Download Chapter 5 The Primates Overview Humans are animals, chordates

Chapter 5
The Primates
Overview
•
Humans are animals, chordates, and vertebrates. We share certain characteristics, such as a more developed nervous
system, with other creatures in these categories.
o
Humans are mammals which means we rely a great deal on a reproductive strategy of few births and extensive
parental care.
o
Humans belong to a specific order of mammals known as primates.
o
There is a great deal of biological and behavioral variation among the living primates.
o
Humans are mammals
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It is first necessary to understand the basic characteristics of these larger taxonomic groups
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Kingdom is the most inclusive taxonomic category. All living organisms can be places into one of five kingdoms:
plants, animals, fungi, nucleated single-celled organisms, and bacteria. Humans belong to the animal kingdom

Humans belong to the phylum Chordata (animals with a spinal chord, called a notochord).

Humans belong to the subphylum Vertebrata (the vertebrates, animals with backbones).

One characteristic of vertebrates is bilateral symmetry -- left and right body sides are mirror images

See Table 5.1 for the complete list of human classification
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The first primitive mammals evolved from early reptiles about 200 mya and it is for this reason that a comparison of
mammals with reptiles is useful.
Characteristics of Mammals 1
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Reproduction
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Mammals are often identified as animals that give birth to live offspring (other vertebrates lay eggs).

There are exceptions as some fish lay eggs and some mammals lay eggs (platypus)

Others birth immature offspring and nurture in poaches (marsupials)
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Placental mammals

Placental mammals are those with placenta, an organ that develops inside the female during pregnancy.

The placenta links the mother and fetus and transports food, oxygen and antibodies and filters waste.
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Placental mammals have a much greater chance for survival.

Female mammary glands are a main feature of mammals that provide food and immunities in the mother’s
milk.
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Parental care
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Mammals exhibit patterns of prenatal (conception to birth) and postnatal (after birth) parental care.

Species vary in terms of balance between number of offspring and degree of parental care.

Mammals have relatively few offspring, but provide much more parental care. This has advantages and
disadvantages.

Temperature regulation
o
Modern mammals are homeotherms (capable of maintaining a constant body temperature under most
circumstances).
o
They are covered with fur or hair that insulates the body preventing heat loss in cold weather and reducing
overheating in hot weather.
o
Mammals also maintain a constant body temperature by ingesting large quantities of food, converting it to
energy in the form of heat.
o
Mammals are capable of exploiting a large number of environments.
o
Humans have gone beyond basic temperature-regulating abilities through various technologies
Characteristics of Mammals 2
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Teeth
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Mammals have different types of teeth in their jaws.

They are heterodontic.

They usually have two sets of teeth during their lives—deciduous (‘baby’) teeth and a set of permanent teeth.

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Mammals have four different types of teeth: incisors (chisel-shaped front teeth for cutting, slicing, and
gnawing), canines (teeth behind the incisors for puncturing and defense), premolars (back teeth used for
crushing and grinding food), and molars (teeth furthest back, also for crushing and grinding).
One way to describe the heterodont pattern of primates is by the dental formula.

This is the number of each kind of teeth on the upper mouth (one side) with the number of each kind of teeth
on the lower mouth (one side)

Kinds of teeth: incisors, canines, premolars, and molars. Dental formula is largely consistent with that of
other mammals

Not all primates have the human dental formula

Notice the gap for the New World monkeys? That is called a diastema and is so the upper canine can fit in
many primates).
Characteristics of Mammals 3
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Diet and teeth
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The nature of mammalian diet and teeth relates to their warm-bloodedness.
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Mammals need more food than reptiles, and their teeth allow them to utilize a wider range of food and process it
more productively.
1. Lack of dietary specialization, means most are omnivorous
2. Terms: Omnivore (means ‘all eating’); carnivores (including insectivores); herbivores (which include
frugivores (fruit-eaters) and foliovores (leaf-eaters).
3. Teeth are generalized because primates are omnivorous
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Skeletal structure
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Mammals and reptiles both share the basic skeletal structure of all vertebrates.
o
There are some differences, especially in movement.

In reptiles, the four limbs come out from the side of the body for support and movement.

In four-legged mammals, the limbs slope downward from the shoulders and hips, allowing for more efficient
and quicker movement. The weight of the body is also supported better.

