Modern Primates and Primate
A Survey of Living Primates:
Anthropoids (Monkeys, Apes, and
• The anthropoid (―humanlike‖) primates include monkeys, apes,
• Although there is much variation among anthropoids, there are
certain features that, when taken together, distinguish them as
a group from prosimians.
1. Generally larger body size
2. Larger brain (in absolute terms and relative to body weight)
3. Reduced reliance on the sense of smell, as indicated by
absence of rhinarium and other structures.
4. Increased reliance on vision, with forward-facing eyes placed at
front of face.
5. Greater degree of color vision.
6. Back if eye socket formed by a bony plate.
1. Blood supply to brain different from that of
2. Fusion of the 2 sides of the mandible at the
midline to form one bone (in prosimians and
tarsiers they are joined by fibrous tissue).
3. Less specialized dentition, as seen in absence
of the dental comb and some other features.
4. Difference with regard to female internal
5. Longer gestation and maturation periods.
6. More mutual grooming.
• Suborder Anthropoidea is further divided into
– Platyrrhini (NWM) “flat-nosed”
• Platyrrhini means “flat nose” and the noses of the
Central and South American monkeys have widely
spaced nostrils separated by a broad septum.
– Catarrhini (OWM) monkeys, apes, and humans
• If you compare this with a typical OW catarrhine nose
(“nostrils close together and facing downward”) you
will see that they are comma shaped and close
Whitehead et al. 2005
Which one is Catarrhini (OWM)
and Platyrrhini (NWM)
• NW and OW primates have different dental formulas, that is,
the number of each type of tooth in each quadrant of the mouth.
• OW have 2 incisors, 1 canine, 2 premolers (bicuspids), and 3
• It is written as 220.127.116.11 2 =32
• Some NW anthropoids have 4 extra premolars:
• 18.104.22.168 2 =36
• Other NW anthropoids have 4 fewer molars
• 22.214.171.124 2 =32
• Moreover, because NW monkeys are almost
entirely arboreal, they have evolved long limbs,
an some have clawlike nails.
– Several species also have a prehensile tail giving
them 5 grasping limbs
– NO OW monkey has this adaptation
• Finally, two groups of platyrrhines, the
marmosets and tamarins, normally give birth
Note the prehensile tail
• The OW primates are divided into two
• The monkeys of Europe (now limited to
Gibraltar), Africa, and Asia make up superfamily
– All OWM
• Apes and humans are in the superfamily
Hominoidea, which are then divided into three
The Superfamily Hominoida
• Contains the larger, tailless primates.
• The hominoids—apes and humans—are generally
larger that the monkeys and have larger brains, both
relatively and absolutely.
• Their brains also have neocortexes, meaning that the
hominoids are more intelligent as I have already
• Finally, a series of traits make the hominoids good
suspensor climbers and hangers.
• The traits behind this ability are a flexable shoulder
joint, a shoulder blade that is farther back than in
monkeys, and a stronger color bone (clavicle) for
• Includes the gibbons and siamangs of
Southeast Asia and Malaysia.
• There are 14 gibbon species and the closely
related siamang are today found in the
southeastern tropical areas of Asia.
• These animals are the smallest of the apes,
with long, slender body weighing 13 pounds in
the gibbon and 25 pounds in the siamang.
• The most distinctive structural feature of
gibbons and siamamgs is related to an
adaptation to brachiation.
• Sometimes referred to as the “lesser apes” they are
noted for their brachiating mode of locomotion
• They have extremely long arms, long permanently
curved fingers, short thumbs, and powerful shoulder
• This highly specialized locomotor adaptation may be
related to feeding behavior while hanging beneath
• The diet of both species is composed mainly of fruit.
• However, both (especially the siamang) eat a variety
of leaves, insects and flowers.
• They also have unusual social organization for
• Male and female hylobatids form monogamous pair,
though not necessarily a permanent one.
Grey Gibbon (Hylobates muelleri)
Siamangs (Hylobates syndactylus)
Pongidae, (great apes)
• There are 4 species within the family
– Orangutans (Pan pygmaeus) are represented by
two subspecies found today only in heavily forested
areas on the Indonesian islands of Borneo and
– As a result of human predation, they are an
– Orangutans are slow cautious climbers whose
locomotor behavior can best be described as “four-
handed,” referring to the tendency to use all your
limbs for grasping and support.
