Monogamy Flashcards
examples of monogamy in primates
gibbons!
case study
sommer-reichard 1999: white handed gibbons in thailand
traditional view of monogamy
male + female + offspring:
- strict territortality
- pair formation by natal dispersal
- life long mongaomy
- monogamy exclusivity
- nuclear familities
- pairbonded
revised view of monogamy in gibbons
not 100% monogamous (just pair-bonded)but
- extracopulations occur
- divorces occur
what are gibbon social structures driven by
female resource compeititon (CONTEST; are fruit eaters)
hypothesis of mongamy in primates
- male mate guarding technique
a. improve own reproductive success
b. prevent extra-copulation
c. paternity certainity - infanticide protection
- for secondary paternal care
most probably theory of mongamy
reduce infanticide= allow extended developmental period of child crucial for big brains
primatologists studying monogamy
opie 2013
when is monogamy likely to devvelop
when males can defend patches with equaly quality of resources (food, shelter, etc) meaning mate guarding is easier as environmental reasons doesnt influence female choice
how do male gibbons guard their mates
remain in proximity
chase away others
attract females (by parental investment)
hypothesis of monogamy in mammals
- male to male mate guarrding strategy
- infanticide protection
- secondary paternal care
origins of mongamy
long lactation periods due to altricial infants= need more protection= need more bi-parental care to speed up lcation and reduce infanticide
hence; polygyandry—> social monogamy evolved
dispersal effect on mongamy
if females occupy small areas and are dispresed from one another; hard for males to monopolize all of them= hence just guard ONE
most probably theory for mongamy according to opie
infanticide risks; mongamy stops this which allows for extended brain development
female pros of monogamy
ally for food access
infant care= increased own RS
defense
security
where are the gibbons
in Khao Yai (thainland rainforest)
traditional view of gibbon social structures
- livei n nuclear familes
- breeding pair are lifelong sexually monogamous
- are territorial
- they sing to defent territort
- dueting functions to strengthen pair bond
revision of gibbon social structures
- group ranges overlap so mutual territory not exclusive
- partners changes/epc exist
- Dueting/singing functions as a way for females to advertise themselves and males to say that they are taken
competing hypothesis for monogamy
- guarding against infanticide
- mate guarding
- reduce predation risk
- defend an exclusive rsource
- biparental care
conditions of guarding against infanticide hypothesis
- no strict sesaonltiy
- long birth intereveals/lactiaonal ammherorea casued by altriciality
- young not hidden in nests
evidence for infanticide-monogamy hypothesis (opie)
- dueting: dissccourages strange males to trespass
- absence of mate; female will stop calling when shes vulnerable to infanticide
- females wary of male intruders= less willing to get involved in terrotirial encounters if they had an infant or not
- high male infanticide is the onlt trait to consisstent precede apperance of social monogamy, as both parents need to be there to defened child and shortened lacation reduces infanticide likehilood (opie 2013)
evidence against infanticide hypothesis (sommer and Reichard)
- gibbons= calling sometimes transforms into triot with immature males/females (sommer, reichard)
- duetting= might be a way to check for male fitness rahter than reinforce monogamy
mate guarding hypothesis explanation
males= cant defend a large enough area to encompass the range of more than one female
caused by female dispersion due to/and resource competition
predator risk hypothesis explanation
male vigiliance allows mates to concentrate on feeding= thus more offspring are produced (RS increases)
resource defense hypothesis explanation
male defends territory against other individuasl for female
bi parental care hypothesis explanation
if high costs of raiing offspring= females need extra help
new world primates; tamarins and marmosets
mate guarding hypothesis evidence against
Shaik and Dunbar: gibbon males help gain more conceptions if they opt to just find as many females as possible (EPC)
predator risk hypothesis evidence against
differences in feeding times between males and females insgifiancant
resource defense hypothesis evidence against
- territortires might overlap
- territories dont decrease in size after male death (shaik and dunbar 1990)
- gibbons exhibit all characteristics of non territorial primates
bi parental care hypothesis evidence against
paternal care follows apperance of social monogamy rather than preceding it: as not all socially monogamous mammals have it (opie 2013)
