An Overview of The Primates

1
An Overview of The Primates

• Characteristics and Adaptations

2

• There are about 190 living species of primates in
  the world.
• We are not sure how many have existed during the
  orders evolutionary history of more that 55
  million years.
• Primates range from very small to quite large
• mouse lemur of Madagascar, which weighs 3 ounces
• Gigantopithecus, an extinct ape from China,
  Vietnam, and India that may have stood 12 feet
  tall and weighed half a ton.

3
Mouse lemur
Gigantopithecus
4
Primates As Mammals

• There are approximately 190 species of nonhuman
  primates
• Primates belong to
• Vertebrate class - Mammalia
• Subgroup of placental mammals.

5
Characteristics of Primates

• Fur (body hair)
• Long gestation followed by live birth
• Homeothermy, the ability to maintain a constant
  body temperature
• Increased brain size
• Capacity for learning and behavioral flexibility.

6

• Some animals live in a world dominated by sound
  (i.e. bats and dolphins) while others live in a
  world of smells (i.e. dogs).
• However, vision is the predominate sense for the
  primates.
• Most primates see in color, and all primates see
  in three dimensions.
• They have true depth perception, called
  stereoscopic vision.
• This is possible because their eyes face forward
  and see the same scene from slightly different
  angles.
• The nerves and muscles of most primates eyes are
  protected by being enclosed within a bony socket.

7
Binocular Vision in Primates
8

• Other primate senses not as acute as mammals.
• Primates lack the auditory and olfactory
  sensitivity of dogs, cats, and cattle.
• Olfactory senses
• primates, for the most past, tend to lack a snout
  and so are relatively flat-faced in profile.
• As one might guess for a group of 190 species,
  there is some variation among primates.
• Many members of one group of primates (the
  prosimians) are nocturnal and lack color vision,
  but they have better senses of smell and hearing
  than do monkeys, apes, and humans.

9
Primate Limbs

• A tendency towards erect posture.
• Hands and feet possess grasping ability.
• Features of the hands and feet
• 5 digits on hand and feet
• Opposable thumb
• partially opposable great toe
• Tactile pads enriched with sensory nerve fibers
  at the ends of digits

10
Movement

• Like most animals, primates are, with one
  exception, quadrupedal.
• Although many primates can stand of even walk on
  two legs for short periods of time, humans are
  the only habitual bipedal primates.
• Unlike most mammals, the limbs of primates are
  extremely flexible, and the hands (and in many
  cases feet) of primates have the ability to grasp
  objects.
• That is they are prehensile.
• Primates use this trait for several forms of
  locomotion.
• Some primates, called vertical clinger and
  leapers, jump from branch to branch to trunk to
  truck, using the grasping ability of all four
  limbs.

11

• The apes are supensory climbers with the ability
  to hang and climb by the arms.
• An extreme form of this mode of movement is
  brachiation, swinging arm-over-arm through the
  trees.
• When on the ground, most primates use all fours.
  
• Orangutans walk on their fists.
• African apes have a unique from of
  quadrupedalism, supporting themselves on the
  knuckles of their hands instead of the palms.

12

• Primate species may use one or more of these
  locomotor methods, depending on their anatomy and
  the situation.
• In addition, most primates are able to touch
  their thumbs to the tips of the other fingers on
  the same hand, allowing them to pick up and
  manipulate small objects.
• This is called opposability and dexterity.
• Precision grip
• Most primates have nails rather than claws on the
  tips of the fingers and toes.
• These provide support for the sensitive tactile
  sense receptors of the fingers.

13
(No Transcript)
14
Tarsier (Tarsius spectrum) Adult note the
position of the head (360º) Location Borneo
Wooly monkey (Lagothrix lagotrica)Juvenile
Female, hanging by prehensile tailLocation Rio
TapichePhotographer Roy Fontaine
15
Gibbon (Hylobates lar)
Orangutan (Pongo pygmaeus) Subadult male showing
brachiation Location San Diego Zoo
16
Primate Senses and the Brain

• Color vision is a characteristic of all diurnal
  primates, nocturnal primates lack color vision.
• Depth perception is made possible by eyes
  positioned forward on the front of the face.
• Decreased reliance on the sense of smell
  (olfaction).
• The brain has expanded in size and become
  increasingly complex.

17
Primate Maturation

• Longer periods of gestation
• Reduced numbers of offspring
• Delayed maturation
• Extension of the entire life span.

18

• Like most mammals, primates take an active role
  in the protection, nurturing, and socializing of
  their young.
• Mostly because of their large brains and because
  of the importance of learning, young primates are
  dependent upon adults and take a long time to
  mature.
• Primates, relative to size, have the longest
  period of postnatal dependence of any mammal.