– They are mostly arboreal, however, they do
sometimes travel quadrupeadally on the ground.
– Pronounced sexual dimorphism (males 200 lbs;
females 100 lbs).
– In the wild they lead solitary lives, although adult
females are usually accompanied by one or two
– They are primarily frugivorous, but bark, leaves,
insects, and meant (on rare occasions) may also be
Orangutan (Pongo pygmaeus)
• Gorillas (Gorilla gorilla) are the largest of all living
– They are limited to forested areas of western and eastern
– Generally, there are three recognized subspecies:
– Western lowland gorilla
– Eastern lowland gorilla
– Mountain gorilla
• However, molecular data suggests that only one of
these, the western lowland gorilla is perhaps
sufficiently genetically distinct to warrant a separate
• The western lowland gorilla is among the
most numerous with perhaps a population size
– Systematic studies of the free-ranging WLG did not
begin until the mid-1980s; thus knowledge about
social structure and behaviors is still in its infancy.
– In general, it appears that their social structure is
simi8alr to that of mountain gorillas, but groups are
smaller and somewhat less cohesive.
• The eastern lowland gorilla is found near the
boarder of the DRC and numbers about 12,000.
• The mountain gorilla probably have never
been numerous and number about 600
– Live in groups consisting of 1 (or sometimes 2)
large silverback males, a variable number of adult
females, and their offspring.
– Silverback refers to adult males with white hair
across the saddle of their back (12-13 years)
– Typically, but not always, both males and females
leave their natal group as young adults.
– Females join other groups while males may live
alone for a while, or they may join an all male group
before eventually forming their own group.
• Gorillas exhibit marked sexual dimorphism
with males (400 lbs) weighing twice as much as
females (100-200 lbs).
– As a result of their weight, gorillas (especially
males) are primarly terrestrial and adopt a
semiquadrupedal (knuckle-walking) posture on the
– All gorillas are almist exclusively vegetarian.
– MT gorillas concentrate primarily on leaves, pith,
– WLG eat the same foods but also eat considerably
– Not the myth of the killer ape.
Right: Western Lowland Gorilla
Chimpanzee (Pan troglodytes)
• Chimps are probably the best known of the all the
• Chimp are found in equatorial Africa from the Atlantic
Ocean in the west to Lake Tanganyika in the east.
• Chimps are in many ways structurally similar to
gorillas, with corresponding limb proportions and
• This similarity is due to commonalities in locomotion
when on the ground (quadruped knuckle walking).
• However, ecological adaptation of chimps and gorillas
differ, with chimps spending more time in the trees.
• Moreover, while gorillas are typically placid and quiet,
chimps are highly excitable, active, and noisy.
• Chimps are smaller than orangutans and
gorillas, but they do exhibit sexual dimorphism,
just not as much as orangutans and gorillas.
Males just over 100 lbs and females around 80
• In addition to knuckle walking, chimps (in
particular young) may brachiate while in the
• On the ground, they frequently walk bipedally
for short distances when carrying food or other
• They eat a variety of food items, including fruit,
leaves, insects, nuts, birds’ eggs, berries
caterpillars, and small mammals.
• They live in large fluid communities of as many as 50
individuals or more.
• At the core of a chimp community is a group of
– While this relationship is not always peaceful or stable, these
males use each other to defend their territory.
• Adult females tend of forage alone or in the company
of their offspring.
• Their social behavior is complex and individuals form
lifelong attachments with friends and relatives.
• The bond between mother and child is strong lasting
their whole lives
• Chimps live to their mid-30s early 40s
themselves into complex
social structures, requiring
Bonobos (Pan paniscus)
• Are found only in an area south of the Zaire River in
• They are among the least studied of the great apes.
• There are no accurate counts but it is believed that
their numbers are around 10,000 to 20,000
• They are sometimes called ―pygmy chimpanzee‖
because of their strong resemblance but smaller size.
• However, this title is a misnomer because in fact
bonobos exhibit several anatomical and behavioral
differences from chimps.
– They have a more linear body build
– Longer legs relative to arms
– A relatively smaller head
– A darker face from birth
– Tuffs of hair on the side of the face.
• They are more arboreal than chimps and
appear to be less excitable and aggressive.
• Physical violence both within and between
groups are uncommon.
• These groups are centered around female
bonding not male like chimps.
• Bonobo sexuality is different than in chimps.