Exam 2 Flashcards
what is a mammal?
- warm blooded
- fur/hair
- some development inside of mother (live birth)
- milk
- three middle ear bones
warm-blooded animals
maintain a constant body temperature, typically above that of the surroundings by metabolic means
cold-blooded animals
having a body temperature varying with that of the environment
endothermy
- means of thermoregulation
- the ability to control body temperature through internal means
- means include shivering, increasing metabolism
- difficult to disentangle structures and functions responsible for or merely affected by endothermic physiology
adaptions that coincide with warm-bloodness
- more efficient metabolism
- greater oxygen intake abilities and nutrient uptake
- large lungs, diaphragm, improved circulation
- more efficient method of removing waste, improvements to kidneys and the separation of urinary and fecal tracts
adaption of fur-hair
thought to be an insulating mechanism, helps to retain the heat your body generates and plays a sensory role (whiskers)
adaption of scales/plates
absorb sun’s heat for quicker mobilization - important if you rely on external heat for energy as reptiles
what are the three live birth subdivisions of mammals?
- monotremes
- marsupials
- placentals/eutherins
monotremes
- echidnas, platypus
- lay eggs into pouch
marsupials
- kangaroos, opossums
- birth live young, carry in pouch
placentals/eutherians
- elephants, primates
- presence of a placental facilitates exchange of nutrients and wastes between the mother and fetus
- offspring gestate entirely inside the mother and acts as a blood barrier
milk production
- a nutritious liquid produced by the mammary glands of mammals
- the primary source of nutrition for infant mammals
- genetic evidence of a tradeoff reduced number of egg yolk genes coincides with the arrival of milk producing genes
what are the three middle ear bones?
- malleus, incus, and stapes
- one lower and one upper jaw bone connected to the existing stapes
what is the purpose of the ear bones?
- ossicles
- a series of levers that improve transmission of sound from the eardrum to the inner ear, and increase frequency limits
- match the vibrations in the air to vibrations to liquid in the cochlea
- reptiles retain only the stapes
what are the nocturnal adaptions?
- warm bloodedness (you don’t need the sun directly for energy)
- insulation
- increase reliance on olfaction, hearing, and touch, decreased reliance on vision
what did early mammals look like?
- very small
what is kay’s threshold?
about 500 grams
who were the first mammals?
- synapsids
- therapsids
synapsids
a group of mammal-like reptile
- 310-275 mya
therapsids
a branch of synapsids with mammal-like features
- 275-225 mya
when were mammals as we know them today in the fossil record?
- between 180 to 130 mya
- mainly small, shrew-like mammals
when did mammals start to become common? why?
- mammals were not as common before 65 mya (cretaceous-paleogene boundary) but then explodes afterwards
- KT boundary
- many niches were left unoccupied for mammals to exploit
when did primates start to appear?
eocene - paleocene
56.5-65 mya
lepticidium
x
paleochiroptyrix
x
propalaeotherium
x
darwinius
x
how are order defined?
by their relatedness
- generally identified by suites of characteristics they share
rodentia
- gnawing mammals, incisors continue to grow throughout their lives
- squirrels, mice, rats
chiroptera
- only flying mammals, the wings are actually skin stretched between their phalanges
- also have echolocation for night hunting
cetacea
- aquatic mammals, blowhole, echolocation
- dolphins, porpoises, whales
proboscidea
- trunks, tusks,
- only found in africa and asia
- elephants
what does primitive mean?
- more closely related resembling the common ancestor to the group (ancestral trait)
- does not mean less successful or less evolved
what are the 13 primate features?
- pentadactyly
- opposable thumb/toe
- nails instead of claws
- retention of clavicle
- two separate bones in the forearm and leg
- reduced snout/olfaction
- generalized skeleton
- generalized dentition
- bony eye socket
- petrosal bulla
- expansion and increased complexity of the brain
- life history
- forward facing eyes
pentadactyly
5 fingered
opposable thumb/toe
- thumb can reach finger tips
- allows grabbing and grasping
what primates are the exception to the opposable thumb/toe?
