primate ecology part iii

7/31/2019 Primate Ecology Part III

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Terrestrial African Monkeys1) Cercopithicini

a. Chlorocebus (vervet monkey)i. Small (3-4.5 kg), very closely related to the guenons in size and

shape, it is an edge and riverine species, rarely goes into

deepest forest or driest areasii. Locomotion is intermediate, use both the ground and thetrees, somewhere in between Papio and guenons, about 20% of their time spent on the ground, 30% at lower levels, 35% in thecrown of the trees

iii. Opportunistic omnivores, fruits make up 25-65% dependingon location and season, leaves represent 5-40%, flowers are10-35%, grasses are 1-15%, and animal prey makes up 5-40%of their diet, utilize some forest resources

1. Senegal at 17 species of plants, in another study, theyfed on 66 species of plants, though a great proportion is

from Acacia spp. And grassesiv. Go into the trees for most of their fruit and plant food, quick

and agile for searching for insectsb. Erythrocebus (patas monkey)

i. Limited to the northern savannah regions, dry areas wherethey seem to replace the vervet monkeys

ii. Males weigh about 12 kg, females are approximately 6 kgiii. Most terrestrially adapted, almost all of their locomotion and

85% of their feeding on group, slender with long limbs, not well-adapted climbers, use trees to rest and survey landscape,can run up to 35 mph

iv. Depend on three species of Acacia for gums, leaves, andswollen thorns to get ants within, 80-85% of diet during dryseason is made up of one species of Acacia, will sometimes eat fleshy fruits, seeds, flowers, and mushrooms when available

v. Use the ground and sometimes widely-dispersed treesthroughout savannah

vi. Cat-like, sneak up on insect prey2) Papionini

a. Papio (savannah baboons)i. Five species, Pan-African Sub-Saharan species, four of the

species are along this range, fifth is the Papio hamadryas whichis found in Ethiopia and Southwest Arabia

ii. Forest fringe animals, also present in gallery forest, edges of primary or secondary forest, sometimes in rocky or hilly areas,usually found near standing water

iii. Males weight about 20 kg, females are approximately 10 kgiv. Stocky build, arms and legs are about the same length, spend a

great deal of time on the ground, though will feed and rest intrees, P. hamadryas uses the ground slightly more often


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v. Opportunistic omnivore, focuses on a few specific species that are abundant in the area (primarily Acacia spp.), eat seeds,pods, blossoms, saps, cambian layer of bark, leaves, and feedon insects, also feeds on tamarindus indica (kili trees) withsmall nutritious leaves, savannah resources

vi. During wet season, eat blades of grasses, during the dryseason, eat seeds, rhizomes, and corms (underground stems),may make up 90% of dry season diet, most other animals donot eat this resource, very adaptable

vii. May go into the forest in search of fruit, but will not go verydeep into the forest

viii. Hunts a number of relateively large vertebrates, not enoughprotein in insects

ix. P. hamadryas lives in even drier areas that other four species,depend heavily on Acacia (30-90%) and grasses, during dryseason, focus on dry-adapted plants and underground corms,

will not exploit forest resources like other baboons, will onlygo into forest to reach water sources, do not eat many insectsor vertebrates

x. Tend to feed on the ground throughout the savannah, look under rocks for insects, slow and deliberate

xi. Social Organization1. 8-200 animal groups with a mean between 30-50

animals, multi-male multi-female groups2. When groups are smaller, spend much more time

surveying the environment, larger groups are beneficialon the open plains when predation is common (Stacey)

3. Sub-adult males tend to be on the periphery of thegroup, some are slowly integrating from other groups,others migrating out, some alpha males in the core of the group with females, juveniles, and infants

4. Zuckerman (1932) sex and the drive of sex is what maintained group structure, probably not the casebecause of the seasonality of sex and breakdown of structure during these times

5. Washburn and DeVore (1965-70) first to spend longperiods of time in the field, center of social organizationwas the dominant male, kept group stable, not reallytrue, dominance hierarchy and dominant males areactually least stable aspect of baboon groups

a. Altmann and Havsfater - changes occur bydemographic factors (older leaves, younger rises,every 13.3 days) or through fights (occur every21 days)

6. Packer (mid-1980s) all males migrated from natalgroup, 50 animals changed groups, 48 were males, of


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these, 2 were juveniles, 41 were sub-adult or maturemales, 5 were old males (on average every 4.5 years), allolder males had transferred in and all sub-adults hadtransferred out

a. Natal males would migrate out when they

reached sub-adulthood, usually leave in pairsmove into a group with fewer males their ageb. Multiple-transfer males would move into a group

with more estrous femalesc. Dominance hierarchy was not the glue holding

these groups together7. Donald Stone-Sade studied primarily macaques,

familial interactions of kin focusing on matrilines, 79%of nearest neighbors were between kin, only 15%would be expected by chance

a. Studied allo-grooming, 62% were between kin,

other grooming partners were male-femalecouples

b. Males, upon reaching sub-adulthood, would not mate with mothers or sisters, but would duringdominance stage, non-copulative mating, matewith mothers and sisters to prove dominance

