Primatology Midterm

Behavior ecology

based on development of evolutionary principles to understand adaptive advantages of behavior under different eco conditions

Strategy

behavioral phenotype shaped by natural selection, product of physical and social env and genetic makeup

Longitudinal studies

test hypotheses about behavioral adaptations

Ancestral traits

shared through common ancestry

Derived traits

modified from common ancestor

Primates\=generalists

Isometric traits

scaled with body size, no functional difference

Allometric traits

differ from expected based on body size *functional difference → adaptation

Prosimians

loris, lemurs, tarsiers

Strepsirhines

loris and lemur

Anthropoid

monkeys, apes, humans

Haplorhines

tarsiers, monkeys, apes, humans

Strepsirhines

Grooming claw, Dental comb, Longer snout, Rhinarium, Postorbital bar, no plate, Tapetum, Nocturnal, Lack color vision, Reduced upper incisors, Pseudo-opposable hands

Aye-aye

very specialized, nocturnal, Relatively large body size, Dental 1.0.1.3./1.0.0.3, Large front teeth, Large ears, Filiform 3rd digit for tap scanning

Lorisiformes

lorises and bush babies

**Diet: specializations gum to fruit to insects**

**Locomotor: VCL (galagos) and arboreal quadrupeds (loris)**

**Communication:** 

* **Scent glands** 
* **Vocalizations (galagos)** 

**Social systems:** 

* **MM/MF**
* **Solitary** 
* **SM/SF**
*  **SM/MF**

**Life histories:** 

* **Single births and twins** 
* **Infant parking** 
* **Adult males interact w young** 

lemuriformes

* **Variation in body size**
* **Diurnal and nocturnal** 
* **Arboreal and terrestrial** 
* **Diet: gum to fruit to insect**

**Locomotion: VCL and quad walk/run** 

**Communication: scent glands**

**Behavioral traits:** 

* **Female dominance in most species** 
* **Seasonal breeding in most species** 
* **Cathemeral species** 

Platyrrhines

new world monkeys

Catarrhines

old world monkeys, apes, humans

Platyrrhine characteristics

Arboreal
Pseudo-opposability
dental formula

Atelidae

spider monkey, howler, muriqui
Largest NWMs
Prehensile tails
Semi brachiators

Aotidae

night monkey
Only nocturnal monkey
Monogamous
Significant paternal care

Pitheciidae

sakis, vacaris
Similarities in diet
Variation in group size, diet

Cebidae

capuchin, squirrel monkey
Slow life histories
Similarities in diet and social org
Courtship rituals

Callitrichidae

tamarins, marmosets, goledi’s
Small to very small
Claw-like nails all digits but hallux
Visual and olfactory communication
Marmosets

Tarsiers
Like strepsirrhines

Small
Nocturnal
VCL
Grooming claws
Infant parking

Tarsiers Like haplorhines

No rhinarium
No dental comb
No tapetum
Postorbital bar

Anthropoid traits

Increase in body size
Greater vision
More precision in hands
Geographic expansion

Catarrhine

old world monkeys → separate from OWM 40 mya
All diurnal
Terrestrial and arboreal
Body size
Dentition
Grasping abilities-flat nails, more opposability
Ischial callosities
Sexual swellings and body decorations

Cercopithecines

Macaques, baboons
Less space between eyes
Broad incisors
Shallow jaw
Low cusp molars
Cheek pouches
Similar arms and legs
Short tails

Colobines

More space between eyes
Narrow incisors
Deep jaw
High cusp molars
Complex stomach
Longer legs
long tail

Orangutan

Sexual dimorphism
Secondary sex characteristics

Gorilla

Largest of apes
Extreme sexual dimorphism
One or two male (silverback) multi female group
Knuckle walkers

Chimpanzees and Bonobos

Multi-male multi female
Knuckle walker
Sexual dimorphism

Adaptive traits

increase survival and RS of indvs and should be favored by NS

Altruism

selfless behavior that benefits another at cost to actor

Natural selection

favor altruism → kin selection (help fam\=reproductive success), inclusive fitness

Hamilton’s rule

altruistic acts selected for when cost to actors fitness is greater than the benefit to recipients fitness times degree of relatedness

Expectations

altruism should be limited to kin, closer kin \= more costly acts, ability to recognize kin

Hominoidea

Apes, 3 families → differ from monkeys
Brachiation-IM index and clavicle
Lack tail
Dentition (Y5 molars, simple)
Larger brain
Broader nose and palate
Long arms and short trunks

Hylobatidae

gibbons and siamangs
True brachiators-long arms, arboreal, hook grip
Most vocal of all non human primates
Socially monogamous
Ischial callosities

Pongidae

orangutans, gorillas, chimps, bonobos
Sexual dimorphism
Lack ischial callosites
Locomotion on ground

Himinidae

humans and human ancestors

Cenozoic era

adaptive radiation of mammals after dino extinction

Plesiadapiforms

possible primate ancestor, lack many primate features

Paleocene to eocene

warming, tropics → adaptive radiation of primates

Euprimates

appear in eocene, true primates
→ adipoids and omomyids

Eocene to oligocene

cooling, euprimate extinctions, NWM split from OWM

Oligocene to miocene

warming, radiation of catarrhines, proconsulids in Africa

Early miocene

apes dominate, heavy forests

Late miocene

monkeys dominate, adaptive radiation, forest and savanna

Proconsul

early ape ancestor
Ape skull and teeth
Monkey-like proportions and wrist

Sexual selection

acts on traits that affect differential reproduction among same sex individuals
Strategies for finding mates differ between males and females
Factors limiting reproduction for each sex