- gibbons lost both
- humans do not have an opposable toe
nails instead of claws
- essential for grip
- found on atleast on digit of all primates
two separate bones in the forearm and leg
allows for greater flexibility and turning
reduced snount/olfaction
- olfaction bulbs smaller
- face gets shorter and flatter
- decreased reliance on smell/scent communication, scent based-location of food, instead rely more on vision
generalized skeleton
unspecialized skeleton allows for variety of locomotion
generalized dentition
- heterodont (incisors, canines, premolars, and molars)
- dental formula varies
- general teeth reflect varied diet (most primates are omnivores)
bony eye socket
protects the eyes
petrosal bulla
- small bony cover that protects the inner ear
- only trait unique to primates
- other mammals have an auditory bulla
expansion and increased complexity of the brain
- reduced olfactory region
- increased cerebrum
- larger brains relative to body size
life history
- longer lived than most mammals
- longer gestation (later age at first birth and fewer offspring)
- longer period of dependency
- brain growth and learning
- born altrical
forward facing eyes
better depth perception and total visual field
superfamily: lemuroidea
includes all the lemurs from madagascar
- lepilemuridae
- lemuridae
- indriidae
- cheirogaleidae
- daubentoniidae
madagascar
4th largest island on earth
- 450 km off east coast of africa
- endemic mammals with extraordinary diversity (lemurs are critically endangered)
- primates in all habitat types
fossil record of madagascar
- breaks off from india 120 mya
- first fossil evidence of primates from as early as 60 mya
how did primates get to the island of madagascar?
- The early primates that colonized Madagascar were
small, with nocturnal features - The likely floated across the Mozambique channel
(which was much narrower at the time), due to
prevailing currents (which flowed east toward the
island at the time)
what is an example of what the first lemur ancestors looked like when they arrived in madagascar?
modern cheorogaleid
how many species of lemurs are there?
100
what are sub-fossil lemurs?
17 species that are recently extinct
- koala lemurs, sloth lemurs, monkey lemurs, pachylemur, and the archaeoindris
when did humans start to colonize madgascar?
about 2000 years ago
what group of animals is the most endangered on earth?
lemurs
what percentage of lemurs are critically endangered?
31%
what percentage of lemur species are endangered?
98%
what are the four genera of lemuridae?
eulemur, varecia, hapalemur, and prolemur
what is the diet of lemuridae?
fruits and leaves, some eat bamboo (hapalemur)
what is the locomotion of lemuridae?
general arboreal quadrupedal
- cathemeral (day and night)
what are the three genera of indriidae?
indri, avahi, and propithecus
what is the diet of indriidae?
mostly leaves, follivory
what is the locomotion of indriidae?
- vertical clinging and leaping
- mostly cathemeral but avahi are nocturnal
what is the size of indriidae?
- varied, from 770-6800 g
- avahi are small while indri are large
what are the five genera of cheirogaleidae?
- dwarf and mouse lemurs
- microcebus, cheirogaleus, mirza, phaner, and allocebus
what is the diet of cheirogaleidae?
animal prey, gum and leaves
- nocturnal
what is the social behavior of cheirogaleidae?
females stay with offspring and males roam over multiple female ranges
- females have 3 pairs of nipples and bear 2-3 young
what is the genus of lepilemuridae?
- sportive lemurs
- lipilemur
what is the diet of lepilemuridae?
mainly leaves
- eat feces/dung (coprophageous)
what is the body size of lepilemuridae?
small, about 500-1000 g
what is the locomotion of lepilemuridae?
- VCL, 100% arboreal
- nocturnal
what is the genus is daubentoniidae?
- aye aye
what is the diet for daubentoniidae?
animal prey, fruit, fungus, seeds
what is the social behavior for daubentoniidae?
noyau, solitary foraging
what is the locomotion for daubentoniidae?
arboreal quadrupedalism
- nocturnal
lorisida diet, social, body size, life span, and locomotion
- Diet: animal prey (insects), fruit, gum, + leaves
- Nocturnal
- Social: Noyau
- Body Size: Small (210-1600g)
- Life Span: ~20 years
- Locomotion: VCL
Galagidae diet, social, body size, life span, and locomotion
Diet: animal prey (insects inverts), fruit, gum, + leaves
* Social: (male’s range overlaps with >1 female’s range).
