Chap. XVIII. Mammals — Development of Hair. 53 1 



instances. When stags, and the males of the wild goat, are 

 enraged or terrified, these crests stand erect ; u bnt it cannot be 

 supposed that they have been developed merely for the sake of 

 exciting fear in their enemies. One of the above-named an- 

 telopes, the Portax picta, has a large well-defined brush of black 

 hair on the throat, and this is much larger in the male than in 

 the female. In the Ammotragus tragelaphus of North Africa, a 

 member of the sheep-family, the fore-legs are almost concealed 

 by an extraordinary growth of hair, which depends from the 

 neck and upper halves of the legs ; but Mr. Bartlett does not 

 believe that this mantle is of the least use to the male, in whom 

 it is much more developed than in the female. 



Male quadrupeds of many kinds differ from the females in 

 having more hair, or hair of a different character, on certain 

 parts of their faces. Thus the bull alone has curled hair on the 

 forehead. 15 In three closely-allied sub-genera of the goat family, 

 only the males possess beards, sometimes of large size ; in tw^. 

 other sub-genera both sexes have a beard, but it disappears in 

 some of the domestic breeds of the common goat ; and neither 

 sex of the Hemitragus has a beard. In the ibex the beard is not 

 developed during the summer, and it is so small at other times 

 that it may be called rudimentary. 16 With some monkeys the 

 beard is confined to the male, as in the orang ; or is much larger 

 in the male than in the female, as in the Mycetes caraya and 

 Pithecia satanas (fig. 68). So it is with the whiskers of some 

 species of Macacus, 17 and, as we have seen, with the manes of 

 some species of baboons. But with most kinds of monkeys the 

 various tufts of hair about the face and head are alike in both sexes. 



The males of various members of the ox family (Bovidse), and 

 of certain antelopes, are furnished with a dewlap, or great fold ol 

 skin on the neck, which is much less developed in the female. ■ 



Now, what must we conclude with respect to such sexual 

 differences as these? No one will pretend that the beards of 

 certain male goats, or the dewlap of the bull, or the crests of 

 hair along the backs of certain male antelopes, are of any use 

 to them in their ordinary habits. It is possible that the im- 

 mense beard of the male Pithecia, and the large beard of the 

 male orang, may protect their throats when fighting; for 

 the keepers in the Zoological Gardens inform me that many 



14 Judge Caton on the Wapiti, p. 236 



* Transact. Ottawa Acad. Nat. lti See Dr. Gray's ' Cat. of Mam- 

 Sciences,' 1868, pp. 36, 40; Blyth, malia iu British Museum,' part iii. 

 'Land and Water,' on Capra x<ja- 1852, p. 144. 

 grus, 1867, p. 37. 17 Rengger, ' Stiugethiere,' &c. 5. 



15 ' Hunter's Essays and Observa- 14; Desmarest, c Mamma logie/ p, 

 lions,' edited by Owen, 1861, vol. i. 66. 