8. Imo was a young Japanese macaque, researchers wouldleave sweet potatoes on the beach, she began washingthem in the ocean, traced adoption of this trait throughout the group, first age-mates through hermother, then other age-mates, up to their mothers, 5years later, 80% of 2-7 year-olds had picked up the trait,18% over 7 (all female) picked it up

a. Males were more conservative than females,except before 3 years old

b. At four year old, Imo also sorted oatmeal andrice by separating it from sand in water, 2-4 yearolds were the first to pick it up

9. Females have a much more stable hierarchy, onlychange because of demographic reasons, females inherit dominance through their mother, alphas daughters willmove into hierarchy just below her, youngest adult daughter will be immediately below mother, maintainsstability over time

10. Dominance is not a genetic trait, no reason for their tobe relationship with reproductive success

a. Hausfater found that only about 50% of matingcould be explained by dominance hierarchy


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b. Packer found that there was no correlationbetween number of days spent consorting anddominance

i. Male was more successful if consort relationship developed

ii. Males may have been dominant becauseof their size, may have lost out becauseiii. If two males align to fight off another

male, both will mate no matter what theirdominance position is

iv. Older males had more success than wouldbe expected from their position in thehierarchy, age, tenure in the group

v. Dominant males may get in too manyfights, may have been injured or be tooaggressive for females

vi. General canine condition related tomating, but not dominance

vii. Fatigue of dominant males allows othersto move in

viii. Male selectivity and female choice werenot related to dominance

c. Shirley Strum focused on females first, foundthat males were not the center of group attention

i. Better predictor of mating success wastenure in the group rather thandominance, social finesse allowed them tostay in the group for extended periods

ii. 7 to 8 adults females throughout study,formed sleeping groups with 2-3 adultsmales, same males would have closerelationships during the day, involvedwith only a small subset of the group

d. Barbara Smutz found that every one of the 34females in the group had a special relationshipwith at least one of the 18 males, friends

i. Females had more friendly interactionswith friends than other males

ii. Tense appeasement gestures aroundother males

iii. Males were responsible for intervening indisputes for female and her offspring

iv. 97% of friendly interactions with infantswere with friendly males

e. Rasmussen found that special relationship weremaintained in consortship


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i. Closer proximity and grooming betweenfriends translated into reproductivepresentations by females more to theirfriends than others, males mounted moreoften, clearly not related to hierarchy

f. Bernstein tried to determine relationshipbetween aggression, grooming, and mountingi. Could not correlate with dominance for

any of these traits in any of five speciesg. Fighting, mating, grooming, inventiveness,

priority of access to resources, leader of groupmovement all used as measures of dominance

i. These are not correlated to one another,so dominance is incarnated differently fordifferent species

h. Silk, Alberts, and Altmann found that social

contact and social integration were positivelyassociated with reproductive success of females,these were independent of rank

b. Theropithicus (gelada baboon)i. Wet grasslands in the cool highlands of Ethiopia, gramnivore

(the cow of the primates), grass-eating adaptations found inancient baboons, 90% of diet consists of grasses, some bushes,focus on green grasses during the wet season, seeds at thebeginning of the dry season, during the peak of the dry, dig forcorms

ii. Males weight about 20 kg, females are approximately 10 kgiii. Longer arms than legs, spends almost all of its time on the

ground, sits on its haunches feeding on grassesiv. Only species that is not an omnivore, almost no animal protein

in its diet v. Differences in what they eat are vary by location, certain

species are more or less dense in a given area, focus on Acaciaand grasses, also shoots and tamarind pods, as well as somemore dry-adapted plant species, very infrequently eat vertebrates of invertebrates

vi. Longer arms than legs, sit on haunches and shuffle while thepick grasses at a very high rate

3) Crook and Aldrich-Blake (1968) first study to utilize the scan-samplingmethod that everyone uses now, Jeane Altmann later reviewed thesemethods and was attributed credit

a. Studied three terrestrial primates (Anubis baboon, gelada monkey,and vervet monkey) in sympatry in Ethiopia

i. Vervet monkey are found mainly in gallery forest and at theedge of cliffs where there are thickets and some grasses,sometimes went into the cultivated areas


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1. 135 animals/km2, studied three groups, home rangeswere about 30 hectares

2. Day range was about 700 meters (600-800 m range)3. Use of trees was about 57% of the time, on the ground

about 30%

4. Ate significantly more insects than other species, ate alot of fruits, some flowers, some leavesii. Papio anubis went through all of the zones, range throughout

the entire area, gallery forest, and thicket predominated,though sometimes went into open areas, were chased