* Nocturnal activity pattern
Body Size: small (80-1500g)
* Life Span: ~15 years
Locomotion: Arboreal Vertical Clinging and
Leaping (VCL)
where are Galagidae located what makes them unique?
distribution: sub-saharan africa
Excellent vocal communication (highly specific), with
prominent, mobile pinna and derived (enlarged) middle ear
Reproduction: Birth singletons, ‘park’ young while foraging…
what are special features of strepsirrhines?
Adaptations to enhanced olfactory ability
* Moist rhinaria (wet noses)
* Longer snouts (prognathism)
* Large olfactory bulbs
* Vomeronasal organs (detect non-VOC chemical cues,
require direct contact with odor source)
What do strepsirrhines use olfaction for?
- Finding the best food
- Recognizing kin and nonkin
- Fighting
- Flirting
describe the vision of strepsirrhines
- nocturnal or cathemeral
- Most have a tapetum lucidum
- Divergent eye orientation (for a primate), decreased visual acuity and likelihood of trichromacy
what are adaptions to pronounced seasonality?
- behavioral adaptions like seasonal breeding
- lack of male-biased sexual size dimorphism
what is male-biased sexual dimorphism associated with?
- associated with male-male contest competition - over access to females
what is the smallest primate in the world?
- madame berth’s mouse lemur
- weighs 30 g
fork-marked lemur diet
gum
prolemus and hapalemur diet
bamboo
what are the main predators of lemurs?
fossa, reptors, and snakes
- lemurs have the highest predation amongst themselves
what are anti-predator strategies in lemurs?
alarm call, mobbing, crypsis, and toxic bites
what are the activity patterns of lemurs?
nocturnal, cathemeral, crepuscular, and no strictly diurnal species
what bony features distinguish strepsirrhines from haplorhines?
- unfused mandibular symphysis in streps
- unfused frontal suture in streps
- postorbital bar but no postorbital closure
- grooming claw on the second or second and third digit of the foot - haps do not have
- streps have a tooth combs
what is the dental formula for stepsirrhines?
2.1.3.3.
except aye aye have 1.0.1.3 or 1.0.0.3
tarsiidae characteristics
- haplorrhine
Old World: Island SE Asia - very specialized, rat-sized
- vertical clingers and leapers
- nocturnal, insectivorous
- large eyes – enclosed orbits, larger than its brain and stomach
- lack rhinarium & dental comb
what is the diet, social behavior, and locomotion of tarsiers?
Diet: insects, reptiles, birds, worms (100%
faunivorous)
* Social Behavior: Noyau system mainly (i.e.,
solitary males overlapping with several
females (and their respective ranges), but
other spp. live in groups
* Locomotion: vertical clingers and leapers
(VCL), hyper-specialized
what is the distinctive morphology between platyrrhines and catarhines?
nasal morphology
- platy = flat
- cata = down flowing
what percentage of primates are monkeys?
85%
diversity and biogeography of platyrrhines
- tropical and sub-tropical americas
- 5 families: atelidae, pitheciidae, cebidae, callitrichidae, and aotidae
- arrived in the new world from africa 50 mya
what are the general characteristics of platyrrhines?
- Narrow ecological variation/less adaptive diversity compared to streps and cats
- Adaptive radiation accompanied by unique
morph. features (e.g., prehensile tails) - Primarily diurnal (unlike streps) and arboreal
- Diverse variation of mating systems
- All have a dental formula of 2.1.3.3 (same as streps)
what is the diet of platyrrhines?
most are frugivore omnivores
what is the predation of platyrrhines?
- Both large and small species preyed upon
- Constricting & venomous snakes
- Felids
- Domestic animals
- Raptors
- And even other monkeys
describe platyrrhine locomotion
- No habitual terrestrial NWM
- Almost exclusively arboreal quadrupeds
- will come to the ground for water, mineral licks, forage for insects, cross pathways in the forest, play, and to escape predators
what are the platyrrhine mating systems?
