MONKEY,
generally, any one of the higher primates other than humans.
More specifically, the term monkey is restricted
to the species that in the Americas constitute the families Cebidae
(CAPUCHIN MONKEY; HOWLER MONKEY; SPIDER MONKEY,) and Callitrichidae
( MARMOSET,); and in the Old World constitute the family
Cercopithecidae (BABOON; LANGUR; MACAQUE,).
The Cebidae belong to the superfamily Ceboidea, suborder Anthropoidea.
They are characterized by 36 teeth and a broad septum between the
nostrils. The tail is often prehensile. All monkeys in this family
are arboreal and feed primarily on fruits and insects. Callitrichidae,
superfamily Ceboidea, have 32 teeth and never have a prehensile
tail. Marmosets are the smallest of all monkeys and are more primitive
than the Cebidae. Their fingers end in claws instead of nails; their
scent-marking behavior is like that of the LEMUR, as is the lack
of a strong bond between the female and her young.
The family Cercopithecidae is characterized by 32 teeth and
a nonprehensile tail, if present, and by a narrow septum between
the nostrils. Naked callous patches are on the buttocks. These animals
are not exclusively arboreal, and some—such as the baboon—spend
most of their life on the ground.
All monkeys have eyes set at the front of the head, giving
them binocular vision and the ability to judge distance and depth.
Their well-developed color vision also increases their ability to
pick out detail through the leaves of trees. For the monkeys that
adapted to life on the ground, the characteristics developed from arboreal
life serve them well: manual dexterity, keen vision, and an ability
to learn quickly from experience.