In conclusion, there are 3 scenarios that may lead to Polygyny:

(1) Females have no other choice but to mate with a mated male

(2) Females may be deceived

(3) Males control access to resources, but also Females may actively assess the consequences of their decisions and make an adaptive choice

....let’s examine this relationship between resources and females more closely in mammals....

Understanding variation in Mammalian mating systems is best understood in terms of what leads to a high or low POLYGYNY potential

E.g., Female reproductive success is limited by access to resources, thus the distribution of females depends on resource dispersion

(1) If females are clumped in space or predictable in time there is a higher POLYGYNY potential than if not clumped or predictable

(2) If males can defend a territory or access to females either directly or indirectly viacompetition for resource rich sites there is a higher POLYGYNY potential than if defense is not possible

A Comparative Survey of Mating Systems in Mammals

Even distribution of resources, little polygamy potential

Patchy distribution of resources, high polygamy potential

Females solitary and range defensible by males: In 60% of mammalian species the female is solitary and the male defends a territory that overlaps one or more female ranges

- If female ranges are small relative to the area a male can defend – polygyny - If female ................ large ............................................................ - monogamy

In the latter, usually the male deserts after mating, but in ~3% they stay to give parental care.

African wild dogs – coop. hunting, feedingKlipspringer - defense

Marmosetscarry young

Females solitary and range not defensible by males: Temporary, and wandering, association during estrus - monogamous

MooseOrangutan

Females social and range defensible by males:Can lead to permanent harem attached to male’s territory

Hanuman langurs

Colobus monkeys

Several males (often relatives) may defend larger groups more successfully and increase length of tenure of a harem

Females social, range not defensible,but Female movements are predictable:Males defend small ranges and wait for females to pass through on the way to predictable routes...

...on the way to the waterhole...

...or to richfeedinggrounds

Females social, range not defensible,Female movements not predictableMales follow females

Elephants – small female groups

Seasonal Harems

Seasonal estrus (predictability in time) – allows males to build up energy reserves for mating season and aggressively defend harems for the one month females are fertile.

Permanent Harems when females do not all come into estrus at the same time(unpredictability) –

solitary social

defensible range

non-defensible

small: Monolarge: Polygyny

Monogamy

Polygyny(harems)

Summary: in mammals, mating systems are determined from the complex relationshipsbetween female range size, movement, sociality, predictability in time and space, andthe male’s ability to defend a range

Polygyny of various sorts (including harems) depending on predictability of female movement and estrus

♀ = 5.0

♂ = 5.0

♀ = 6.7

♂ = 3.7

♂β = 3.0

♀ = 3.8

♀β = 3.8

♂ = 7.6

Lastly, multiple mating systems can occur withina single species, sometimes driven by environmentalcircumstances