Humans differ from the pattern of many mammals by having only two limbs for movement (bipedal).
Characteristics of Mammals 4
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Behavior
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Brains of all vertebrates have similar structures but differ in size, relative
proportions, and function
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All vertebrates have a hindbrain, midbrain, and forebrain.

The hindbrain is associated with hearing, balance, reflexive behavior,
and control of the autonomous functions of the body (breathing)
Diagram of mammalian brain

The midbrain is associated with vision
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The forebrain is associated with chemical sensing; it is enlarged in mammals and responsible for processing
sensory information and coordination. It contains the cerebrum, the outermost layer of brain cells—associated
with memory, learning, and intelligence.
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Overall brain functions include basic body maintenance, processing and responding to information.
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Mammals rely increasingly on learning. Behaviors are less instinctual and rigid.
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Learning becomes more important in responding to stimuli, allowing mammals to develop new responses to
different situations.
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Behavioral flexibility in mammals is tied to reproductive patterns; reliance on parental care increases intelligence.
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Major mammalian characteristics are interrelated. Reproductive behaviors are associated with learning intelligence,
and social behaviors.
Characteristics of Primates 1
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Primates are not identified by a single feature, but rather, a set of features retained from ancestors.
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Primates include humans, the apes, the monkeys, tarsiers, lorises and lemurs.
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Over time this group acquired addition traits that separate them from other mammals
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General characteristics of an arboreal environment
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The primates are an order of mammals that have a complex of characteristics related to an initial adaptation to life
in the trees.
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Arboreal (tree-living) environments present different challenges from terrestrial (ground-living) ones.
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Arboreal living is three-dimensional, terrestrial is a two-dimensional environment. Depth and distance
perception is vital in the trees.
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Primates are capable of extensive rapid movement through the trees.
Skeleton
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Grasping hands
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Hands and feet with a high level of prehensibility (ability to grasp); not all primates have highly efficient
opposable thumbs
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Tactile pads and nails on fingers and toes
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Hands are adapted for precision grip and well as power grip and the retention of 5 digits on hands and feet.
o
•
Characteristics of Primates 2
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Skeleton (continued)
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Grasping hands (continued)
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Primate success in the trees are due to two major characteristics: their ability to use hands and feet to grasp
branches and the ability to perceive distance and depth

Another feature of primate hands is their expanded tactile pads (the ball of your thumb) and not claws

Not all modern primates have kept the original adaptations of the first primates. Humans can still use their
hands to grasp objects but cannot do so with their feet.
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Our inherited ability to grasp has been put to use in other ways (holding tools, weapons, food, and
children).
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Grasping hands of humans and monkeys are homologous (due to common descent).
o
Generalized skeleton
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Primate’s basic skeletal structure is generalized (generalized structures are adapted to a wide range of
conditions) rather than specialized structures (adapted to a narrow range of conditions in specific ways)
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Arms and legs of primates follow a basic vertebrate pattern: each limb consists of an upper bone and two
lower bones. This allows flexibility at the elbow or knee.
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Climbing or jumping in a tree requires flexibility. This is obtained by the retention of a generalized skeletal
structure.
Primate Characteristics 3
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Vision
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Nocturnal (night-active) primates are more likely to rely more on the sense of smell (olfactory sense) than diurnal
(day-active) primates, which rely more on the sense of vision.
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Color vision is a characteristic of all diurnal primates. The nocturnal owl monkey only sees monochromatically.
In between these extremes, color vision is variable.
o
Depth perception (stereoscopic vision) allows primates to see 3-D. Several mechanisms help this to happen:
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Binocular vision (two eyes in front that have overlapping visual fields)
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Visual information is transmitted to both sides of the brain (60 opposite side of brain-40% on same side).
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3-D images are produced by specialized structures in the brain.
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Decreased olfaction (see Figure 6-4 and look for position of the eye sockets and the postorbital bar)
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Expansion and increased complexity of the brain
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Primates have the highest brain to body ratio
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The expansions are especially in the areas of the neocortex (where different sensory modalities are processed)
Characteristics of Primates 4
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The brain and behavior
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Primates have expanded on the basic mammalian brain pattern.
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Their brains are even larger relative to body size and they have larger visual and smaller areas for smell.
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Their brains are also more complex.
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Learning
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Those areas associated with body control and coordination are proportionately larger. Hand-eye coordination
is crucial in arboreal living.
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Primate brains also have larger proportions associated with learning and intelligence.