1. Mean group size of 20, home range of about 95 hectares,only 26 individuals/km2

2. Day range was about 1220 meters (700-2000 m range)3. Spent about 28% of their time in trees, 62% of their

time on grasses and herbs (ground)4. Ate primarily fruits and seeds, but also a significant

amount of leaves (mostly of grasses)iii. Theropithecus gelada was only found in open grassland and

thicket areas, slept on the cliffs, and were never far from thegrasses, never went into forest

1. One group of 17 animals, small one-male units, 82animals/km2 and home range was 84 hectares

2. Day range was about 630 meters (500-1000 m range)3. Spent less than 1% of their time in the trees, spent

almost 98% of their time on the ground4. Over 90% of their diet is made up of leaves (mostly

grasses)4) Differences in Social Organization

a. Savannah Baboons large group with females in the center(matrilineal organization) with dominant males, migrating and sub-adult males on the periphery

i. Believed that males were expendable, so they would move onthe outside of the group, however this is not the case

ii. Seems that females always have large males (friends) withthem when they move

iii. Rarely restricted by food and water, tend to be fairly wellprotected by predation, though they are still vulnerable toterrestrial predators, sleeping sites are in the forest wherepredation is not common

b. Hamadryas Baboons 12-750 animals in a troop (sleeping group)often found at these rocky outcrops, look a bit like savannah baboongroups, but in the morning, troop with split into a number of smallergroups and disperse as bands for travel to feeding sites, then split intouni-male or all-male groups which act as stable sexual units (1 malewith 1-9 females), band and troop may not be the same the next night,


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certain males seem to stick together in larger organizations in clans(form of male patri-locality)

i. Males are the center of attention, lead the group, herd thefemales and keep them in line

ii. Males are the same from year to year, but females migrate,

male from an all-male group with adopt a daughter from a uni-male group, in uni-male groups with very old male, son maystick around and later usurp power

iii. Live in much drier areas, with rocky outcrops, very few trees,and no riverine forests

iv. Food in highly dispersed, more predation in these open areaswithout forest to provide cover, protective sleeping sites arevery rare, must come together to reduce vulnerability

c. Gelada Baboons look similar to savannah baboon organization, nearcliffs with grasslands nearby, will rarely move 300 meters from thesleeping sites at the cliffs, only permanent unit is the uni-male group

that spreads out each day to feed, sometimes with a number of uni-male groups in bands, and returns to the herd at night

i. Food depends on seasonality, high predation risk on openplains, sleeping sites are only available at the cliffs edge

ii. Females are the focus of the group (not herded), young femalewill adopt a male, female will sometimes form groups tochoose males, if a male dies, female will attract another malerather than a male actively usurping power

d. Patas Monkey (Cercopithecinii) live out in the driest, most resource-poor areas, one-male units with very large home ranges (not anexclusive reproductive unit, non-resident males may join duringreproductive season), females are resident, these are essentially theirhome ranges, group average 22 members with 1:17 sex ratio, malesare there primarily for predator avoidance, males gain knowledge of resources from females

i. Competition occurs between males when in the same groupii. High predation, so most visually obvious animals in the area

without many treesiii. Rowell studied two groups, most of the time, there were no

males in the group, 18 periods of males residence in thesegroup, during 14 of these, males were there for less than 2months, in 4 of these stayed for more than 2 months, morethan one male was in the group several times

iv. Males are much more vulnerable when they are not in a group


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Food/Water Predation (+ high) Sleeping Sites

Savannah Baboon + + + - + +Hamadryas - + + + - -Gelada Baboon + - + + + -

Patas Monkey - - + + - -Arboreal + + + - + +

Asian Monkeys1) Colobinae

a. Presbytis (langurs) has three species groupsi. Semnopithecus found in India, Nepal, Sri Lanka

1. Presbytis entellus (Hanaman langur) very widespreadthroughout the region, sympatric both Kasi species (P.senex in Sri Lanka and P. johnii in India)

a. P. entellus is very adaptable, generalizedfolivore, edge species, large home ranges, andvariable groups structures and sizes

b. P. senex is restricted to the Sri Lankan rainforest,specialized arboreal folivore, focusing on leavesand some fruits when available, small one-malegroups

c. P. johnii are similarly specialized folivores inwestern Indian rainforest

ii. Presbytis Southeast Asia1. Melalophus is a generalized frugivore and folivore, low

canopy, small one-male groupsiii. Trachypithecus Southeast Asia

1. Specialized folivore, focuses on mature leaves, livesprimarily in the high canopy, quadrupedal locomotion,large multi-male and one-male groups

b. Odd-nosed Monkeys Eastern Asiai. Nasalis (proboscis monkeys)

1. N. larvartus is basically a mangrove species whereforests have flooded

ii. Simias (simakobu)iii. Pygathrix (Douc langur)

1. One of the most restricted ranges and most endangeredpopulations in Vietnam, Cambodia, Laos

iv. Rhinopithecus (Golden langur) only genus with more thanone species belonging to it (4)