Reproductive potential

females limited by number of offspring they can carry, males limited by access to females

Limiting factors Females

fertilization gestation and lactation
Heavy investment
Potential limited

limiting factors males

number of mates they can acquire
Greater potential
More variation of offspring amount between ales

Sexual dimorphism

high \= intense competition

Influences on Male competition

Solitary vs group females
Seasons vs synchrony
Inter-birth intervals
Monopolies
Operational sex ratio

Consequences of asymmetry

Females are limited resource → more male male competition

Repro mistakes more costly for females → selective in mates

Seasonal breeders

pressure for males to access females and keep others away, females to get pregnant

strategy: mate with multiple Indvs

low sexual dimorphism

competition during mating season

male weight gain

Solitary Females
Monogamy

Paternity certainty, high paternal investment, protection against infanticide, similar reproductive success between males and females, relaxation of selection pressures.
Low sexual dimorphism, sexual monomorphism

Polygyny (One male many solitary females)

High reproductive success for territorial males, less time and energy finding food for solitary females, high male competition, bimaturism in males due to selection pressure,
High sexual dimorphism, arrested development

Polyandry

Cooperate in caring for offspring, male hierarchy, females with rapid reproductive rates need more help caring for offspring, female requires large feeding area and needs multiple males to defend, males have skewed reproductive success rates
Low to mid sexual dimorphism

Polygamy (Multiple males, multiple solitary females)

Males form alliances for advantages over solitary males, areas with many independent females, competitive advantage over smaller groups of males, related males forming alliances, competition within alliances, higher ranking males have more reproductive success but do not monopolize it, females mate with multiple males
Medium sexual dimorphism

Group-Living Females
Single male

Female group size effects number of males, age grade system (son is allowed to stay in group, repels attacks and inherits breeding group), doesn’t always mean higher reproductive rates for males, competition from outside males, less mouths to feed can be beneficial for females, male who is able to defend the group will be supported by females
High sexual dimorphism

Multiple males

Higher number of females makes it harder for one male to monopolize, protection from predators and defense of resources, competition within group, dominance hierarchies, female interest not necessarily including fidelity to males in group, extra-group copulations to boost reproductive opportunities, easier for males to survive in group
High sexual dimorphism

Female RS and Diet

RS linked to nutritional status

Benefits associated with high nutrition

Reproduce earlier, healthier offspring, shorter inter-birth intervals, longer lives
Variation in nutrition variation in RS

Ecological release

in the absence of competition, return to a preferred condition

Foraging

includes looking for, handling and eating food

Frugivores

Often a preferred food Variable in caloric contest, digestibility, quality of vitamins, minerals, water, fall back foods are seeds and bark

frugivore adaptations

large, broad incisors
low-cusped
relatively flat molars
relatively large unspecialized digestive system, strong jaws, powerful chewing muscles, thick enamel

Folivores

Vary in fiber content and digestibilty depending on maturity Mature versus young leaves

folivore adaptations

Sharp, shearing crests on molars

Plants with chemical deterrents

Found in higher levels in mature levels Tannis (bind to plant proteins in digestive track), alkaloidsboth in higher levels in mature leaves

Charcoal to detoxify (red colobus monkey observed to consume this) Clay neutralizes

Gumnivores

High energy
Easily digestible (its good for all, but extremely difficult to get to it) Calcium → skeletal development

gumnivore adaptations

long , robust incisors/dental comb
Claws

Insectivores

Protein source
Easily digestive - shorter gut
If you cannot eat leaves (digestabilty, body size)

insectivore adaptations

high , sharp crests of molar teeth Simple digestive system

differentiation of diet

reduce and change competition between the sexes and species

relationships to diet

tool to interpret eco diversity, sexual dimorphism

Feeding strategy variables

quality of food, spacial distribution of food, availability of food

high-quality

growth diets (reproductive advantages), preferred

low quality

subsistence foods, fallback foods

large primate diet

low quality high volume, fruits and leaves

small prime diet

high quality low volume insects and fruits

small bodied animal metabolism

allometric relationship btw body weight and basal metabolic rate high energy required for smaller primates and then starts to level off
small animals spend a larger amount of energy as a % of body weight than large animals do
small animals burn off energy faster — need greater energy in smaller packages

impact on weaning ages/RS

higher quality foods → quicker weaning and higher RS

factors that influence diet

active metabolism → increase quality of the diet growth
reproduction

impact of sexual dimorphism (males vs females)

where they can feed (females higher in canopy, males on ground → less competition)

Spacial Distribution of Food

determines amount of time and energy foraging
costs vs benefits of foraging strategies
distribution of high quality vs low quality resources

Home range

spacial area used by a primate group
can be limited or many square km
must contains all resource

primate territoriality

actively defended against members of the same species

key resources primates would risk to protect

\

defend

food limited and clumped (fruits, flowers, gums)

not defend

abundant and widely distributed or evenly distributed and hard to defend (leaves)

Fluid groups

primates adjusting feeding strategies in response to ecological pressures

Size of home range related to

availability of preferred food source
number of group members

Group living costs

within group comp and comp for mates

group living benefits

predator defense and food access

options that primate have when there is seasonal variation

increase dietary diversity
alter home range or group composition reproductive seasons, breeding seasons