274 SEXUAL selection: mammals. PartIL 



CHAPTER XVIII. 



Secondary Sexual Characters of M.^w^m.'a— continued. 



Voice — Kemarkable sexual peculiarities iu seals — Odour — Deve- 

 lopment of the hair — Colour of the hair and skin — Anomalous 

 case of the female beinci; more ornamented than the male — 

 Colour and ornaments diTe to sexual selection — Colour acquired 

 for the sake of protection — Colour, though common to both 

 sexes, often due to sexual selection — On the disappearance of 

 spots and stripes in adult quadrupeds — On the colours and 

 ornaments of the Quadrumana — Summary. 



Quadrupeds use their voices for various purposes, 

 as a signal of danger, as a call from one member of 

 a troop to another, or from the mother to her lost 

 offspring, or from the latter for protection to their 

 mother ; but such uses need not here be considered. 

 We are concerned onlv with the difference between the 

 voices of the t\^■o sexes, for instance between that of 

 the lion and lioness, or of the bull and cow. Almost 

 all male auimals use their voices much more during 

 the rutting-season than at any other time ; and some, 

 as the giraffe and porcupine,^ are said to be completely 

 mute excepting at this season. As the throats {i.e. the 

 larnyx and thyroid bodies ^) of stags become periodi- 

 cally enlarged at the commencement of the breeding- 

 season, it might be thought that their powerful voices 

 must be then in some way of high importance to them ; 

 but this is very doubtful. From information given to 

 me by two experienced observers, Mr. McNeill and Sir 



1 Owen, 'Anatomy of Vertebrates,' vol. iii. p. 585. - Ibid. p. 595. 