- Monogamy (ish)
- Polygyny
- Polyandry
- Polygynandry
platyrrhine atelidae 4 generas
- alouatta - howler monkeys
- ateles - spider monkeys
- lagothrix - woolly monkeys
- brachyeles - muriqui
dispersal patterns of atelids
- Generally unusual dispersal patterns
- Atelids = female dispersal
- Atelid groups not typically matrilineal
which group belongs to fission-fusion societies like chimpanzees and bonobos
ateles - spider monkeys
which group of platyrrhines have a prehensile tail
- parallel evolution
- spider monkeys and capuchins
what is the mating procedure of atelids?
- Mate promiscuously
- Females mate w/multiple males
- Males mate w/multiple females
- Very little aggression b/t males
- No reproductive skew
how do atelidaes communities live?
- All genera of Atelidae live in multi-female, multi-male
grps EXCEPT Alouatta (howler monkeys) - 1 adult male per grp (polygamous), seldom more than
3
why are alouatta unique in the group of platyrrhines?
1) Are highly folivorous
2) Are the only platyrrhine to have evolved routine
trichromacy
3) Make the loudest sound of any land animal (can be
heard ~5km away)
4) Size of their hyoid bone/ability to loud call is
negatively associated with testicle size!
what are the four genera in the family of pitheciidae?
- Callicebus- titi monkeys
- Pithecia- saki monkeys
- Chiropotes- Bearded saki monkeys
- Cacajao- Uakari monkeys
where are pitheciidae located and what do they eat in these areas?
- Found mainly in Brazilian Amazon, from lowland swamp forest to mountain slopes.
- Some species are frugivorous, some are specialized seed predators – seed predation is generally uncommon amongst primates
what is the social organization of titi monkeys?
a life-mated adult pair with 2-4 young
where uakaris live?
all live in the northwestern amazon basin
- have been seen singly or in groups of over 100
- four different types of species
what are the genera of cebidae?
- Cebus/capuchins
- Sapajus/also
capuchins - Saimiri/squirrel
monkeys
what is the social behavior of cebids?
Usually live in large multi-male/multi-female groups
* ~30 individuals
* Dispersal predominantly male (sometimes multiple males
* together) – All Male Bands
* Female philopatry and strict female hierarchies
social beahvior of capuchins (cebus)
- Promiscuous mating
- Extreme male reproductive skew!
what is the diet of capuchins?
- Highly adaptable, found in almost all landscape types, including anthropogenic landscapes
- Eat everything they can!
what are the genera for Callitrichidae, Marmosets/tamarins
- Cebuella
- Callibella
- Callithrix
- Mico
- Leontopithecus
- Saguinus
- Callimico
what are Callitrichidae?
The dwarf monkeys – smallest body sizes amongst
haplorrhines
what is the unique features of callitrichines?
- re-evolved claw-like nails
- derived feeding adaptions: gums, sap, and embedded insects
reproduction activities of callitrichidae
Female reproductive competition = prominent and
unusual amongst primates
* Reproductive skew
* Breeding monopolized by dominant female
* Physiologically or behaviorally suppresses
other female fertility
what is the only nocturnal NWM?
aotus - owl monkeys
- monochromatic and only see in black and white
what is the reproductive activity of owl monkeys?
- Monogamous
- Small groups, single adult pair & offspring
- Both defend territories
- Male is often the primary caregiver
- Monogamous but more complex than thought
- Extra pair copulations
what is NWM
- limited ecological variability vs other primates
- anatomy and social systems are extremely diverse
- several unique morphological features such as claws and prehensile tails
monochromacy
one cone type
dischromacy
red and green color blind
trichromacy
three cone types
tetrachromacy and pentachromacy
4-5 cone types
polymorphic trichromacy
- Everyone gets a short-wavelength sensitive cone
- The medium- and long-wavelength sensitive cones are on the X chromosome
- Males only inherit one X – therefore, they get either a M or L cone, in addition to the autosomal SWS
- Females inherit two Xs – if the cone type on each X chromosome is different, she will have three cone types and therefore be trichromatic
what are the two superfamilies catarrhines are split into?
