Living Primates 69Some Old World monkeys are known for their un-
usual coloring, such as mandrills (pictured on page 62)
with their brightly colored faces and genitals. Others, like
proboscis monkeys, have long droopy noses. They all pos-
sess a 2-1-2-3 dental formula (two, rather than three, pre-
molars on each side of each jaw) and tails that are never
prehensile. They may be either arboreal or terrestrial, us-
ing a quadrupedal pattern of locomotion on the ground
or in the trees in a palms-down position. Their body plan
is narrow with hind limbs and forelimbs of equal length,
a reduced clavicle (collar bone), and relatively fixed and
sturdy shoulder, elbow, and wrist joints.
The arboreal species include the colubus guereza
monkey—a species known to have been hunted by chim-
panzees. Some are equally at home on the ground and in
the trees, such as the macaques, of which some nineteen
species range from tropical Africa and Asia to Gibraltar
on the southern coast of Spain to Japan. At the northern-
most portions of their range, these primates are living in
temperate rather than strictly tropical environments.
Baboons, a kind of Old World monkey, have been of
particular interest to paleoanthropologists because they
live in environments similar to those in which humans
may have originated. These baboons have abandoned
trees (except for sleeping and refuge) and are largely ter-
restrial, living in the savannahs, deserts, and highlands of
Africa. Somewhat dog-faced, they have long muzzles and
a fierce look and eat a diet of leaves, seeds, insects, lizards,
and small mammals. They live in large, well-organized
troops comprised of related females and adult males that
have transferred out of other troops.
Other Old World species also have much to tell us.
For example, over the past several decades primatologistsside of each jaw). This is not as much a functional distinc-
tion as it is a difference in evolutionary path. The common
ancestor of Old World anthropoids and New World an-
thropoids possessed this 2-1-3-3 dental pattern. In the New
World this pattern remained, while in Old World species a
molar was lost.
Like Old World monkeys, New World monkeys have
long tails. All members of one group, the family Atelidae,
possess prehensile or grasping tails that they use as a fifth
limb. The naked skin on the under side of their tail resem-
bles the sensitive skin found at the tips of our fingers and
is even covered with whorls like fingerprints.
Platyrrhines walk on all fours with their palms down
and scamper along tree branches in search of fruit,
which they eat sitting upright. Although New World
monkeys spend much of their time in the trees, they
rarely hang suspended below the branches or swing
from limb to limb by their arms and have not developed
the extremely long forelimbs and broad shoulders char-
acteristic of the apes.Old World Monkeys
Old World or catarrhine (from the Greek for “sharp-
nosed”) primates are divided from the apes at the su-
perfamily taxonomic level. They resemble New World
monkeys in their basic body plan, but their noses are dis-
tinctive, with closely spaced, downward-pointing nostrils.
Divided into two subfamilies, the Cercopithecinae and the
Colobinae, which contain eleven and ten genera, respec-
tively, Old World monkeys are very diverse and occupy a
broader range of habitats compared to New World mon-
key species, which occupy only tropical forests.© dbimages/Alamy©^
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While all Old World monkeys share cer-
tain features like a narrow body plan, a
non-prehensile tail, and a 2-1-2-3 dental
formula, some unusual specializations
are also seen. The proboscis monkey,
found in the mangrove swamps of Bor-
neo, is known for its unusual protruding
nose, which provides a chamber for extra
resonance for its vocalizations. When a
monkey is alarmed, the nose fills with
blood so that the resonating chamber
becomes even more enlarged.