Primate behavior is reflected in the greater size and complexity of their brains.
It is often difficult to assign specific behaviors to a given species of primate due to the increased emphasis on learning
and flexibility.
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A greater proportion of primate life is spent growing up, both biologically and socially.
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The need to learn means more time learning.

Greater amounts of parental attention and care are required
•
The basic primate learning pattern provides a means by which new behavior is passed on from one generation to
the next.
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We call this culture in humans.
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In nonhuman primates this is referred to as protoculture. YouTube click (7:30 minutes)
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Characteristics of Primates 5
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The brain and behavior (continued)
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An example of learned behavior in primates
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Primate studies provide may good examples of the introduction of new behaviors to a group by one or more
individuals.
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Japanese macaque studies in the 1950’s on the island of Koshima provide a good example.

In 1953, this involved a female named Imo and washing sweet potatoes in a stream before eating them.
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A 1956 study followed her teaching how to clean wheat grains by floating them in water.
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Studies of cultural transmission among Japanese macaques shows the importance of learning in primates.
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Another example are the many behaviors of orangutans who are living in sanctuaries. They fish with spears,
try to copy human behaviors and have even stolen fishing boats from locals.
o
Chimpanzees are the most famous group to most people. Beginning with the documentation by Jane Goodall, we
know chimpanzees use many tools.
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The three most famous are Jane Goodall (chimpanzees), Dian Fossey (mountain gorillas), and Biruté Galdikas
(orangutans) -- all protégés of Louis Leakey (famous paleoanthropologist).
Primate Diversity 1
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Primates are quite a variable group of mammals, both biologically and behaviorally
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Given that not all primates have all the traits associated with the Primate Order, there have been taxonomic
debates over which species to include.
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One debate was going on when I entered anthropology. What to do with the tree shrew
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Is it a primate (order Primates) or an insectivore (order Insectivora)?
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It has also been proposed to place the tree-shrews in the separate order Scandentia
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The problem with placing tree-shrews into the order Primates is that tree-shrews and primates do not share
any derived traits
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Some researchers still argue that they are the most primitive of the primates, however.
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Most place in Scandentia.
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Primate-like traits of tree shrews:
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Note the position of the eyes are more forward
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They have the same generalized mammalian skeleton.
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Placental and omnivorous (meaning will eat many things)
•
But:
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All claws and hands not prehensile
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Strong sense of smell as well as sense of vision.
Primate Diversity 2
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Primate taxonomy (3 versions)
1. We start by discussing the traditional taxonomy: The issue was over where to place the tarsiers and the new
taxonomy differs there.
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The two major subgroups of living primates are the suborder Prosimii and suborder Anthropoidea

These are the official Latin terms

More casually, we use prosimians and anthropoids.

The prosimians grouped together the lemurs, lorises and tarsiers.
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2.
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
o
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The anthropoids consisted of the New World monkeys (NWM), Old World monkeys (OWM), apes and
humans.
The most widely used (newer) taxonomy places the tarsiers with the group of “anthropoids” and renames the
suborders:
The new suborder that contains the lemurs and lorises is called Strepsirrhini (meaning turning nose; sometimes
also called wet nose)
All other primates are grouped together into the suborder Haplorrhini (meaning simple nosed, sometimes also
called downward nose or dry nose)
The very newest taxonomy changes the grouping at the infraorder level rather than the order.
It merges the platyrrhines and the catarrhines into a newly named infraorder “Simiiformes:
A new level of taxonomic classification is inserted (the parvorder) and this is where these two taxonomic groups
are distinguished.
Traditional Taxonomy (Not pictured)
Newer Taxonomy (Not pictured)
Newest Taxonomy (Not pictured)
Primate Diversity 3
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This survey of the primates is extremely general. Remember there are about 230 living species.
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The intent, then, is to give a glimpse concerning the diversity of the order Primates.

As we proceed, try to note where the authors shift between the 2 taxonomic systems
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Strepsirhines (Lemurs and lorises)

They often lack one or more of the general characteristics of primates like color vision, and some have a single
claw on each hand or foot.
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Lemurs and lorises retain more of the primitive primate traits:
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Includes a stronger reliance on olfaction.
• One example of this reliance on olfaction is the presence of a rhinarium
• Another example is that there is a more lateral placement of the eyes

Another primitive trait is a shorter gestation and maturation

They also possess dental specialization called the dental comb. This dental comb is used in grooming and
feeding

They have a claw on the second toe.