- cercopithecoidea (old work monkeys)
- hominoidea (apes)
cercopithecoidea are split into what two major groups?
- colobinae, leaf eating monkeys
- cercopithecinae, cheek pouch monkeys
diversity and biogeography of cercopithecines
- Most genera occur in Africa
- Macaques (Asia)
- Found in diversity of habitat types (e.g., rain forest,
gallery, swamps, savanna, woodland etc.)
what is the general body size of cercopithecines?
- Most medium-sized (4-12 kg)
- Heaviest sp. spend most time on ground (e.g., mandrills, baboons, geladas)
- Sexual dimorphism in all species
- canine dimorphism between males and females
what is the life history of cercopithecines?
- Variation in breeding seasonality
- All give birth to singletons
- Age at 1st reproduction typically 4-5 years
what is the diet of cercopithecines?
diverse diet of fruit, seeds, flowers, leaves, shoots
what animals are predators of the cercopithecines?
- Large cats
- Raptors
- Snakes
- Crocodiles
- Other primates
- Humans
what are some anti-predator strategies of cercopithecines?
- Mobbing & chasing (Limited to adult males in large
bodied species ) - Alarm calls
- Flee silently (e.g., mona, white-throated, &
DeBrazza’s monkeys)
what is the social organization of cercopithecines?
- All cercopithecines live in groups
- Strict female philopatry/Male dispersal
- Except Hamadryas baboons
what are the mating systems of cercopithecines?
- Polygynous
- Polygyandrous
- In many species, females have sexual swellings &
copulation calls –
what are female-female relationships in cercopithecines?
- Female philopatry = complex f-f relationships
- Strongest bonds w/kin
- exception Hamadryas baboons
- Female rank = important fitness consequences
- Coalitions & Cooperative relationships
what are male-male relationships in cercopithecines?
- Agonism rates can be high (access to mates, dominance)
what is the diversity and biogeography of colobines?
- Inhabit Africa (Colobus and Procolobus) &
Asia (2 grps. Langurs & odd-nosed monkeys) - All species arboreal (exception Hanuman langur)
what is the diet of colobines?
- Leaves (Proportion can vary)
- Fruits & seeds also important
- Flowers, insects, and soil (smaller portion of diet)
- Food selection affected by food quality
(protein to fiber ratio, secondary compounds)
what is the digestive system of colobines?
- Specialized enlarged gut & partitioning of
stomach - Enlarged caecum & colon
- Fore-gut fermentation
what are the main predators for colobines?
- Carnivores
- Snakes
- Raptors
- Chimpanzees
what are some anti-predator strategies used by colobines?
- Poly-specific associations (African colobines)
- Alarm calls
what is the life history of colobines?
- Females give birth to singletons
- Many sp.- IBI ~2 years
- Age at 1st reproduction varies
- Allo-mothering = common
how are colobine social systems different than cercopithecines?
- Smaller home ranges
- Smaller groups
- No coalition behavior amongst females
what is the social organization of colobines?
- Groups vary in size & composition
- Most species are one male/multi female (polygynous)
- Pair-living w/offspring (only two spp)
- Multi-male/multi-female groups rare (>300)
which species participate in pair-living?
- Only found in 2 colobine sp. (Southeast Asia)
- Mentawai Islands
- Mentawai surili & pig-tailed snub-nosed monkey
do colobines participate in harem?
- yes, one male and many females
- Single male can monopolize several females
- Males father majority of offspring
- Commonly, males disperse/female philopatric
what are surplus males in colobine populations?
- Many sp. with female philopatry have dispersing
males living alone or in all male bands - Individual males can form bands to take over other
groups
do colobines participate in infanticide?
- Stops lactational amenorrhea
- Females begin cycling again
- Very costly for females!
how do females counter infanticide?
