A Book of Natural History | Page 9

or in an open field,
balance themselves very prettily by raising their hands over their head
and slightly bending the arm at the wrist and elbow, and then run
tolerably fast, rocking from side to side; and, if urged to greater speed,
they let fall their hands to the ground, and assist themselves forward,
rather jumping than running, still keeping the body, however, nearly
erect."
Somewhat different evidence, however, is given by Dr. Winslow
Lewis:
"Their only manner of walking was on their posterior or inferior
extremities, the others being raised upward to preserve their
equilibrium, as rope-dancers are assisted by long poles at fairs. Their
progression was not by placing one foot before the other, but by
simultaneously using both, as in jumping." Dr. Salomon Müller also

states that the Gibbons progress upon the ground by short series of
tottering jumps, effected only by the hind limbs, the body being held
altogether upright.
But Mr. Martin, who also speaks from direct observation, says of the
Gibbons generally:
"Pre-eminently qualified for arboreal habits, and displaying among the
branches amazing activity, the Gibbons are not so awkward or
embarrassed on a level surface as might be imagined. They walk erect
with a waddling or unsteady gait, but at a quick pace, the equilibrium
of the body requiring to be kept up, either by touching the ground with
the knuckles, first on one side then on the other, or by uplifting the
arms so as to poise it. As with the Chimpanzee, the whole of the narrow,
long sole of the foot is placed upon the ground at once, and raised at
once, without any elasticity of step."
After this mass of concurrent and independent testimony, it cannot
reasonably be doubted that the Gibbons commonly and habitually
assume the erect attitude.
But level ground is not the place where these animals can display their
very remarkable and peculiar locomotive powers, and that prodigious
activity which almost tempts one to rank them among flying, rather
than among ordinary climbing mammals.
Mr. Martin has given so excellent and graphic an account of the
movements of a Hylobates agilis, living in the Zoölogical Gardens, in
1840, that I will quote it in full:
"It is almost impossible to convey in words an idea of the quickness
and graceful address of her movements: they may indeed be termed
aërial, as she seems merely to touch in her progress the branches among
which she exhibits her evolutions. In these feats her hands and arms are
the sole organs of locomotion, her body, hanging as if suspended by a
rope, sustained by one hand (the right, for example), she launches
herself, by an energetic movement, to a distant branch, which she
catches with the left hand; but her hold is less than momentary; the

impulse for the next launch is acquired; the branch then aimed at is
attained by the right hand again, and quitted instantaneously, and so on,
in alternate succession. In this manner spaces of twelve and eighteen
feet are cleared, with the greatest ease and uninterruptedly, for hours
together, without the slightest appearance of fatigue being manifested;
and it is evident that, if more space could be allowed, distances very
greatly exceeding eighteen feet would be as easily cleared; so that
Duvaucel's assertion that he has seen these animals launch themselves
from one branch to another, forty feet asunder, startling as it is, may be
well credited. Sometimes, on seizing a branch in her progress, she will
throw herself, by the power of one arm only, completely round it,
making a revolution with such rapidity as almost to deceive the eye,
and continue her progress with undiminished velocity. It is singular to
observe how suddenly this Gibbon can stop, when the impetus giving
by the rapidity and distance of her swinging leaps would seem to
require a gradual abatement of her movements. In the very midst of her
flight a branch is seized, the body raised, and she is seen, as if by magic,
quietly seated on it, grasping it with her feet. As suddenly she again
throws herself into action.
"The following facts will convey some notion of her dexterity and
quickness. A live bird was let loose in her apartment; she marked its
flight, made a long swing to a distant branch, caught the bird with one
hand in her passage, and attained the branch with her other hand, her
aim, both at the bird and at the branch, being as successful as if one
object only had engaged her attention. It may be added that she
instantly bit off the head of the bird, picked its feathers, and then threw
it down without attempting to eat it.
"On another occasion this animal swung herself from a perch, across a
passage at least twelve feet