Their faces are less mobile (‘poker-faced’)

Tapetum lucidum or a layer of cells in the eyes of some animals that increases the reflection of light on the
retina.
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Postorbital bar is not closed.
Primate Diversity 4
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Strepsirhines (Lemurs and lorises) (continued)
o
Profile of the lemurs
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Geography/habitat

Lemurs are found only on the island of Madagascar and nearby islands off the east coast of Africa; extinct
elsewhere in the world

Lemurs diversified into ecological niches without competition and number about 60 species today. Some
are arboreal, others (including the ring-tailed lemur) are terrestrial.
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Some arboreal species are quadrupeds and others are vertical clingers and leapers (sifakas and indris)

Physical traits

Lemurs range in size from the small mouse lemur, with a body length of only 5 inches, to the indri, with a
body length of 2 to 3 feet.

Larger lemurs are diurnal and are comparatively omnivorous; The smaller lemurs are nocturnal and
insectivorous.
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Social behaviors

Some are socially gregarious (ring-tailed lemurs and sifakas) live in groups of 10-25 animals
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Others (the indris) live in family units of mated pairs and offspring
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Several nocturnal forms are mostly solitary
Relethford Chapter 5 Page 5
Primate Diversity 5
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Strepsirhines (Lemurs and lorises) (continued)
o
Profile of the lorises
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Lorises were able to survive in mainland areas of Africa by adopting to nocturnal activity.

Where are they?

There are at least eight loris species found in tropical forest and woodland habitats of India, Sri Lanka,
Southeast Asia, and Africa.

An additional 6-9 species of galagos (bush babies) are found in the forested/woodland areas of subSaharan Africa

Locomotion is by slow, cautious climbing of quadrapedialism for the lorises, but the galagos are agile vertical
clingers and leapers.
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Some lorises and galagos are almost completely insectivorous, Others supplement the diet with fruit, leaves,
gums and slugs.
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Foraging is mostly solitary (females leave infants behind) but ranges may overlap.
o
Haplorhines (Tarsiers, NWM, OWM, apes and humans)
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There are two suborders (using Groves newest taxonomy): the Tarsiformes and the Simiiformes)

It is important to note that while Simiiformes is the technical term, common use term is anthropoids (tradition
and convenience) and is used to refer to monkeys, apes and humans.
Primate Diversity 6
o
Haplorhines (continued)
o
Profile of tarsiers

There are five recognized tarsier species all in island areas in Southeast Asia.

Tarsiers are nocturnal insectivores that leap onto prey from lower branches and shrubs.

They appear to form stable pair bonds, and the basic social unit is a mated pair and their young offspring.

Tarsiers have only two, rather than four, incisors in their lower jaw. Their dental formula is 2.1.3.3/1.1.3.3
o
Tarsiers are a blend of characteristics.

Prosimian traits include: nocturnal activity, small body size, unfused mandible (lower jaw), relatively large
ears, and a grooming claw.

Anthropoid traits include: lack of naked rhinarium (dry nosed), enclosed bony eye sockets,
chromosomal/DNA arrangements and internal arrangements match those of other anthropoids. The monthly
sexual swellings of female tarsiers are also similar to those in anthropoids.

Unique traits include: large eyes - each is larger than their brain, and they are immobile in their sockets. neck
- capable of rotation up to 180 degrees. (Tarsiers are primarily insectivores and this eye/neck combination
may be helpful in catching their prey at night.)
Source: PrimatePage (2004).Tarsier. Retrieved from
http://www.geocities.com/RainForest/Canopy/3220/IOtarsiiformes.html
Source: Ijsselstein. (2004, April 24). The Philippine tarsier. Retrieved from http://www.bohol.ph/article15.html
Primate Diversity 7
o
Haplorhines (continued)
o
Simiiformes “Anthropoids”: monkeys, apes & humans
o
General statements, but here are a few points to keep in mind:

Monkeys and apes are often confused in the popular imagination. Monkeys have tails. Apes and humans do
not.

