6o 
APES AND MONKEYS. 
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 
metacarpal and metatarsal bones,” and then states that this character 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 generally 
understood that the long-armed apes are true bipeds when on the ground, applying 
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 
human being commonly grasps a banister when ascending a staircase.” 
The Siamang (Hylobates syndactylus). 
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 
confined to Sumatra, and its habits were described many years ago by the French 
naturalist Duvaucel. The animal, when full-grown, stands a little over three 
feet in height when in the upright position. It is of a uniform glossy black 
colour, with the exception of a grey or whitish beard; the hair on the body 
and limbs being comparatively long. The hair on the fore-arm is directed upwards 
towards the elbow, as in the larger Man-like Apes, whereas the other members of the 
genus have it pointing towards the wrist. There are, moreover, two other features 
in which this species differs from the other gibbons. The first of these peculiarities, 
and the one from which the animal derives its scientific designation, is the 
circumstance that the second and third toes of the foot are joined together by a thin 
web of skin, reaching in the male as far as the last joint, but in the female only to 
the middle one. The second distinctive peculiarity of the siamang is the possession 
of a pouch formed by folds of skin round the neck and throat, resembling that 
which has already been mentioned as occurring in the orang. Moreover, the chin 
is better developed than in all the other gibbons. 
Duvaucel’s is one of the earliest authentic accounts of the siamane: 
Mode of Life. . . . 
that we possess. Writing from the neighbourhood of Benculen 
in Sumatra, he states that “this species is very common in our forests, and 
I have had frequent opportunities of observing it, as well in its wild state as in 
bondage. The siamangs generally assemble in numerous troops, conducted, it is said, 
by a chief, whom the Malays believe to be invulnerable, probably because he is more 
agile, powerful, and difficult to reach than the rest. Thus united, they salute the rising 
and setting sun with the most terrific cries, which may be heard at several miles’ 
distance; and which, when near, deafen, when they do not frighten. This is the 
morning-call to the mountain Malays, but to the inhabitants of the towns it is a 