- Solicit matings outside period of receptivity
- Mate promiscuously
- Form coalitions
- Wean infants early
what are the general characteristics of old world monekys?
1) All display some degree of sexual dimorphism
2) Are mostly arboreal and diurnal
3) Split into cheek pouch monkeys and leaf eating
monkeys
4) Have routinely trichromatic color vision
what are the two families catarrhine is split into?
hylobatidae and homindae
hylobatidae
- gibbons and siamangs
- 18 species across 4 genera
- live throughout asia in india, bangladash, china, and indonesia
what are the three ways hylobatidae differ from hominidae
- smaller
- lack sexual dimorphism
- do not make nests
what are some unusual features about hylobatidae?
- Unusual amongst mammals in that males and
females pair-bond - Unusual way of maintaining territory –pair-bonded
males and females DUET –sing together to inform
other families of their whereabouts
how fast can true brachiators travel?
True brachiators –can travel 35 mph through the
canopy, and cross up to 35 feet of forest gap
what are the four genera of hominidae?
- 9 species in 4 genera
- gorilla
- pongo (orangutans)
- pan (chimpanzees)
- homo (humans)
what are the general characteristics of gorillas?
- The LARGEST extant primates
- Exclusively folivorous/herbivorous –therefore,
pretty BIG - Extreme sexual dimorphism
how much do male gorillas weigh? females?
- 400 pounds
- 150 pounds
when were gorillas first seen by outsiders?
500 BCE
- hanno the navigator thought they were really hairy people
what is the diet of gorillas?
- Exclusively folivorous/herbivorous = spend most of their time on the ground eating and resting –home ranges are between 3-15km2, but daily movements only around 500m (0.31 miles)
what is the social and mating system between gorillas?
harem, with some all-male troops
* Both males and females disperse at sexual maturity
* Silverback-female relationships are the most well developed
social relationships
what is the life history of gorillas?
Very long, slow life histories
what is the reproductive cycle of gorillas?
- Sexual maturity = 10-12 for females, and 11-13 for
males - Gestation = 8.5 months
- Females give birth every four years on average
- Infants wean at ~3 years of age
if gorillas do not have long-distance calls, how are conflicts resolved?
resolved visually –they have a ritualized, 9-step
charging display
(1) progressively quickening hooting,
(2) symbolic feeding,
(3) rising bipedally,
(4) throwing vegetation,
(5) chest-beating with cupped hands,
(6) one leg kick,
(7) sideways running, two-legged to four-legged,
(8) slapping and tearing vegetation, and
(9) thumping the ground with palms to end display.
where do orangutans live?
- Live exclusively in SE Asia (sometimes called the
Asian Great Ape)
what is the diet of the pongo?
Mainly frugivorous
how do pongo travel?
Completely arboreal and diurnal
what is the reproductive cycle of pongos?
Females maintain territories with dependent
young (up to 11 years!)
* Males wander around, overlapping female
ranges (Noyau)
what are the sexual dimorphism changes in male pongos?
- Males body mass 2x females
- Males 87 kg (191 lbs)
- Females 37kg (81.5 lbs)
unflanged male pongo
- Resemble females
(~ 40 kg) - Testes fully developed
“sneak and coerce” - Actively search for
females over a large
area - Forced copulations on
females who may or
may not be fertile
flanged male pongo
- Large (~ 80 kg)
- Fleshy throat sac and fatty
cheek pads - Long hair
“call and wait” - Produce long call to
attract females - Defend territory and
females (when possible)
what are the two species of chimpanzees?
- common chimpanzee
- bonobo chimpanzee
where do common chimpanzees live?
- africa
- one of the most ecologically flexible non-human ape
what is the diet of the common chimpanzee?
- Hundreds of plant species
- Fruit, leaves, seeds, flowers, cambium, pith, stems,
roots, wood, tubers, insects, meat (e.g., bush baby, red
colobus) - Ripe fruit = main part of diet
- Figs can be especially important (asynchronous)
what is the sexual dimorphism of common chimpanzees?
- Male body mass ~1.3 x greater
- Adult male 35-70 kg (75-155 lbs)
- Adult female 26-50 kg (57-110 lbs)
what is the social organization of the common chimpanzee?