Monkeys generally have smaller brains relative to body size that apes or humans.

Monkeys are quadrupedal (all four legs are of equal size and make contact with the ground). Apes have
relatively longer arms than legs; humans have longer legs than arms.

Features of the anthropoids
o
Generally larger body size and a larger brain
o
Reduced reliance on sense of smell and an increased reliance on vision.
o
Greater degree of color vision with the back of eye socket formed by a bony plate
o
Blood supply to brain different from prosimians
Relethford Chapter 5 Page 6
o
o
o
o
Fusion of two sides of the mandible to form one bone.
Less-specialized dentition
Different female internal reproductive anatomy and longer gestation and maturation periods
Increased parental care and more mutual grooming
Primate Diversity 8
o
Haplorhines (continued)
o
Profile of the New World Monkeys (NWM) – Platyrrhines (flat-nosed)
o
The New World moneys are the only form of anthropoids found native to the New World (Mexico and Central
and South America) and there are about 70 species
o
They share many similarities to Old World monkeys, but separate lines of evolution are reflected in several
important differences

They exhibit a wide range of size, diet and ecological adaptation.

Size ranges from 12 ounces (tiny tamarins and marmosets) to 20-pound howler monkey

Almost exclusively arboreal, and some species never come to the ground

Mostly found in forested region

Only the owl monkey is nocturnal, all others are diurnal
o
Traditional taxonomy is Callitrichidae and Cebidae Today it is disputed, but we will use for now

Callitrichidae are the marmosets and tamarins
o
These are the smallest
o
Claws instead of nails, which they use to climb
o
Mostly insectivores, but the marmosets also eat gums
o
Small groups of mated pair or 1 female and 2 males and their offspring (tamarins may have twins)
o
Size ranges from 12 ounces (tiny tamarins and marmosets) to 20-pound howler monkey
Primate Diversity 9
o
Haplorhines (continued)
o
Profile of the New World Monkeys (NWM) (continued)

Cebidae are all others

Range in size from squirrel monkey (12 inches) to howler (24 inches)

Varied diet with combinations of fruit, leaves with some insects

Most are quadrupedal, with a few semibrachiators (muriquis, howlers, and spider monkeys) The prehensile
tail of New World monkeys is a derived trait. The Howler monkey is an example of a New World monkey.

Socially in groups of both sexes and ages, Some are monogamous pars with subadult offspring (titis)
o
Profile of the Old World Monkeys (OWM)

Except for humans, the Old World monkeys are the most widely distributed primates and are found in subSaharan Africa, southern Asia and even Japan.

OWM are both biochemically and physically more similar to humans than are New World monkeys.

They share the same 2.1.2.3/2.1.2.3 dental formula has occupy a wide range of environments, including
tropical rain forests and savannas (open grasslands).

Most Old World monkeys are quadruped (moving on all fours) and arboreal, but some are adapted to a
terrestrial life (baboons).
Primate Diversity 10
•

Haplorhines (continued)
Profile of the Old World Monkeys (OWM) (continued)

The group Cercopithecidae are divided into two subfamilies

The cercopithecines are the more generalized of the two subfamilies, are more omnivorous, using cheek
pouches to store food

Most are found in Africa, but the macaques are in Asia, India and Japan

The species of the subfamily colobine are narrower in food preferences and mainly eat mostly leaves

Called foliovores, also called the leaf-eating monkeys

Mostly found in Africa, but the red colobus and the white colobus are found in Africa
Relethford Chapter 5 Page 7

OWM are very sexually dimorphic, especially the baboon and the patas (males as large s 80 pounds, females
about half)

In some species (especially baboons and macaques)

Females in estrus have pronounced external genitalia when in estrus

Socially (complicated, but generally):

The colobines tend to live in small groups of 1-2 adult males

Savannah baboons and macaques are in large social units

Monogamous paring is not common in OWM, but is seen in a few langurs and maybe 2 of the
guenon species
Primate Diversity 11

Haplorhines (continued)
o
Hominoids (Apes and Humans)

Apes and humans differ from monkeys in several ways:

Dental formula is 2.1.2.3 with the lower molars having 5 cusps in a Y-5 pattern

Larger body size (except for gibbons and siamangs), along with absence of a tail

Shortened trunk as well as differences in the shoulder joint

More complex behavior, along with more complex brain and enhanced cognitive abilities

Increased period of infant development and dependency.