1. Monsoon or montane forest, well-adapted to coldweather

2) Cercopithicinae


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a. Macaca widest geographic distribution of any primate other thanhumans, 16-22 species, all Asian except for introduced in North Africa

i. Omnivores, edge species, have taken up the niches of theguenons and the baboons

ii. Species from the same group will not be sympatric with one

another, may be sympatric with those from other groups1. Certain species in each group are considered peripheralbecause of their isolated ranges, outside of India andSoutheast Asia

2. Fooden constructed the distribution map that dividesthe macaque species by their primary habitat (broadleaf evergreen or secondary, savannah, and edge forest)as well as sub-tropical and tropical regions

a. There are a number of different overlappingpairs throughout the distribution

3) Sri Lanka Case Study

a. Presbytis senex (Purple-faced Langur)i. More specialized Kasi species, replaced by P. johnii in India

ii. Small groups divided into one-male or all-male groupsiii. Canopy-dweller, focused on central forests, difficult to observeiv. Two species make up the majority of its diet, and many other

species are eaten in very small amounts, if fruit is available,will eat that over mature leaves (which make up the majorityof its diet)

v. Small home range of only 4 hectaresb. Presbytis entellus (Sacred Hanaman Langur)

i. Generalized folivore, much more adaptable, highly terrestrial,eat twice as much fruit and less leaves (primarily immature)

ii. Live in large groups (up to 20-30 indiviudals), usually eitherone-male or all-male

iii. Eats widely dispersed fruits, has larger home range (25hectares)

c. Macaca sinicai. Omnivorous, though 77 percent of its diet consists of fruits,

unlike the other two species, eats a number of animal sourcesfor protein (does not consume enough leaf material to get protein from there)

4) Malaysian Case Studya. Trachypithecus obscura

i. Specialized folivore (58%), significantly more leaf materialii. 7 kilograms, lives in mature rainforest, high canopy-dweller,

slow in its locomotioniii. Live in one-male or all-male, female is the core of the group,

and males migrateiv. Home ranges are smaller, as are day ranges due to

concentration on predicatble, concentrated mature leaves


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b. Presbytis melalophusi. Generalist folivore (35%) and frugivore (48%)

ii. Found in slightly disturbed, secondary, and riverine forest, canbe found in all layers of the forest, jumps more often

iii. Live in one-male or all-male, female is the core of the group,

and males migrateiv. Concentrates on more unpredictable food sourcesc. Macaca nemastrina

i. Broad-leaf specialist in closed-canopy deep forest, highlyfrugivorous (80%), large home range within this area

ii. Tend to be omnivorous (do not have sacculated stomachs forleaves), eat about 10% animal matter

iii. Sleep wherever they stop eating, different place each night iv. Large multi-male groups where females form matrilines and

males migrate, between 35- 50 animals, more cohesive, doesnt have great variability in group size

d. Macaca fascicularisi. Savannah-adapted edge species, spend quite a lot of time on

the ground, often found in riverine areasii. Opportunistic feeders with high selectivity depending on what

is available in each season, much more diverse diet iii. Refuging species (returns to the same sleeping site every night,

central site foragers)iv. Large multi-male groups where females form matrilines and

males migrate, between 20-100 depending on environment,within these groups, may divide into subgroups, come togetherat refuge sites

e. Hylobates syndactylusi. Larger body size, includes more leaves and insects in their

diets, less fruit f. Hylobates lar

Fruits Flowers Leaves InsectsT. obscura 32 10 58 0P. melalophus 48 14 35 0M. nemestrina 80 0 10 10M. fascicularis 64 9 24 4.5H. lar 64 0.4 31.4 4.5H. syndactulus 45 3.6 43 8

5) Mauritius Case Study (Macaca fascicularis)a. Off the east coast of Madagascar, not part of the normal distribution of

macaques, about 500 years ago, Dutch most likely introducedprimates from Java, presumably about 100 individuals before


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colonization (increased population with human influence), populationis now at 40-60 thousands individuals

i. Environment is completely different from Java, diet has nospecies in common with the ancestral population

ii. Human population is dense in some areas, and very few

forested regions remain, the rest is scrub savannah, highlycultivated (primarily sugar cane)iii. Macaque populations are concentrated to areas where there is

forest or savannah (some ideal mosaic areas)b. Not in normal Asian habitat, though habits are the same, diets differc. M. mulatta is located further north the M. fascicularis in their native

range (Southeast Asia), highly geographically distributedd. Extremely adaptable, one of the best models for human evolution,

little information on variation in ecology and behaviore. Captured, collared, tracked for observation, weighed and measured

i. Studied in a protected area that would be used for hunting

deer during some portions of the yearf. Long-tailed (Crab-eating) Macaques males and females have

mustaches and Prussian helmet appearancei. Groups structure is multi-male multi-female, high variation in

group size, from less than 10 to more than 100, sex ratio canrange from 1:1 to 1:5, matrilineal/matrilocal organization,males migrate, males are also dominant, sub-group fission andfusion during the day (similar to savannah baboon feedinggroups) involving females and friends rather than individuals,return to a single sleeping site every night

ii. 8 males, 23 females, 5 sub-adult males, 39 juveniles, 10 infants,home range was 117 hectares (overlap with northern groupabout 55.5 hectares), density of 1.3 individuals/ha

iii. Nearest neighbors, females with infants stayed together,females tended to have males near them, juveniles made surethey were with someone (no real preference), males tendednot to be with other males, sub-adult males are less social

