Clever Monkeys
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Part 1/6
Part 2/6
Part 3/6
Part 4/6
Part 5/6
Part 6/6
Clever Monkeys Part 1
• Part 1/6
• What to look for…
– Similarities to us
Primates in the clip
• Marmosets (Platyrrhini Parvorder)
• Tamarins (Platyrrhini Parvorder)
Primate Physical Traits – 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
• Precision grip possible only with some Primates
– Partially opposable great toe
– Tactile pads enriched with sensory nerve fibers at
the ends of digits
Primate Physical Traits – Teeth
• Omnivorous
• Incisors for biting and cutting; premolars and
molars for chewing and grinding
• Dental formula
– Old World anthropoids have two incisors, one
canine, two premolars, and three molars on each
side in both upper and lower jaws: 2.1.2.3 (32
teeth total)
Primate Physical Traits – Vision
• Stereoscopic Vision
– Visual images are superimposed on one another.
– This provides for depth perception, or the
perception of the external environment in three
dimensions.
Primate Physical Traits – Vision
cont.
• Binocular Vision
– Vision characterized
by overlapping visual
fields provided for by
forward-facing eyes.
– Binocular vision is
also essential to
depth perception.
Primate Physical Traits – Vision
cont.
• Color Vision
– Diurnal primates have it, nocturnal ones don’t
Primate Physical Traits – Smell
• Primates have a decreased reliance on the
sense of smell.
– No rhinarium = worse sense of smell
Primate Physical Traits –
Locomotion
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Quadrupedal, walk on all fours (Baboon)
Vertical clinging and leaping (Indiri)
Brachiation (Gibbon)
Knuckle walking (Gorilla/Chimp)
Primate Physical Traits – Neocortex
• The Neocortex makes up the outer portion of
the Cerebrum. The larger the Neocortex the
more social the animal.
Human
Cerebrum
Gibbon
Wolf
Primate Physical Traits
Evolutionary Factors
• Changes in diet,
reliance on vision,
grasping hands and
feet came about with
arboreal settings,
forward-facing eyes
(facilitate binocular
vision), rise of
angiosperms
(flowering plants)
Clever Monkeys Part 2
Part 2/6
What to look for…
Basic Primate Family Unit
Enculturation
Learned Behaviors
The Piper Plant
Social Behavior
Bonding
Grooming
Aggression
Primates in the clip
• Silver Leaf Monkeys (Catarrhini Parvorder)
• White-faced Capuchins (Platyrrhini Parvorder)
Primate Family Units
• The basic social unit among all primates is the
female and her infants.
• Except in species in which monogamy or
polyandry occur, males do not participate in
rearing offspring.
• The mother-infant relationship is often
maintained throughout life.
• Primates produce only a few young in whom
they invest a tremendous amount of parental
care (K–selected) (contrast r-selected)
Enculturation
• Cultural behavior is learned; it is passed from
generation to generation through observation and
instruction.
• Nonhuman primate infants, through observing their
mothers and others, learn about food items,
appropriate behaviors, and how to use and modify
objects to achieve certain ends.
• More complex, chimpanzee culture includes tools
such as termite fishing sticks and leaf sponges.
Social Behavior
• Bonding
– The role of bonding between primate mothers and
infants was demonstrated in experiments at the
University of Wisconsin.
– Psychologist Harlow raised infant monkeys with
surrogate mothers made of wire or a combination of
wire and cloth.
– Other monkeys were raised with no mother at all.
Social Behavior
• Affiliative Behavior
– Hugging, kissing and grooming are used in reconciliation.
– Relationships are crucial to nonhuman primates and the
bonds between individuals can last a lifetime.
– Altruism, behaviors that benefit another while posing risk
to oneself, are common in primate species.
Social Behavior
• Grooming
– Picking through fur to remove dirt, parasites, and
other materials that may be present.
– Social grooming is common among primates and
reinforces social relationships.
Aggressive Interactions
• Dominant actions can keep subordinates away from food and
using weight loss and poor nutrition, threatening
reproductive success of subordinates
• Competition can result in injury and death
Intergroup Aggression
• Primate groups are associated with a home range
where they remain permanently.
• Within the home range is a portion called the core
area, which contains the highest concentration of
predictable resources, and it’s where the group is
most frequently found.
• The core area can also be said to be a group’s
territory, and it’s the portion of the home range
defended against intrusion.
Clever Monkeys Part 3
• Part 3/6
• What to look for…
– Natural selection acting on behavior?