The superfamily Hominoidea includes;

Small gibbons and siamangs in the family Hylobatidae

Some great apes in the family Pongidae (orangutans, gorillas,

New taxonomy puts other great apes (bonobos, and chimpanzees)in same tribe as humans (Hominin). At
the subtribe level (not pictured) they break out into Hominina and Panina.
Primate Diversity 12
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Haplorhines (continued)
o
Profile of gibbons and siamangs

Gibbons and siamangs are the members of the family Hylobatidae

These 12 or so species live in the southeastern tropical regions of Asia (Number is debated because of
taxonomic disagreements)

The gibbon and siamangs are the smallest of the living apes. Body size is about 13 pounds for gibbons and 25
pounds for siamangs
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They usually live 80-100 feet up in the trees.

Both are adapted for brachiation.

They can feed while suspended

They eat a variety of leaves, flowers and insects

Can travel 3 meters in one swing up to 10 meters!

Walk using bipedal locomotion if on the ground

They have a monogamous family structure (adult male, adult female and offspring).

Sometimes called ‘monogamous’ but have been seen to mate with others outside the bond.

Males are very involved in child rearing
o
They actively defend territories. The range can be up to 50 acres. Vocalizations are a part of this protection of range
Primate Diversity 13
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Haplorhines (continued)

Profile of orangutans

The word orangutan means “man of the forest” in Malay. Its most obvious physical characteristic is its
reddish brown hair. Orangutans are called the ‘red apes’.

The orangutan is a large ape found only in certain areas of Southeast Asia (Sumatra and Borneo).

Can reach 200 pounds for males, females about 100 pounds (sexually dimorphic)

Orangutans are agile climbers and hangers and are largely arboreal.

They slowly rock the tree they are on in the direction of the next and move over when they are close
together.

Bipedal on the ground
Relethford Chapter 5 Page 8
Orangutans tend to be solitary.

Their primary social group consists of mother & infant.

Males are not needed for protection.

There is little danger of predation.

Offspring may stay with mother as long as 8 years. Critical in a species that is mostly solitary to learn as
much as is possible.

They are polygamous, with the males home range overlapping a number of females’ home ranges
Small group size may reflect an environment with widely scattered food resources

o
Primate Diversity 14

Haplorhines (continued)
o
Profile of gorillas

The gorilla is the largest living primate.

They are found only in equatorial Africa.

Three subspecies are described by location:

Western lowland gorillas in west and central Africa is the most numerous (book reports 110,000, but
in 2008 found another 125,000!)
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Eastern lowland gorillas are fond in the Congo at 12,000

Mountain gorillas are found in Rwanda, the Congo, and Uganda at 600

They are predominantly terrestrial and are knuckle-walkers (walk on all fours with the weight of the arms
resting on the knuckles of the hands).

Because of their size, gorillas have few problems with predators (except for armed humans). Poaching
and encroachment by humans has caused their range to rapidly disappear The adult silverback is
dominant and can reach 400 pounds, females 200

Mountain gorillas live in small social groups of an adult male, several adult females, and their immature
offspring. Blackback males, who may be tolerated by the silverback, are likely his sons.

Western lowland gorillas are understudied, but may be socially similar to the mountain gorillas

Almost exclusively vegetarian Seen using a long stick to dig

Despite many myths concerning their desire for human flesh, they eat a diet of primarily leaves and fruit.
Gentle unless threatened.
Primate Diversity 15
o
Haplorhines (continued)

Profile of chimpanzees

Chimpanzees are probably the best known of primates.

Found in equatorial Africa, but also in laboratory settings

Anatomically similar to gorillas, but some differences as they spend more time in the trees. Younger chimps
may brachiate in the trees, but knuckle-walking is most common form of locomotion

Males may reach 150 pounds, females 100 pounds, so there is sexual dimorphism, but less than seen in
orangutans or gorillas.

Very omnivorous

Known to fish for termites or use rocks to crack nuts

Know to hunt in groups (males)

Now know can make spears to hunt bush babies

Social groups are very fluid (fission-fusion), volatile, and made of bonded males

Tend to forage alone or in small groups

Adult males are generally dominant.