1. Mutual grooming occurs between females and betweenfemales and juveniles, juveniles sometimes groom otherjuveniles, males rarely groom one another

iv. Activity Budget: Feeding and Foraging (29.0%), moving(23.3%), travelling (5.3%), resting (22.0%), auto-grooming(9.2%)

v. Three feeding peaks throughout the day with resting peaks inbetween, similar to other tropical mammals

vi. Move more during March and April when resources are scarcevii. In most of SE Asia, especially where pig-tailed macaques are

sympatric, almost exclusively arboreal, when they are not sympatric, readily exploit terrestrial habitats (close to 80%)over the year, about 50% of feeding time on ground


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viii. Sleep every night at the base of the mountain, refuging is fairlyrare in primates

ix. Predicted diet would be 72.5% fruit and flowers (few species,change seasonally), 24% leaves, and 4.4% animal prey, basedon dentition, believe there is a species-specific dietary pattern,

physiologically adapted1. About 39% fruit, 8% flowers, 23% leaves, insects werearound 3%, about 5% of sugar cane, grasses, stems,molasses, and other (approximately as expected)

2. Very seasonal, fruits would decrease and leaves/grasseswould increase depending on availability (adaptable)

3. Pod-specialists, hard pods with seeds in the middle,seem to concentrate more on these than fleshy fruit

4. 15-30 plants make up their entire diets, though fewerthan five tend to make up over 60%

5. Had a fairly balanced diet between carbohydrates,

lipids, and protein (from leaves and insects), highlynutritious

6. In natural forests, diets tend to be quite similar, even incompletely different environments (same structure,different content)

x. Human Interactions/Conservation1. Some people treat them as sacred animals (Hindu)

a. Actively feed them to maintain the population,leave offerings for monkeys

2. Some people view them as pests (Christians)a. Feature them in their church dinners (Curri de

Jacot, curri no. 2)3. Minor crop raiders (especially sugar cane)4. Extinctions of endemic species have been blamed on

macaques, though it was probably because of humans5. Export of animals for medical research (second largest

exporter to US after China)Asian Apes

i. Gibbons and Siamangsa. Only primates that are true brachiators, swing beneath branches,

hook-like hands, reduced thumb, long arms, long fingers, no tail,upright in posture (orthograde), walk with hands up in the air

b. Some of the only mammals that are true monogamists, trueterritoriality where they defend a specific range

c. Dense rainforest and monsoon forest, completely arboreal in uppercanopy and emergent layer, fastest flightless animals in the trees

d. Social Structurei. Average group size is 4 individual with the range from 2-6, pair

is the most common interaction, though there are variationsfrom this structure


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ii. Lifespan of 20-30 years, may have extra-group mating, 9% of matings were outside of the group

iii. 10% of siamang groups had an extra adult, some hadadditional female with infant

iv. About 1 in 6-7 pairs was a new group forming

v. Both males and females care for infantse. Territorialityi. Must have enough resources in the home range, tighter

relationship between the number of members in the group andthe home range areas, must be able to cover the entire area tomaintain borders of the homer range

ii. Long (loud) calls are used for spacing, but not when they areinteracting (0.2 - 5 vocalizations per day), displays betweengroups occur between 1-5 days (average about 37 minutes),never make contact with opposing individuals, energyexpensive (males move around, females call, groom males)

1. Can tell the species and sex of the animal, may also giveindication of the health of the caller

2. Helps form pair bonds as well as acting as a spacingmechanism

iii. Group Formation1. Animals leave at about 6-8 years of age, nearly full size,

must develop exclusive area to attract matea. Male will establish territory by extending

parents territory (with their help) and takingcontrol of new portion

b. Male or female may replace a dead partner, mayeven be a younger animal from that group (dueto extra-group mating

c. Males may coalesce to create territory, attract female together, whichever gets the female willgain exclusive use of range, other will leave toform new territory

f. Hylobates (11 species) most are allopatric, replace each other,though there are some small areas of overlap where hybrids exist

i. 5-7.5 kg, found throughout Asiaii. Distinct color patters, territorial calls (duets), geographical

distributions between the 11 speciesiii. C.R. Carpenter (studied Howler monkeys first) was one of the

first to study them in 1937 in Thailandiv. Robert van Gulik was a statesman (ambassador to China and

