MAMMALS 



489 



southern part of North America, the Swine of the Old World 

 are replaced by the more specialized Peccaries. The smaller 

 Collared Peccary {Dicotyles torquatus), which has the wider 

 range, associates in small droves, while in the rather larger 

 White-lipped Peccary {D. labiatus), a purely South American 



Fig. 1003,— Hind and Fawn of Roe-Deer [Capreolns caprea) 



form, a very large number of individuals herd together. Both are 

 forest animals and lead a wandering life, and the young of both 

 species are devoid of the stripes so characteristic of Old World 

 Pigs. One, or at most two, young ones are born at a time, and 

 the milk-glands are reduced to a single pair. Possibly the number 

 of young may have undergone reduction as an adaptation to the 

 exigencies of a roaming life. 



The gregarious Hippopotamus {^Hippopotamus amphibius) pro- 



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