THE GIBBONS 57 



into its cage ; and there can be but little doubt that such habits are natural to these 

 animals in their wild condition, when it is probable that birds thus captured consti- 

 tute an appreciable portion of their food. 



Although several of the species are found in the forests of the plains, the 

 hoolock appears to be almost if not exclusively restricted to those of hilly districts. 

 In marked contrast to the larger Man-like Apes, most of the gibbons go in large 

 flocks or droves, which may comprise from fifty to a hundred, or even more individ- 

 uals ; although, as with most gregarious animals, solitary males are occasionally ob- 

 served. The long arms are the chief agents in their active movements among the 

 trees ; and by their aid the distances they can swing from bough to bough, and thus 

 from tree to tree, are of surprising length. When going down hill they travel at an 

 extremely rapid pace, by swinging themselves in a downward direction from one 

 bough till they catch another on a lower level, and so from that to the next one. 



Although walking rapidly when on the ground, gibbons, as Mr. W. T. Blanford 

 tells us, can easily be overtaken by men. The same writer observes that, "when 

 walking on the ground, the hoolock rests on its hind-feet alone, with the sole flat on 

 the ground, and the great toe widely separated from the other digits. The arms 

 are usually held upwards, sometimes horizontally, their great length (as shown in 

 our illustration on p. 56) giving the animal a very peculiar aspect." 



We have already mentioned the fondness of the hoolock for small birds, and, in 

 addition to this kind of diet, gibbons subsist mainly on various fruits and leaves, as 

 well as young and tender shoots ; they also feed on insects and spiders, and the eggs 

 and callow nestlings of birds. 



The habit which makes the gibbons known to (as well as cordially hated by) 

 all who dwell in the districts which they frequent, is their custom of uttering at 

 morn and even cries of a peculiarly loud and somewhat unearthly nature. These 

 cries consist in the repetition of two syllables in quick succession ; and the name 

 hoolock is given to the Indian representative of the group in imitation of its cry. 



The late Mr. Blyth observes that, ' ' in all the genera of gibbon the thumbs of 

 both the hands and feet are separated from the other digits to the base of the meta- 

 carpal and metatarsal bones," and then states that this characteristic is also found 

 elsewhere among the Primates only in two genera of lemurs (Indris and Propithecus) . 

 The same writer goes on to say that at the time of his writing it was ' ' not gener- 

 ally understood that the long-armed apes are true bipeds when on the ground, ap- 

 plying the sole flatly, with the great toe widely separated from the other digits; the 

 hands are held up to be out of the way, rather than for balancing, even when 

 ascending a flight of steps, as I have seen repeatedly, but they are ever ready to 

 seize hold of any object by which the animal can assist itself along, even as a hu- 

 man being commonly grasps a banister when ascending a staircase. ' ' 



THE SIAMANG (Hylobates syndadylus) 



The siamang is the largest of all the gibbons, and since it also differs in certain 

 structural peculiarities, it may be taken first. This fine species is apparently con- 

 fined to Sumatra, and its habits were described many years ago by the French natu- 



