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Descent of Man [ 1871]

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Author Topic: Descent of Man [ 1871]  (Read 2928 times)
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« Reply #180 on: February 10, 2009, 01:23:41 pm »

* Osphranter rufus, Gould, Mammals of Australia, 1863, vol. ii. On
the Didelphis, Desmarest, Mammalogie, p. 256.
  *(2) Annals and Magazine of Natural History, Nov., 1867, p. 325.
On the Mus minutus, Desmarest, Mammalogie, p. 304.
  *(3) J. A. Allen, in Bulletin of Mus. Comp. Zoolog. of Cambridge,
United States, 1869, p. 207. Mr. Dobson on sexual characters in the
Chiroptera, Proceedings of the Zoological Society, 1873, p. 241. Dr.
Gray on sloths, ibid., 1871, p. 436.

  The terrestrial Carnivora and Insectivora rarely exhibit sexual
differences of any kind, including colour. The ocelot (Felis
pardalis), however, is exceptional, for the colours of the female,
compared with those of the male, are "moins apparentes, le fauve,
etant plus terne, le blanc moins pur, les raies ayant moins de largeur
et les taches moins de diametre."* The sexes of the allied Felis mitis
also differ, but in a less degree; the general hues of the female
being rather paler than in the male, with the spots less black. The
marine Carnivora or seals, on the other hand, sometimes differ
considerably in colour, and they present, as we have already seen,
other remarkable sexual differences. Thus the male of the Otaria
nigrescens of the southern hemisphere is of a rich brown shade
above; whilst the female, who acquires her adult tints earlier in life
than the male, is dark-grey above, the young of both sexes being of
a deep chocolate colour. The male of the northern Phoca groenlandica
is tawny grey, with a curious saddle-shaped dark mark on the back; the
female is much smaller, and has a very different appearance, being
"dull white or yellowish straw-colour, with a tawny hue on the
back"; the young at first are pure white, and can "hardly be
distinguished among the icy hummocks and snow, their colour thus
acting as a protection."*(2)

  * Desmarest Mammalogie, 1820, p. 220. On Felis mitis, Rengger,
ibid., s. 194.
  *(2) Dr. Murie on the Otaria, Proceedings Zoological Society,
1869, p. 108. Mr. R. Brown on the P. groenlandica, ibid., 1868, p.
417. See also on the colours of seals, Desmarest, ibid., pp. 243, 249.

  With ruminants sexual differences of colour occur more commonly than
in any other order. A difference of this kind is general in the
strepsicerene antelopes; thus the male nilghau (Portax picta) is
bluish-grey and much darker than the female, with the square white
patch on the throat, the white marks on the fetlocks, and the black
spots on the ears all much more distinct. We have seen that in this
species the crests and tufts of hair are likewise more developed in
the male than in the hornless female. I am informed by Mr. Blyth
that the male, without shedding his hair, periodically becomes
darker during the breeding-season. Young males cannot be distinguished
from young females until about twelve months old; and if the male is
emasculated before this period, he never, according to the same
authority, changes colour. The importance of this latter fact, as
evidence that the colouring of the Portax is of sexual origin, becomes
obvious, when we hear* that neither the red summer coat nor the blue
winter-coat of the Virginian deer is at all affected by
emasculation. With most or all of the highly-ornamented species of
Tragelaphus the males are darker than the hornless females, and
their crests of hair are more fully developed. In the male of that
magnificent antelope, the Derbyan eland, the body is redder, the whole
neck much blacker, and the white band which separates these colours
broader than in the female. In the Cape eland, also, the male is
slightly darker than the female.*(2)

  * Judge Caton, in Transactions of the Ottawa Academy of Natural
Sciences, 1868, p. 4.
  *(2) Dr. Gray, Cat. of Mamm. in Brit. Mus., part iii., 1852, pp.
134-142; also Dr. Gray, Gleanings from the Menagerie of Knowsley, in
which there is a splendid drawing of the Oreas derbianus: see the text
on Tragelaphus. For the Cape eland (Oreas canna), see Andrew Smith,
Zoology of S. Africa, pls. 41 and 42. There are also many of these
antelopes in the Zoological Gardens.

  In the Indian black-buck (A. bezoartica), which belongs to another
tribe of antelopes, the male is very dark, almost black; whilst the
hornless female is fawn-coloured. We meet in this species, as Mr.
Blyth informs me, with an exactly similar series of facts, as in the
Portax picta, namely, in the male periodically changing colour
during the breeding-season, in the effects of emasculation on this
change, and in the young of both sexes being indistinguishable from
each other. In the Antilope niger the male is black, the female, as
well as the young of both sexes, being brown; in A. sing-sing the male
is much brighter coloured than the hornless female, and his chest
and belly are blacker; in the male A. caama, the marks and lines which
occur on various parts of the body are black, instead of brown as in
the female; in the brindled gnu (A. gorgon) "the colours of the male
are nearly the same as those of the female, only deeper and of a
brighter hue."* Other analogous cases could be added.

  * On the Ant. niger, see Proc. Zool. Soc., 1850, p. 133. With
respect to an allied species, in which there is an equal sexual
difference in colour, see Sir S. Baker, The Albert Nyanza, 1866,
vol. ii., p. 627. For the A. sing-sing, Gray, Cat. B. Mus., p. 100.
Desmarest, Mammalogie, p. 468, on the A. caama. Andrew Smith,
Zoology of S. Africa, on the gnu.

  The banteng bull (Bos sondaicus) of the Malayan Archipelago is
almost black, with white legs and buttocks; the cow is of a bright
dun, as are the young males until about the age of three years, when
they rapidly change colour. The emasculated bull reverts to the colour
of the female. The female kemas goat is paler, and both it and the
female Capra aegagrus are said to be more uniformly tinted than
their males. Deer rarely present any sexual differences in colour.
Judge Caton, however, informs me that in the males of the wapiti
deer (Cervus canadensis) the neck, belly, and legs are much darker
than in the female; but during the winter the darker tints gradually
fade away and disappear. I may here mention that Judge Caton has in
his park three races of the Virginian deer, which differs slightly
in colour, but the differences are almost exclusively confined to
the blue winter or breeding-coat; so that this case may be compared
with those given in a previous chapter of closely-allied or
representative species of birds, which differ from each other only
in their breeding plumage.* The females of Cervus paludosus of S.
America, as well as the young of both sexes, do not possess the
black stripes on the nose and the blackish-brown line on the breast,
which are characteristic of the adult males.*(2) Lastly, as I am
informed by Mr. Blyth, the mature male of the beautifully coloured and
spotted axis deer is considerably darker than the female: and this hue
the castrated male never acquires.
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