its limbs.

That this animal dwelt mainly in trees in the first stage of its
existence, and possessed a powerful grasping power in its hands, we have
corroborative evidence in recent studies of child life. The human
infant, in its earliest days of life, displays a remarkable grasping
power, being able to sustain its weight with its hands for a number of
seconds, or a minute or more, at an age when its other muscles are
flabby and powerless. It appears in this to repeat a habit normal to the
ancestral infant, an instinct developed to prevent a fall from its home
among the boughs.

Yet it is doubtful if the man-ape long remained a specially arboreal
animal. The varied length of arm in the anthropoid apes was doubtless of
early origin, and in all probability man's ancestor had originally a
shorter arm than its related species. If so, this must have rendered it
less agile in trees than other forms. If we could see this ancient
creature in its arboreal home, we should probably find it more inclined
to stand erect than the other apes, walking on a lower limb, and
steadying itself by grasping an upper limb. This would be a more natural
and easy mode of progression to a short-armed animal than the crouching
attitude of the orang or the swinging motion of the gibbon, and its
effect would be to make the erect attitude to a large extent habitual
with this animal.

In short, man's ancestor may have become in considerable measure a biped
while still largely a dweller in the trees, and to that degree set its
arms free for other duties than that of locomotion. Like the other apes,
it probably often descended to the ground, where its habit of walking
erect on the boughs rendered the biped walk an easy one, or where this
habit may have been originally acquired. While this is conjectural, it
is supported by facts of organization and existing habit, and for the
reasons given it seems highly probable that the ancestor of man took to
a land residence at an early period in its history, climbing again for
food or safety, but dwelling more and more habitually on the earth's
surface. Even at this remote era it may have become essentially human in
organization, its subsequent changes being mainly in brain development,
and only to a minor extent in physical form and structure.

Fossil apes have not been found farther back than the Miocene Age of
geology. It is quite probable, however, that they may yet be found in
Eocene strata, since example