Editing Primate (section)

===Social systems===
[[Richard Wrangham]] stated that [[Social structure|social systems]] of primates are best classified by the amount of movement by females occurring between groups.<ref name="social">{{cite book |author=Wrangham, R. W. |author-link=Richard Wrangham |chapter=Mutualism, kinship and social evolution |year=1982 |title=Current Problems in Sociobiology |publisher=Cambridge University Press |pages=269–89 |isbn=0-521-24203-7}}</ref> He proposed four categories:

* Female transfer systems&nbsp;– females move away from the group in which they were born. Females of a group will not be closely related whereas males will have remained with their natal groups, and this close association may be influential in social behavior. The groups formed are generally quite small.<ref name="social"/> This organization can be seen in [[chimpanzee]]s, where the males, who are typically related, will cooperate in defense of the group's territory.<ref>{{cite journal |author=Goldberg, T. L. |author2=Wrangham, R. W. | title=Genetic correlates of social behavior in wild chimpanzees: evidence from mitochondrial DNA | journal=Animal Behaviour | volume=54 | issue=3 | pages=559–70 | date=September 1997 | pmid=9299041 | doi=10.1006/anbe.1996.0450|s2cid=18223362 }}</ref> Evidence of this social system (called [[patrilocal residence]] when used by the [[Anthropology]]) has also been found among [[Neanderthal]] remains in [[Spain]]<ref>{{cite news | last = Bowdler | first = Neil | title = Neanderthal family found cannibalised in cave in Spain | url = https://www.bbc.co.uk/news/science-environment-12049854 | work = [[BBC News]] | date = 21 December 2010}}</ref> and in remains of ''[[Australopithecus]]'' and ''[[Paranthropus robustus]]'' groups in southern Africa.<ref name="CavewomenBBC2011">{{cite news | first=Neil | last=Bowdler | url=https://www.bbc.co.uk/news/science-environment-13609260 | title=Ancient cave women 'left childhood homes' | date=2 June 2011 | work=[[BBC News]] | access-date=2 June 2011}}</ref><ref name="Copeland2011">{{cite journal | last1 = Copeland | first1 = Sandi R.  |display-authors=etal|title=Strontium isotope evidence for landscape use by early hominins  |volume=474 | issue = 7349 | date=1 June 2011 |pages=76–78 |journal=Nature |doi=10.1038/nature10149 |pmid=21637256| s2cid = 205225222 }}</ref> Among New World Monkeys, [[spider monkey]]s and [[muriqui]]s use this system.<ref>{{cite book|title=Primates in Perspective|author1=Fiore, A. D. |author2=Campbell, C. J. |name-list-style=amp |chapter=The Atelines|year=2007|page=175|publisher=Oxford University Press|editor=Campbell, C. J. |editor2=Fuentes, A. |editor3=MacKinnon, K. C. |editor4=Panger, M. |editor5=Bearder, S. K.|isbn=978-0-19-517133-4}}</ref>
[[File:Ringstaartmakis - Ring-tailed Lemur.jpg|thumb|right|A social huddle of [[ring-tailed lemur]]s. The two individuals on the right exposing their white ventral surface are sunning themselves.]]
* Male transfer systems&nbsp;– while the females remain in their natal groups, the males will emigrate as adolescents. Group sizes are usually larger.<ref name="social"/> This system is common among the [[ring-tailed lemur]], [[capuchin monkey]]s and [[Cercopithecinae|cercopithecine monkeys]].<ref name="Strier2007" />
* Monogamous species&nbsp;– a male–female bond, sometimes accompanied by a juvenile offspring. There is shared responsibility of parental care and territorial defense. The offspring leaves the parents' territory during adolescence.<ref name="social"/> [[Indri]], [[lariang tarsier]]s, [[Callitrichidae]] monkeys and gibbons use this system, although "monogamy" in this context does not necessarily mean absolute sexual fidelity.<ref>{{cite book|title=Primates in Perspective|author=Bartlett, T. Q.|chapter=The Hylobatidae|year=2007|editor=Campbell, C. J. |editor2=Fuentes, A. |editor3=MacKinnon, K. C. |editor4=Panger, M. |editor5=Bearder, S. K.|publisher=Oxford University Press|isbn=978-0-19-517133-4|page=283}}</ref><ref name=Dixon/> These species do not live in larger groups.
* Solitary species&nbsp;– males and females live in overlapping home ranges.<ref name="social"/><ref name=Dixon/> This type of organization is found in lorises, galagos, [[mouse lemur]]s, aye-ayes and orangutans.<ref name=Dixon/>