Japan), essay on the gibbon in Chinese folklore, determined thehistorical range from folklore (throughout China, but humanpopulation has caused in to shrink to current southern range)

v. Consume 60-70% fruit (20-30% of which is figs), 30-40%leaves, 2-4% insects, some other supplements


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1. Scattered resources that are not in great quantitiesvi. Sleep in the canopy and emergent layer, tend to be spread out,

female is often apart from the male (up to 100 meters away)1. Female was separated from male by 10 meters or more

over 50% of the time, sometimes as far apart as 30

meters during activityg. Symphalangus (S. sindactylus) siamangs, sympatric with gibbonspecies with which they overlap, do not hybridize

i. 10-12 kg, only found in Sumatra and Malaysiaii. Eat about 30-50% (70% of fruit diet is figs), 40-65% leaves,

approximately10% insects1. Use clumped resources, massed figs and leaves

iii. Sleep in the canopy and emergent layer, tend to be cohesive,male and female will sleep in the same tree

1. Will call when they wake up to separate from othergroups, alternate between feeding and resting

throughout the day2. Will go to their sleeping sites fairly early, about 2-4

hours before dusk, female usually returns before males3. Whole group will be within 10 meters of each other

50% of the time during waking hours, and 75% of thetime they are doing the same activity, 90% of the time,all members of the group were visible at the same time

iv. Predation is not a major threat, pythons and large raptors mayeat young, felids may eat adults

1. Primary threats are humans, warv. After the first 8-10 months, when female begins weaning, male

will carry the infant until it is up to three years old, longer careperiod than in gibbons

ii. Orangutan (Pongo)a. Only found in Sumatra (only 7500 in northwest of island) and

throughout Borneo, historically found throughout Indonesia,deforestation, commercial timbering are primary threats

b. Distribution of body hair, color, facial structure, chromosome number,c. Males are about 180 lbs and females are only 80, most dimorphic of

all primates, males also have throat sack used for loud callsi. Arm-leg length is highest among all apes, hands, fingers, and

toes are slender, reduced thumb and big toe for arborealsuspensory locomotion

ii. Locomotion is slow and laborious (swing branches to reach thenext one, no jumping), often come to the ground to travel(primarily males)

d. Primary forest dwellers, avoid humans, deepest forest fragments,some lowland, montane, and swamp forest, also diptorocarp forest (consisting of only one genus of plants, many species, but no dominant ones, four distinct layers)


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e. Mainly frugivores (63%), but do include some leaves (23%), bark (11%), flowers (2%) and insects (1%)

i. Social insects (mainly termites) like other large primates, eatenprimarily by juveniles and females, not males

ii. Most feeding is done in the high canopy, eat about 7 species

per day, but focus on a few at a time (depending on season)f. Galdikas found that they depend on three sources of fruits, large treeswith large crops of highly preferred fruits (seasonal, but abundant),scattered trees which were common but not very abundant fruit, orscattered stands with many fruits (only times when they cometogether)

i. Overall, rarely occurring and not abundant resources, thus,they require a large home range

ii. Able to eat fruit before it is ripe, while it is still hard because of their size (other primates cannot eat these), also consumethick, hard, and spiny fruits, can detoxify some species of fruit

that other species cannot eat iii. Leaves are eaten very selectively, usually mature leaves, barks

make up a substantial portion of their diet, chew on wedges toobtain carbohydrates (smaller primates cannot do this)

g. Act as pruners that led to more branching and as seed dispersers forover 70% of the species they consume

h. Active for most of the day (11.5 hours of the day), feeding, travellingmake up the majority of this time

i. Have two peaks of feeding with an extended rest periodi. Build nests for sleeping, watch mothers to learn skills required to

construct, also create umbrellas to protect from rain, provide shade,avoid detection (camouflage), and play behavior

i. Tigers and hunting dogs are the only real predators, cloudedleopards are probably too small, crocodiles are extinct in most areas of orangutan density, but traditional predators

j. Social Structure only diurnal primate that lives in solitary, but socialorganization, much like prosimians

i. 1.5-1.8 individuals (solitary or mother with infant)ii. Regular pattern of interactions, usually move alone

iii. Female home ranges are stable over time (5-8 km), there isextensive overlap between females, with very few areas of exclusive use, male ranges are much larger and overlap withother males very little, but with females a great deal

1. Some males have stable home ranges (resident males)2. Some males home ranges are much more flexible,

usually larger than resident, roam more often,sometimes even resident males that will use thismethod

3. Level of overlap between males is dependent onresource availability


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4. Residence is not equivalent to dominanceiv. Rijksen found that adult females were seen to interact

extensively and lasted a long time 18 times over three yearstudy (probably based on friendship rather than kinship)

1. 30 times, adolescents interacted with females (often

times to interact with their infants)2. 63 times, sub-adult males interacted with one another,more sociable than adults

3. Males and sub-adult males avoid other adult males,often have an agonistic interaction, exchange loud callsabout twice a day as distance-maintaining or increasing,can be heard up to a mile apart

