214 THE DESCENT OP MAN. 



deimatous animals differ very little or not at all, and, as far as 

 known, they are not polygamists. Nor have I heard of any 

 species in the Orders of Cheiroptera, Edentata, Insectivora and 

 Rodents being polygamous, excepting that amongst the Rodents, 

 the common rat, according to some rat-catchers, lives vrith several 

 females. Nevertheless the two sexes of some sloths (Edentata) 

 difter in the character and color of certain patches oi hair on 

 their shoulders." And many kinds of bats (Cheiroptera) present 

 v/ell-marked sexual differences, chiefly in the males possessing 

 odoriferous glands and pouches, and by their being of a lighter 

 color." In the great order of Rodents, as far as I can learn, 

 the sexes rarely differ, and when they do so, it is but slightly in 

 the tint of the fur. 



As I heard from Sir Andrew Smith, the lion in South Africa 

 sometimes lives with a single female, but generally with more, 

 and, in one case, was found with as many as five females; so that 

 he is polygamous. As far as I can discover, he is the only polyg- 

 amist amongst all the terrestial Carnivora, and he alone pre- 

 sents well-marked sexual characters. If, however, we turn to the 

 marine Carnivora, as we shall hereafter see, the case is widely 

 different, for many species of seals offer extraordinary sexual 

 differences, and they are eminently polygamous. Thus, accord- 

 ing to Peron, the male sea-elephant of the Southern Ocean always 

 possesses several females, and the sea-lion of Forster is said to be 

 surrounded by from twenty to thirty females. In the North, the 

 male sea-bear of Steller Is accompanied by even a greater number 

 of females. It is an interesting fact, as Dr. Gill remarks,'' that in 

 the monogamous species, "or those living In small communities, 

 "there is little difference In size between the males and females; 

 "in the social species, or rather those of which the males have 

 "harems, the males are vastly larger than the females." 



Amongst birds, many species, the sexes of which differ greatly 

 from each other, are certainly monogamous. In Great Britain 

 we see well-marked sexual differences, for instance, in the wild- 

 duck which pairs with a single female, the common blackbird, 

 and the bullfinch which is said to pair for life. I am informed 

 by Mr. Wallace that the like is true of the Chatterers or Cot- 

 ingidas of South America, and of many other birds. In several 

 groups I have not been able to discover whether the species are 

 polygamous or monogamous. Lesson says that birds of paradise, 

 so remarkable for their sexual differences, are polygamous, but 

 Mr. Wallace doubts whether he had sufficient evidence. Mr. Bal- 

 vin tells me he has been led to believe that humming-birds are 

 polygamous. The male widow-bird, remarkable for his caudal 



12 Dr. Gray, in 'Annals and Mag. of Nat. Hist.' 1S71, p. 302. 



" See Dr. Dobson's excellent paper, in 'Proc. Zoolog. Soc' 1873, p. 241. 



'^The Bared Seals, 'American Naturalist,' vol. iv., Jan. 1871. 