– Reproductive Behaviors and Strategies
• Sexual Selection
– Benefits of Group Living
Primates in the clip
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Toque Macaques
Golden Lion Tamarin
Golden snub-nosed monkey
Emperor Tamarin
Proboscus monkey
Douc Langur of Cambodia
monkey
Natural Selection acts on Behavior
• “A need to try everything is an extraordinary
way to survive in the jungle. Leaves can cure
you or kill you”
The Evolution of Behavior
Behavior constitutes a phenotype, just like
observable, physical traits do.
Individuals whose behavioral phenotypes increase
reproductive fitness pass on their genes at a faster
rate.
Genes do not code for specific behaviors (i.e.
aggression, cooperation, etc.)
Natural selection acts on genetic factors shaped by
ecological setting of past and present
Sexual Selection
• A type of natural selection that operates on one sex,
usually males.
• Long-term, this increases the frequency of traits that
lead to greater success in acquiring mates.
• Sexual selection in primates is most common in
species in which mating is polygynous and male
competition for females is prominent.
• Sexual selection produces dimorphism with regard
to a number of traits, most noticeably body size.
Benefits of Group Living
• Group living exposes animals to competition
with other group members,
so why not live alone?
• Costs of competition are offset by the
benefits of predator defense provided by
associating with others.
• Group living evolved as an adaptive response
to a number of ecological variables.
Clever Monkeys Part 4
• Part 4/6
• What to look for…
– Adaptive behavior
– Intra and Inter-species language and symbols
Primates in the clip
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Howler Monkeys (Platyrrhini Parvorder)
Black and White Colobus (Catarrhini Parvorder)
Red Colobus (Catarrhini Parvorder)
Guenon (Catarrhini Parvorder)
Sooty Mangabey (Catarrhini Parvorder)
Diana Monkey (Catarrhini Parvorder)
White-faced Capuchin (Platyrrhini Parvorder)
Patas Monkey (Catarrhini Parvorder)
Language
• Nonhuman animals haven’t been considered
capable of communicating about external
events, objects, or other animals.
• It has been assumed that nonhuman animals
use a closed system of communication, where
vocalizations don’t include references to
specific external phenomena.
Koko the Gorilla
• The Gorilla Foundation
• Clip of Koko
• Want to volunteer or get a job with Koko at Stanford? Go Here
Koko and Penny Patterson
Clever Monkeys Part 5
• Part 5/6
• What to look for…
– Dominance Hierarchies
– Communication methods
– Stress-related diseases in large societies
– Benefits of group living
Primates in the clip
• Baboons
(Catarrhini Parvorder)
• Geladas
(Catarrhini Parvorder)
Dominance Hierarchies
• Many primate societies are organized into
dominance hierarchies that impose order and
establish parameters of individual behavior.
• Higher-ranking animals have greater access to
preferred food items and mating partners than
lower ranking individuals.
• Dominance hierarchies are sometimes called
“pecking orders” that change throughout one’s life
and are learned
Factors that Influence Dominance
Status
– Sex
– Age
– Aggression
– Time in the group
– Intelligence
– Motivation
– Mother’s social position
Communication
• Basics…
– Any act that conveys information to another
individual.
– Frequently, the result of communication is a
change in the behavior of the recipient.
– Communication may be the result of involuntary
processes or a secondary consequence of an
intentional action.
Communication
• Raised body hair is an example of an autonomic, or
unintentional, response.
• Gestures, facial expressions, and vocalizations are
examples of deliberate communication.
• The fear grin, seen in all primates, indicates fear and
submission.
• Grooming serves to indicate submission or
reassurance.
• Displays communicate emotional states.
Benefits of Group Living
• Predation
– Primates are vulnerable to many predators,
including snakes, birds of prey, leopards, wild
dogs, lions, and even other primates.
– Where predation pressure is high, large
communities are advantageous.
– These may be multi-male, multi-female groups or
congregations of one-male groups.
Benefits of Group Living
• Relationships with Nonpredatory Species
– Many primate species associate with other
primate and nonprimate species for various
reasons, including predator avoidance.
Benefits of Group Living
• Dispersal
– Members of one sex leave the group in which
they were born when they become sexually
mature.
– Individuals who leave find mates outside their
natal group, so dispersal is believed to decrease
the likelihood of close inbreeding.
Clever Monkeys Part 6
• Part 6/6
• What to look for…
– Tool usage
– Intelligence
Primates in the clip
• Bearded Capuchin (Platyrrhini Parvorder)
Intelligence
• 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.