4. Receptive females will decrease distance upon hearing aloud call, if not receptive, will increase distance

v. Mating1. When a female is not receptive to a male, an agonistic

interaction may occur (often involves sub-adult males),may be perceived as dominance interaction

2. Consortship initiated by female almost always withfully adult male, male will alter movement pattern tomove with female for extended period, may consort with one male for a short period and then switch toanother, or may stay with him for a long time

vi. Ranging Behavior1. Females spend most of their time in the trees,

sometimes with their infants, day range is about 700meters (rarely over 2.5 km in a single day)

2. Males will move in the trees if branches can support them, but will often come to the ground to travel, maymove 4 km a day (2500 ha home range)

3. Either move slowly within a relatively small area orquickly in a straight-line manner towards a new foodsource

4. Availability of fruit and social interactions determineranging behavior (females may move towards otherfemales, adolescents spend time with other individuals,males move away from other males or towards estrousfemales, females with infants avoid contact)

k. Pongo pygmaeus Bornean speciesl. Pongo abelii Sumatran species

African Apes1) Gorillas

a. Gorilla g. gorilla western lowland Africab. Gorilla g. graueri eastern lowland Africac. Gorilla g. berengei mountainous regionsd. Males are 300-400 pounds, males are about 200 pounds


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e. All subspecies are endangered, difficult to studyi. Robert Yerkes (psychologist who did comparative intelligence)

sent out two researchers to study gorillas and chimpanzees,though they did not last long in the field

ii. Schaller and Fossey studied mountain gorillas in the 1960s and

1970s, some studies continue to the present iii. First to study lowland gorillas was Fay in the 1990sf. Habitat and Locomotion

i. Extremely variable habitats, though primarily in highlyherbaceous areas, density is tied to terrestrial herbaceousvegetation

ii. Found in primary, secondary, edge, bais (swamp forest)iii. 80% of their locomotion is terrestrial, though the often rest

and keep watch from trees1. Very agile in the trees, though they are often too heavy,

females and juveniles go up more often

2. Knuckle-walkersg. Diet

i. Adapted for folivorous diet with an enlarged hindgut andgrinding dentition

ii. Use mainly perennially available herbs and vines, actually helpperpetuate this layer of the forest, limits the growth of largertrees by sitting on the ground and rolling when they rest, thisdestroys any nearby saplings

iii. 3-4 species may make up 60% of their diet (most research hasbeen done on mountain gorillas)

iv. Darcy found that bed straw (up to 30 km a day, contains 25liters of water), thistle, wild celery, and bamboo shoots(terrestrial vegetation) made up 95% of the diet in mountaingorilla, also may supplement with soil

v. 85-90% is leaves, shoots, and stems, but may supplement withbark, pith, flowers, and fruits, though this is very different inthe lowland gorilla species where they will eat 30-40% fruit

vi. Little or no insect material (on purpose)h. Activity Budget

i. Spend most of their time feeding, long rest in the middle of theday

ii. Build nests in the evening, usually on the ground, may move upto 3 meters into the trees if proper support is available

iii. Up to 3 animals in the mothers nest, though at 1.5 years of age,individuals will begin building their own nests

i. Humans were throught to be the only predators of gorillas, thoughapparently leopards will eat

j. Social Organizationi. Small (up to 42 individuals, though average is only 16.9

individuals), cohesive, stable, multi-male multi-female group


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1. 1.7 silverback males, 1.5 black back males, 6.2 female,2.9 juveniles, 4.6 infants

2. Females carry infants for 3-4 years, but there is highreproductive rate

ii. Core of the group is the silverback male, dominant animal,

center of the groups attention, females with infants interact with each other more, males interact with females without infants more

1. Young females leave the group (and sometimes males)at about 6 years old when they reach sub-adulthood,usually do not reproduce until 9 years of age, maycontinue migrating until they have their first infant

2. All-male groups until males leave to form their owngroup with migrating female

3. Some males follow groups with older dominant maleswaiting to usurp power

iii. Group will move about 1 km a day, home range is about 30square kilometers

1. Females are tolerant to one another (not kin-related),but spend very little time interacting

iv. In bais, different groups were found to interact with each otherwith differing levels of agonism, probably depending onprevious interactions

1. Males are not very tolerant of single males or all-malegroups (presumably trying to usurp females)

2) Chimpanzeesa. Pan troglodytes (common chimpanzee) widest distribution of any

age (across equatorial Africa, 4 allopatric subspecies)i. Male weigh 140 lbs and females weigh 100 lbs

ii. Sympatric with gorillas throughout much of their rangeiii. Garner studied them in 1896, animal collector for a zoo

1. First to use recording devices in the wildiv. Habitat and Locomotion

1. Live in all types of habitat, debate as to whether theyare more adapted to savannah or forest

2. Bimodal activity cycle, like most other tropicalmammals, though males feed and move more thanfemales throughout the day

