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Show 274 SEXU.lili SELECTION : MAMMALS. PART If. CHAPTER XVIII. SEcONDARY SEXUAL CnARAC'l'ERS OF MaMMALf;-continued. Voice- Remarkable sexual peculiarities in seals- Odour- Development of the hair-Colour of the hair and skin-Anomalous. ~se of the female beincr more ornamented than the maleColour and ornaments dt~ 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 tho colours and ornaments of the Quadrnmana-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. vVe are concerned only with the difference between the voices of the two sexes, for instance between that of the lion and lioness, or of the bull and cow. Almost all male animals use their voices much more during the rutting-season than at any other time ; and some, as the giraffe and porcupine, 1 are said to be completely mute excepting at this season. As the throats (i.e. the larnyx and thyroid bodies 2 ) of stags become periodically enlarged at the commencement of the breedingseason, 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 I'· Owen, 'Anatomy of Vortcbmtcs,' vol. iii. p. 585. ~ Ibid. p. 505. CllAl'. xvnr. YOCAL ORGANS. 275 P. Egerton, it seems that young stags under three years old do not roar or bellow; and that the old ones begin bellowing at tho commencement of the breedingseason, at first only occasionally and moderately, whilst Tthle y. rebs tlesl sly wander about in sea1·ch of tho ~em· 1 l' a es. 1~n· att es m:e prefaced by loud and prolonged bel-low. mg, but dun~g the actual conflict they arc silent. Ammals of all kmds which habitually use the' · . . 11' VOICes, utter vanous noises under any strong emotion. as when enraged and prepar~ng to fight; but this m~y merely be the result o:f then· nervous excitement, which leads to the spasmodic contraction of almost all the muscles of ]t h· e 1b oddy , a· s when a man grinds his teeth and c1 e nc h es 11s 1an s m rage or agony. No doubt stags challenge each other to mortal combat by bellowing· b t 't · 1'1 l ' u 1 IS not 1 re y t~1at this habit could have led through scx~al selectiOn, that is Ly the loudest-voiced males havmg. be~n the most successful in their conflicts, to the per~orhcal enlargement of the vocal orgnns; for the s~ags WJth the most powerful roices, unless at tl 1e same tune the strongest, best-armed, and most courageous w?uldnot have .gained any ad vantage over their rival~ mth wea~er vmccs. The stags, moreover, which had weaker voices, though not so well able to chaUenge other stags~ woulcl have been drawn to the place of combat as certmnly as those with stronger voice~. It is possible tha~ the ro~ring of the lion may be o~ some actual service to him in striking terror into Ins adversary; for when enraged he likewi ,e erects his mane and thus instinctively tries to make himself a _ pear as terrible as possible. But it can hardly be su:posed tb~.t the bellowing of tho stag, even if it be of any serviCe to him in this way, cau have been important enough to have led to the periodical cnlarO'ement of the throat. Some writers suggest that rho '1.' 2 |