CLIMATE AND RACE — COON 279 



genetics, and cultural anthropology in time and space. With all due 

 respect to my colleagues I know of no one individual who can meet 

 these qualifications. Hence it looks as though Allen's prediction would 

 have to be still further delayed. 



Still the problem can be stated. According to the modern concept 

 of species formation expounded by Mayr and others, most animal 

 species are polytypic — that is, they extend over a varied geographical 

 range, and in a number of observable characteristics the local popula- 

 tions vary gradually from one end of the spatial range to another. A 

 minority of species is monotypic — that is, lacking in geographical 

 variation in any known character. Monotypic species are usually 

 confined to small and isolated areas. Man is a polytypic species. 

 Cases of genuine isolation, like that of the Polar Eskimo, are rare and 

 probably of short duration. Like other polytypic species man varies 

 from place to place, and the different forms which his variations take 

 seem, in some, but not all, instances, to follow the same ecological 

 rules as do those of other warm-blooded animals. Three of these 

 rules, the longest known, concern us here. 



1. Gloger''s rule. — "In mammals and birds, races which inhabit 

 warm and hiuiiid regions have more melanin pigmentation than races 

 of the same species in cooler and drier regions ; arid regions are char- 

 acterized by accumulation of yellow and reddish-brown phaeomelanin 

 pigmentation." (Dobzhansky, 1951.) "The phaeomelanins are sub- 

 ject to reduction in cold climate, and in extreme cases also the eumel- 

 anin" (polar white) . (Mayr, 1942, p. 90.) 



2. BergmanrCs rule. — "The smaller-sized geographic races of a spe- 

 cies are found in the warmer parts of the range, the larger sized 

 races in the cooler districts." (Ibid., p. 283.) 



3. Allen's rule. — Protruding body parts, such as tails, ears, bills, 

 extremities, and so forth, are relatively shorter in the cooler parts of 

 the range of the species than in the warmer parts." (Idem.) 



The rest of this paper will be devoted to an inquiry into the possible 

 application of these three rules to man. They cannot be called laws 

 in the sense of Newton's Law or the Second Law of Thermodynamics, 

 although these two, and other well-established physical principles, no 

 doubt contribute to whatever validity they may be shown to possess. 

 That no one simple law is involved in any instance is shown by Eensch's 

 discovery (1929, 1936-37) that these three rules, along with several 

 others of his own formulation (Rensch's clutch rule and hair rule, for 

 example) are subject to 10 to 30 percent of exceptions. They cannot 

 be called laws, because controls have not been sufficiently established 

 to eliminate outside functions, and because not enough experiments 

 have been made. However, a hibernating animal that defies Berg- 

 mann's rule is no more a valid exception to it than a helicopter is to 



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