3. Build nests every night, animals up to 5 or 6 years willnest with mothers, up to 5 to 20 meters up

v. Diet 1. Highly omnivorous, fruit is the focus of their diet,

insects and small vertebrates make up a portion of theirdiet as well, use manufactured tools

2. Rare fruit specialists, patches, 60-80% fruit


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3. One of the most diverse diets of any primate, require alarge home range to acquire patchy resources, probablya major limiting factor

a. Supplement fruit diet with buds, flowers, seeds,and some animal protein (social insects, meat)

b. Only 200 reports of kills during first 25 years of observation, 80% were at Gombe, most of thesewere of baboons, fighting over provisionedbananas

c. Since then, about 400 kills have been reported,250 of these were of red colobus monkeys

d. At Gombe, 64% of vertebrate diet, but withincreased human influence have increased to 87

e. At Mahale, a similar increase in portion of thediet made up by colobus from 14% to 56% to83% today, not a natural phenomenon

4. Females and juveniles tend to be the ones who consumethe insects, they are also the ones using the tools

a. Termite Searching break sticks and twigs, lick them so that they are sticky, lick termites off

i. Different ways in different populations,for different termite species

b. Leaves for collecting waterc. Collect rocks and anvils to open nuts (females

are the only ones who break the hardest nuts),only found in some forest in Tai (cultural)

i. Females will teach young how to do this,males do not learn as quickly

5. Males are the ones hunting vertebrates, males arelarger, spend more time on the ground wherevertebrates are more easily caught, males are moreactive and take more chances (not pregnant or caringfor a baby), all similar to Cebus male-biased hunting

6. Food sharing between females and infants (especially inprovisioning), meat is also shared because it is usuallytoo big for one animal

a. In other mammals and birds, females share withoffspring, older will share with younger, andsome males with females

b. In chimp, 80% of sharing was between close kinc. Meat can also be used as a means of coersion

vi. Predation1. High predation rate (about 4%), primarily by leopards2. As in all great apes, human-induced deforestation and

habitat destructionvii. Social Organization


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1. Communities of 50-100 individuals, interact in a fission-fusion manner within, there are no stable sub-groupsother than mother and infant

2. In 498 interactions, 13% were solitary, 69% werebetween 2-6 animals, 9 or fewer animals seen 91% of

the time, and 20 or more were seen 4 times3. In 667 associations, average was 2.6 animals (range of 1-24), mothers with infants tend to be alone (over 50%)

4. Savannah chimps tend to be found in larger groups5. Distribution of fruit resources (if spread, small groups)

and the number of females in estrous (will besurrounded by more than average) determine the sizeof sub group size

6. Social networks seem to develop, particularassociations with friends are seen more often

7. Males have stronger ties to one another (46% of

grooming between males), females migrate out of theirnatal groups

8. Female choice is the major factor in who mates withwhom, male dominance is not as present as perceived

a. Only two real mating studiesi. Promiscuous males and females have

between 1 and 14 pairingsii. Possessive male exerts dominance

iii. Consort male and female go off together,must chose to maintain consort

iv. Most are promiscuous, dominance playsvery little role

viii. Warfare and Male Killing1. In over 200 years of collective observation at 9 different

sites, there have been only 10 cases of males killingother males, 10 other cases of mysteriousdisappearances (probably leopards)

2. Gombe studied since 1962, nothing happened thereuntil 1974, two groups interacted in an aggressive way,competing over provisioned bananas

a. Amount of aggression increased from 0.2 per dayto 5 per day, wanted to close the site

b. The site has been decreased from 30 squaremiles (connected with contiguous forest on allsides), now only 13 square miles, 150 chimps to100, so density has increased, non-contiguous

c. Some poaching and a lot of disease present dueto human influence (development)

3. All sites except Goualougo have experienced a great deal of human influence, population encroachment (16


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times increase at Tai), snare injuries at high rates (255of individuals at Budongo), chimp populations aredecreasing as well

a. Bossou is so highly influenced that only maleremains, move as one group rather that fission-

fusion sub groupsix. Language and Culture1. No chimpanzee teaches its offspring language in the

same way we do, must re-label human language if wecall what they do language

2. There are differences between populations throughout their range, differences do not have serious effects ontheir lives, very unlike human cultural differences

3. Live in the present, cannot express symbolicallyanything not currently present (future, past, absent individual)

x. Many of the unusual characteristics that have been reported donot seem to occur at undisturbed Goualougo nor at Goodallssite during the first 20 or so years, all influenced highly byhumans

b. Pan paniscus (bonobo, pygmy chimpanzee) found only in a smallregion on the northern bank of the Zaire river (restricted range)

i. Males are about 100 lbs and females are 70 lbsii. Not sympatric with gorillas

iii. Habitat and Locomotion1. Diverse habitat, but mostly primary forest 2. Seem to be more arboreally adapted than the

chimpanzee, though both knuckle-walk iv. Diet

1. 80% fruit

primate ecology part iii

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