Females in estrus may leave own group temporarily or permanently

The most important social behaviors revolve around mother and infant.
Primate Diversity 16

Haplorhines (continued)
o
Profile of bonobos

Bonobos are the least well known of the African apes.
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They are closely related to the chimpanzee, and were commonly considered a separate species of
chimpanzee known as “pygmy chimpanzee.”

They are slightly smaller, have a more linear body build, longer legs to arm ration, a smaller head, dark
face from birth, and tuffs of hair at side of face.

They can walk upright more easily than other apes and are more arboreal than chimpanzees
It has been suggested that the first hominoids may have been quite similar in many ways.
They are unique to a restricted rainforest region of Zaire, central Africa. There is no accurate count of
bonobos. Estimated to be between 10-20,000

They eat a leaf and plant diet; includes worms and fish

Some examples of hunting monkeys
Social structure

Seem to be less violent than chimpanzees; Franz de Waal (well-known primatologist) calls them
“hippies” for their peaceful, sex-focused behaviors

Bonobos live in large multimale / multifemale groups like chimpanzees and also practice fission-fusion
during the day and regroup at night.

The social bond is female core: Strongest social bonds exist between adult females, even though they are
not related (females leave natal group around 8 years of age).

Female-male bonds are stronger than seen in chimpanzees. Strongest social bonds exist between adult
females.

Females may have first baby at about 13 years and may carry an infant for up to 2 years after birth




What’s a Hominin?
• Name for members of tribe Hominini and refers to all great apes (orangutans, gorillas, chimpanzees, and bonobos)
and humans. See Figure 9.8 (p. 204)
o
Hominin is the term for members of the family Homininae, which includes all bipedal hominoids back to the
divergence from African great apes
o
We know (now) that chimpanzees and bonobos are more closely related to us than to other apes.
o
The term hominid (which I used for decades) to mean our direct lineage is now being used for all great apes and
human.
• The earliest hominins (so far) have been traced to the end of the Miocene, and consist of dental and cranial pieces and
demonstrate that mosaic evolution of hominin traits was the norm
o
Mosaic evolution is defined as a pattern of evolution in which the rate of evolution in one functional system varies
from that in other systems.
o
For instance, in hominin evolution, the dental system, locomotor system, and neurological system (especially the
brain) all evolved at markedly different rates
o
So what is a hominin? Defined by dental features (small canines & thick molar enamel) bipedal locomotion
(obligate), large brain size, and tool making behavior
Traditional/Revised Hominoid Classification
Traditional
Revised
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Primate Diversity 17

Haplorhines (continued)
o
Profile of humans (More details in Chapter 7)

Human beings are basically exaggerated African apes.

The closeness is poignantly pictured here

We are unique (among mammals) in our form of habitual bipedal locomotion.

We are adapted to digest a wide assortment of foods

Except for reduced canine size, human teeth are typical primate teeth.

Dependence on vision, decreased reliance on olfaction, flexible limbs and grasping hands, are rooted in our
primate past.

The neurological basis for intelligence is something we share with other primates

Defined as:

Mental capacity; ability to learn, reason, or comprehend and interpret information, facts, relationships,
and meanings.

The capacity to solve problems, whether through the application of previously acquired knowledge or
through insight.

There are many kinds of intelligence (others argue these are abilities): Linguistic intelligence, logicalmathematical intelligence, musical intelligence, spatial intelligence, bodily kinesthetic intelligence,
interpersonal intelligence, and intrapersonal intelligence

Human are completely dependent on culture. Which explains the human paradox (How can a K-selected
species like humans be so widely distributed geographically?)
Endangered Primates
•
Three reasons for the worldwide depletion of nonhuman primates
o
Habitat destruction
o
Hunting for food (bushmeat)
o
In West Africa the most serious problem is hunting to feed the growing human population.
o
Estimated that thousands of primates, are killed and sold for meat every year.
o
Primates are also killed for commercial products.
o
Live capture for export or local trade
•
Why primates make bad pets
o
They are too smart to be pets
o
They are aggressive and not domesticated
o
They are endangered; one estimate is that 4 primates die for each that is sold
o
They live a long time (some species nearly as long as humans)
o
They are social so having a single pet makes them insane (literally)
•
Like primates? Support sanctuaries
o
Here is one called Born Free Primate Sanctuary
o
Here is another called OPR Coastal Primate Sanctuary in Washington
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