- Fission-fusion (multi-male/multi-female communities)
- Stable membership
- Community members from ‘parties’
- ‘parties’ lack fixed membership
- Male philopatric/female dispersal
what is the mating system of common chimpanzees?
- Complex polygyandrous system
- Females develop sexual swellings
- Parous females = gain more interest from males
- High-ranked male restrict copulations of lower
ranked males - Male and female infanticide
what is the life history of common chimpanzees?
- Age at 1st reproduction b/t 13-14 yrs
- IBIs variable across pops.
- Gombe 3-5 yrs.
- Matings occur throughout the year
- Long infant dependence ~3 years total dependence
describe female-female relationships in common chimpanzees
- Female-female relationships are variable –some females
ignore each other, some have agonistic relationships, some
maintain long-term social bonds - Resident females are generally very agonistic to incoming
females - Males intervene- protect immigrants
decribe male-male relationships in common chimpanzees
- High rates of affiliative interactions
- Grooming more common among males
- Males compete for status/Linear dominance
- Commonly form short-term coalitions
- Some form long-term alliances
describe male-female relationships in common chimpanzees
- Mother-son bonds are very important, and
can have important fitness consequences for
males –females not seen to mate with their
brothers or fathers - Females will mate with multiple males,
showing distinct preference for higher
ranking males - Females will form “friendships” with lower
ranking males that can lead to copulation - Females in estrus will mate with multiple
males - During maximum tumescence, males will try
to maintain constant association with a
female, and high ranking males may try to
exclude lower ranking males from access
do common chimpanzees have intergroup relationships?
- Chimpanzees = very territorial
- Hostile relationship w/neighboring groups
- Males patrol territory- form patrols
- Patrols can be fatal - even to members inside the group!
where are bonobo chimpanzees found?
- Only found in the Democratic Republic of Congo
- Lowland evergreen tropical forest
- Also, drier forest & grassland habitat
what is the sexual dimorphism in the bonobo chimpanzee?
Less pronounced than in the other
great apes
Females average ~70 lbs, males
average ~85 lbs
what is the diet of the bonobo chimpanzee?
- Mainly frugivorous, but will
supplement diet with leaves,
small mammals, some monkeys
what is the social organization of bonobo?
- Fission - fusion community (same as common chimpanzee)
- Size can range from 20-100 (mixed-sex and age grps)
- Less pronounced dominance hierarchies
- Male philopatric/Female dispersal
what is the mating system of bonobo?
- Males mate multiple females (polygynously)
- Females mate promiscuously
- Females develop sexual swellings
- Swellings last longer than in common chimps
- More swelling cycles & receptive longer
what is the life history of bonobo?
- Age at 1st reproduction ~13 yrs
- IBI= ~4-6 yrs.
- No documented infanticide
describe female-female relationships in bonobo
- Low-moderate rates of affiliative interactions
- Females are not aggressive to immigrants
- New immigrants may have close relationship
w/resident females - High rates of sociosexual behavior –across all
age-sex classes
are their intergroup relationships in bonobo?
- Intergroup relationships = hostile
BUT… - No male patrols
- No incursions into neighboring territory
- No lethal coalitionary intergrp. Aggression
what is the mating strategies of humans?
- A study of 1,231 societies (The Ethnographic Atlas): 186 of 1,231 societies are socially monogamous (~15%), 1041 are polygynous/polygynandrous, 4 are polyandrous
- Sexual monogamy (based on paternity) is much lower
- Estimates of extra-pair paternity in monogamous contexts range from 0.8%-30%
what is the sexual dimorphism in homo sapiens?
- Humans have slight male-biased sexual dimorphism –human body size dimorphism by weight ~1.15, e.g. males are 15% bigger
- Compared to other primates, we are somewhere between the monogamous species (e.g., gibbons at 1.07) and polygynandrous species, (e.g., bonobos at 1.21, common chimps at 1.3)
- A general trend over the course of hominin evolution of reduced sexual dimorphism