Other systems are known to occur as well. For example, with [[howler monkey]]s and [[gorilla]]s both the males and females typically transfer from their natal group on reaching sexual maturity, resulting in groups in which neither the males nor females are typically related.<ref name="Sussman2003" /><ref name="Watts 1996">{{Cite book|author=Watts D. P.|year=1996|contribution=Comparative socio-ecology of gorillas|editor1=McGrew W. C. |editor2=Marchant L. F. |editor3=Nishida, T.|title=Great Ape Societies|url=https://archive.org/details/greatapesocietie00mcgr|location=Cambridge (England|publisher=Cambridge Univ Press|pages=[https://archive.org/details/greatapesocietie00mcgr/page/16 16]–28|isbn=978-0521555364}}</ref> Some prosimians, [[Colobinae|colobine]] monkeys and [[Callitrichinae|callitrichid]] monkeys also use this system.<ref name="Strier2007" />

The transfer of females or males from their native group is likely an adaptation for avoiding inbreeding.<ref name=Charpentier>{{cite journal |vauthors=Charpentier MJ, Widdig A, Alberts SC |title=Inbreeding depression in non-human primates: a historical review of methods used and empirical data |journal=American Journal of Primatology |volume=69 |issue=12 |pages=1370–86 |date=December 2007 |pmid=17486606 |doi=10.1002/ajp.20445 |s2cid=46626761 |url=https://hal.archives-ouvertes.fr/hal-02079454 }}</ref> An analysis of breeding records of captive primate colonies representing numerous different species indicates that the infant mortality of inbred young is generally higher than that of non-inbred young.<ref name=Charpentier /><ref>{{cite journal | vauthors = Ralls K, Ballou J | year = 1982 | title = Effect of inbreeding on infant mortality in captive primates | doi = 10.1007/BF02693747 | journal = International Journal of Primatology | volume = 3 | issue = 4 | pages = 491–505 | s2cid = 10954608 | url = http://si-pddr.si.edu/dspace/bitstream/10088/6162/1/8133A167-A994-450A-ADF4-DAD3F4EAA6F6.pdf }}{{Dead link|date=October 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> This effect of inbreeding on infant mortality is probably largely a result of increased expression of deleterious recessive alleles (see [[Inbreeding depression]]).
[[File:Three chimpanzees with apple.jpg|thumb|right|[[Chimpanzee]]s are social great apes.]]
Primatologist [[Jane Goodall]], who studied in the [[Gombe Stream National Park]], noted [[fission-fusion society|fission-fusion societies]] in chimpanzees.<ref>{{cite journal |last1=Constable |first1=J. L. |last2=Ashley |first2=M. V. |last3=Goodall |first3=J. |last4=Pusey |first4=A. E. |title=Noninvasive paternity assignment in Gombe chimpanzees |url=https://archive.org/details/sim_molecular-ecology_2001-05_10_5/page/1279 |journal=Molecular Ecology |volume=10 |issue=5 |pages=1279–300 | date=May 2001 |pmid=11380884 |doi=10.1046/j.1365-294X.2001.01262.x|bibcode=2001MolEc..10.1279C |s2cid=46604532 }}</ref> There is ''fission'' when the main group splits up to forage during the day, then ''fusion'' when the group returns at night to sleep as a group. This social structure can also be observed in the [[hamadryas baboon]],<ref name="Rowe1996">{{cite book|title=The Pictorial Guide to the Living Primates|url=https://archive.org/details/pictorialguideto0000rowe|url-access=registration|author=Rowe, N.|year=1996|publisher=Pogonias Press|isbn=0-9648825-0-7|pages=[https://archive.org/details/pictorialguideto0000rowe/page/n15 4], 139, 143, 15 185, 223}}</ref> [[spider monkey]]s<ref name="Sussman2003" /> and the [[bonobo]].<ref name="Rowe1996" /> The [[gelada]] has a similar social structure in which many smaller groups come together to form temporary herds of up to 600 monkeys.<ref name="Rowe1996" /> [[Human]]s also form fission-fusion societies. In hunter-gatherer societies, humans form groups which are made up of several individuals that may split up to obtain different resources.<ref>{{Cite journal|last1=Couzin|first1=Iain D.|last2=Laidre|first2=Mark E.|date=August 2009|title=Fission–fusion populations|journal=Current Biology|volume=19|issue=15|pages=R633–R635|doi=10.1016/j.cub.2009.05.034|pmid=19674541|s2cid=13549970|issn=0960-9822|doi-access=free|bibcode=2009CBio...19.R633C }}</ref>

