OF THE MAN-LIKE APES 219 



crown to the heel, so that they are shorter than the other 

 man-like Apes ; while the slenderness of their bodies 

 renders their mass far smaller in proportion even to this 

 diminished height. 



Dr. Salomon Miiller, an accomplished Dutch naturalist, 

 who lived for many years in the Eastern Archipelago, and 

 to the results of whose personal experience I shall fre- 

 quently have occasion to refer, states that the Gibbons 

 are true mountaineers, loving the slopes and edges of the 

 hills, though they rarely ascend beyond the limit of the 

 fig-trees. All day long they haunt the tops of the tall 

 trees ; and though, towards evening, they descend in 

 small troops to the open ground, no sooner do they spy 

 a man than they dart up the hill-sides, and disappear in 

 the darker valleys. 



All observers testify to the prodigious volume of voice 

 possessed by these animals. According to the writer 

 whom I have just cited, in one of them, the Siamang, " the 

 voice is grave and penetrating, resembling the sounds 

 goek, goek, goek, goek, goek ha ha ha ha haaaaa, and may 

 easily be heard at a distance of half a league." While the 

 cry is being uttered, the great membranous bag under 

 the throat which communicates with the organ of voice, 

 the so-called " laryngeal sac," becomes greatly distended, 

 diminishing again when the creature relapses into silence. 



M. Duvaucel, likewise, affirms that the cry of the Siamang 

 may be heard for miles making the woods ring again. So 

 Mr. Martin * describes the cry of the agile Gibbon as " over- 

 powering and deafening " in a room, and " from its strength, 

 well calculated for resounding through the vast forests." Mr. 

 Waterhouse, an accomplished musician as well as zoologist, 

 says, " The Gibbon's voice is certainly much more powerful 

 than that of any singer I have ever heard." And yet it is 

 to be recollected that this animal is not half the height of, 

 and far less bulky in proportion than, a man. 



There is good testimony that various species of Gibbon 

 readily take to the erect posture. Mr. George Bennett, f 

 a very excellent observer, in describing the habits of a 

 male Hylobates syndactylus which remained for some time 

 in his possession, says : "He invariably walks in the erect 

 posture when on a level surface ; and then the arms either 



* Man and Monkies, p. 423. 

 f Wanderings in New South Wales, vol. ii. chap, viii., 1834. 



