much more probable that the females are allured or excited by
particular males, who possess certain characters in a higher degree
than other males; but what these characters are, we can seldom or never
discover with certainty.
CHAPTER XVIII.
SECONDARY SEXUAL CHARACTERS OF MAMMALS continued.
Voice Remarkable sexual peculiarities in seals Odour Development of the
hair Colour of the hair and skin Anomalous case of the female being
more ornamented than the male Colour and ornaments due 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 only with the difference between the voices of the 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. Owen, Anatomy of Vertebrates, vol. iii. p. 585.), are
said to be completely mute excepting at this season. As the throats
(i.e. the larynx and thyroid bodies (2. Ibid. p. 595.)) of stags
periodically become enlarged at the beginning of the breeding-season,
it might be thought that their powerful voices must be somehow of high
importance to them; but this is very doubtful. From information given
to me by two experienced observers, Mr. McNeill and Sir P. Egerton, it
seems that young stags under three years old do not roar or bellow; and
that the old ones begin bellowing at the commencement of the
breeding-season, at first only occasionally and moderately, whilst they
restlessly wander about in search of the females. Their battles are
prefaced by loud and prolonged bellowing, but during the actual
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