232 SEXUAL SELECTION: MAMMALS. [Part II. 



actually been saved from acquiring such weapons, owing 

 to their being useless and superfluous, or in some way in- 

 jurious. On the contrary, as they are often used by the 

 males of many animals for various purposes, more especially 

 as a defence against their enemies, it is a surprising fact 

 that they are so poorly developed or quite absent in the 

 females. ' No doubt with female deer the development 

 during each recurrent season of great branching horns, 

 and with female elephants the development of immense 

 tusks, would have been a great waste of vital power, on 

 the admission that they were of no use to the females. 

 Consequently variations in the size of these organs, lead- 

 ing to their suppression, would have come under the con- 

 trol of natural selection, and, if limited in their transmission 

 to the female offspring, would not have interfered with their 

 development through sexual selection in the males. But 

 how on this view can we explain the presence of horns in 

 the females of certain antelopes, and of tusks in the 

 females of many animals, which are only of slightly less 

 size than in the males ? The explanation in almost all 

 cases must, I believe, be sought in the laws of transmis- 

 sion. 



As the reindeer is the single species in the whole fam- 

 ily of Deer in which the female is furnished with horns, 

 though somewhat smaller, thinner, and less branched than 

 in the male, it might naturally be thought that they must 

 be of some special use to her. There is, however, some 

 evidence opposed to this view. The female retains her 

 horns from the time when they are fully developed, namely, 

 in September, throughout the winter, until May, when she 

 brings forth her young ; while the male casts his horns 

 much earlier, toward the end of November. As both 

 sexes have the same requirements and follow the same 

 habits of life, and as the male sheds his horns during the 

 winter, it is very improbable that they can be of any spe- 



