THE WHITE-HANDED GIBBON 



entire coat had become silvery, or stone, grey, except for a black stripe down the 

 middle line of the head. It does not, however, appear that this colour-change is 

 universal in the species ; for another captive specimen believed to be about a dozen 

 years old was wholly black. 



This is confirmed by the observations of a French traveller in the case of the 

 white-cheeked gibbon (H. leucogenys) of Annam and Siam, in which two distinct 

 colour-phases are noticeable. 



These gibbons commonly go about in parties of six or seven ; and while some 

 individuals are black with white whiskers and a band on the sides and lower part of 

 the face, in others the general colour is golden yellow with no white on the face. 

 That the two phases are specifically identical is certain, and it does not appear that 

 the light-coloured individuals eventually become dark, or vice versa. The natives, 

 it is true, have an idea that the light-coloured individuals are the females, but this 

 seems to be disproved by the fact that they are much less numerous than the black 

 ones ; and it thus appears probable that the species exhibits two distinct colour- 

 phases. 



Gibbons are almost wholly arboreal apes ; and in the trees they move about 

 mainly with the aid of their long arms, by means of which they swing themselves 

 from bough to bough, and thus from one tree to another, so that a whole troop will 

 traverse the forest without descending to the ground. So active and agile indeed 

 are these apes, that when confined in open cages they will catch birds on the wing, 

 which apparently form part of their food. In addition to these, gibbons subsist on 

 fruits of various kinds, leaves, young shoots, insects, and spiders. 



All gibbons have a remarkably powerful double-note cry, like ku-lok, which 

 has a wailing sound, and awakes the echoes in the early morning and again at even- 

 ing in the forests inhabited by these apes. At a distance the cry has some faint 

 resemblance to the human voice ; but at close quarters it is enough to drive the 

 traveller, when resting in his tent, well-nigh distracted. 



47 



