the rind is cracked, and then tear it off with the fingers of the two
hands. In a wild state they break open hard fruits with stones. Other
monkeys open mussel-shells with the two thumbs. With their fingers they
pull out thorns and burs, and hunt for each other s parasites. They
roll down stones, or throw them at their enemies: nevertheless, they
are clumsy in these various actions, and, as I have myself seen, are
quite unable to throw a stone with precision.
It seems to me far from true that because objects are grasped
clumsily by monkeys, a much less specialised organ of prehension
would have served them (70. Quarterly Review, April 1869, p. 392.)
equally well with their present hands. On the contrary, I see no reason
to doubt that more perfectly constructed hands would have been an
advantage to them, provided that they were not thus rendered less
fitted for climbing trees. We may suspect that a hand as perfect as
that of man would have been disadvantageous for climbing; for the most
arboreal monkeys in the world, namely, Ateles in America, Colobus in
Africa, and Hylobates in Asia, are either thumbless, or their toes
partially cohere, so that their limbs are converted into mere grasping
hooks. (71. In Hylobates syndactylus, as the name expresses, two of the
toes regularly cohere; and this, as Mr. Blyth informs me, is
occasionally the case with the toes of H. agilis, lar, and leuciscus.
Colobus is strictly arboreal and extraordinarily active (Brehm,
Thierleben, B. i. s. 50), but whether a better climber than the
species of the allied genera, I do not know. It deserves notice that
the feet of the sloths, the most arboreal animals in the world, are
wonderfully hook-like.
As soon as some ancient member in the great series of the Primates came
to be less arboreal, owing to a change in its manner of procuring
subsistence, or to some change in the surrounding conditions, its
habitual manner of progression would have been modified: and thus it
would have been rendered more strictly quadrupedal or bipedal. Baboons
frequent hilly and rocky districts, and only from necessity climb high
trees (72. Brehm, Thierleben, B. i. s. 80.); and they have acquired
almost the gait of a dog. Man alone has become a biped; and we can, I
think, partly see how he has come to assume his erect attitude, which
forms one of his most conspicuous characters. Man could not have
attained his present dominant position in the world without the use of
his hands, which are so admirably adapted to act in obedience to his
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