These social systems are affected by three main ecological factors: distribution of resources, [[Group size measures|group size]], and [[predation]].<ref name="vertlife">{{cite book |last1=Pough |first1=F. W. |last2=Janis |first2=C. M. |last3=Heiser |first3=J. B. |title=Vertebrate Life |url=https://archive.org/details/vertebratelife0000poug |chapter=Primate Societies |year=2005 |orig-year=1979 |edition=7th |publisher= Pearson |pages=[https://archive.org/details/vertebratelife0000poug/page/621 621]–623 |isbn=0-13-127836-3}}</ref> Within a social group there is a balance between cooperation and competition. Cooperative behaviors in many primates species include [[social grooming]] (removing [[Parasitism|skin parasites]] and cleaning wounds), food sharing, and collective defense against predators or of a territory. Aggressive behaviors often signal competition for food, sleeping sites or mates. Aggression is also used in establishing [[dominance hierarchy|dominance hierarchies]].<ref name="vertlife" /><ref>[[Barbara Smuts|Smuts, B.B.]], Cheney, D.L. Seyfarth, R.M., Wrangham, R.W., & Struhsaker, T.T. (Eds.) (1987). ''Primate Societies''. Chicago: University of Chicago Press for articles on the structure and function of various primate societies.</ref>

In November 2023, scientists reported, for the first time, evidence that groups of primates, particularly [[bonobo]]s, are capable of cooperating with each other.<ref name="NYT-20231116">{{cite news |last=Zimmer |first=Carl |authorlink=Carl Zimmer |title=Scientists Find First Evidence That Groups of Apes Cooperate - Some bonobos are challenging the notion that humans are the only primates capable of group-to-group alliances. |url=https://www.nytimes.com/2023/11/16/science/bonobos-cooperation-study.html |date=16 November 2023 |work=[[The New York Times]] |url-status=live |archiveurl=https://archive.today/20231116194259/https://www.nytimes.com/2023/11/16/science/bonobos-cooperation-study.html |archivedate=16 November 2023 |accessdate=17 November 2023 }}</ref><ref name="SCI-20231116">{{cite journal |author=Samuni, Liran |display-authors=et al. |title=Cooperation across social borders in bonobos
|url=https://www.science.org/doi/10.1126/science.adg0844 |date=16 November 2023 |journal=[[Science (journal)|Science]] |volume=382 |issue=6672 |pages=805–809 |doi=10.1126/science.adg0844 |pmid=37972165 |bibcode=2023Sci...382..805S |url-status=live |archiveurl=https://archive.today/20231117125744/https://www.science.org/doi/10.1126/science.adg0844 |archivedate=17 November 2023 |accessdate=17 November 2023 }}</ref>