along directly opposite lines to 

 those along which the coloration patterns 

 of most of the other species of the locality 

 have developed. Such exceptions include 

 the musk-ox. Raven and wolverine of the 



(255) 



