20 XOIITII AMERICAN FAUNA 60, FISH AND WILDLIFE SERVICE 



becomes loii^rer in the winter. In the subgenus Euprocyon — inhabiting 

 tropical countries — no definite seasonal molt seems apparent. 



VARIATION 



Variation in the raccoons is assignable to several categories, of 

 which perhaps the most obvious are geographic and individual. 



GEOGRAPHIC VARIATION 



The raccoons are ])elieved to intergrade throughout the vast range 

 of the species Procyon lofor on the North American mainland, and the 

 component subspecies are the expression of geographic variation in 

 size, weight, color, and minor details of structure in response to 

 environmental and genetic influences. Some of the insular forms 

 present a greater degree of dift'erentiation, evidently due to isolation, 

 and are regarded as distinct species. The largest form of the genus, 

 Procyon lotor excehus, inhabits interior valleys, principally the Snake 

 River Valley in southeastern Washington, eastern Oregon, and 

 southern Idaho. Large, but less extreme, geographic races occupy 

 the other Western States and the mainland of Middle America. 

 These give way to smaller subspecies in the eastern United States, 

 the minimum size being reached by those living on the Florida Keys. 

 Maria Madre and Maria Magdalena of the Tres Marias Islands 

 Group oft* western Mexico are occupied by Procyon insularis, a large 

 form regarded as specifically distinct from the mainland animal. 

 Small species of raccoons inhabit New^ Providence Island in the 

 Bahamas, and Guadeloupe and Barbados Islands of the Lesser 

 Antilles. The smallest species of raccoon known was well named 

 Procyon pygmaeus from Cozumel Island, Yucatan. 



Geographic variation in color in the raccoons is limited mainly to 

 the general tone and to the relative development of the black mask 

 and other facial markings. The paler subspecies, such as Procyon 

 lotor pallidus, inhabit the thinly timbered desert areas in the Colorado 

 River Valley and adjoining territory, while darker races have de- 

 veloped in the eastern United States and in densely forested regions 

 of heavy precipitation in Central America. In considering the pallid 

 coloration of raccoons from desert areas, as along the Colorado River, 

 it should be understood that these animals are restricted to the 

 vicinity of water, yet they share the general pallor that is a marked 

 characteristic of the mammals of the region as a whole. 



IINDIVinUAL VAHIVTION 



By individual variation reference is made to all the degrees of 

 divergence from a typical mean exhibited by large series of conspecific 

 skins and skulls from any given locality. In the raccoons the range 

 of this variation in size, color, and cranial details is about the same as 



