Editing Primate (section)

===Mating systems===
{{Multiple image |align= right |direction=vertical |image1=SAGUI-DE-TUFOS-BRANCOS.jpg|caption1=Two [[common marmoset]]s, the species lives in monogamous pairs|image2=Gelada group.jpg|caption2=[[Gelada]] harem: one male and multiple females}}
The [[mating system]]s of primates vary between [[Monogamy in animals|monogamy]], [[Polyandry in animals|polyandry]], [[Polygyny in animals|polygyny]] and [[polygynandry]]. In monogamous species, adult males and females form long-lasting [[pair bond]]s. Compared to other systems, there is little competition for mating rights and males and females tend to be similar in size. Polyandry, which involves groups consisting of single females mating with multiple males, may arise as a secondary mating system in monogamous species. In the [[brown-mantled tamarin]], a female may breeding with one or two males. Polyandry may have developed due to the high frequency of twin births, which require more help in raising.<ref name=Dixon>{{cite book|author=Dixon, Alan F|year=2012|title=Primate Sexuality|publisher=Oxford University Press|pages=32–61|isbn=9780199544646}}</ref> 

Polygynous species include gorillas, [[Northern plains gray langur|Hanuman langur]]s, geladas, hamadryas baboons, [[proboscis monkey]]s, and [[golden snub-nosed monkey]]s, and consists of one male mating with multiple females within a [[Harem (zoology)|harem]] or one-male unit. Sexual dimorphism tends to be higher in these species and males may also develop prominent [[secondary sex characteristic]]s. In the patriarchal hamadryas baboon, the males aggressively herd females into their groups and violently discipline those that wander. By contrast, in gelada society, which is based on female kinship, a male is dependent on the support of the females in his unit and cannot impose on them. Polygynous males must defend their harems from rivals, who may try to take over.<ref name=Dixon/>

In some species, such as ring-tailed lemurs, [[sifaka]]s, [[macaque]]s, most [[baboon]]s, [[mangabey]]s, [[squirrel monkey]]s, [[woolly monkey]]s, spider monkeys, [[woolly spider monkey]]s, chimpanzees and bonobos, both males and females mate with multiple partners. Polygynandry occurs in [[Multi-male group|multimale-multifemale groups]], and since females mate many times before conception, males have large testicles for [[sperm competition]]. Males may exist in a [[dominance hierarchy]] and those at the top will try to monopolize access to the females. Consortships may occur in some species but these are short-term. In solitary-living species, males and females mate with partners whose home ranges they overlap with. This is known as a 'dispersed' mating system.<ref name=Dixon/>

Genetic evidence indicates that humans were predominantly [[Polygyny|polygynous]] for most of their existence as a species, but that this began to shift during the Neolithic, when [[monogamy]] started becoming widespread concomitantly with the transition from nomadic to sedentary societies.<ref>{{Cite journal |last1=Dupanloup |first1=Isabelle |last2=Pereira |first2=Luisa |last3=Bertorelle |first3=Giorgio |last4=Calafell |first4=Francesc |last5=Prata |first5=Maria João |last6=Amorim |first6=Antonio |last7=Barbujani |first7=Guido |date=1 July 2003 |title=A Recent Shift from Polygyny to Monogamy in Humans Is Suggested by the Analysis of Worldwide Y-Chromosome Diversity |url=http://link.springer.com/10.1007/s00239-003-2458-x |journal=[[Journal of Molecular Evolution]] |volume=57 |issue=1 |pages=85–97 |doi=10.1007/s00239-003-2458-x |pmid=12962309 |bibcode=2003JMolE..57...85D |issn=0022-2844 |access-date=13 July 2024 |via=Springer Link}}</ref> Most modern human societies consist of monogamous [[marriage]]s, but allow for polygyny, particularly for those of a high status.<ref name=Dixon/>