Editing Chimpanzee (section)

===Group structure===
[[File:Chimpanzees in Uganda (5984913059).jpg|thumb|Group in Uganda]]
Chimpanzees live in communities that typically range from around 15 to more than 150 members but spend most of their time traveling in small, temporary groups consisting of a few individuals. These groups may consist of any combination of age and sexes. Both males and females sometimes travel alone.<ref name="behavior monographs">{{cite journal |last=Van Lawick-Goodall |first=J. |author-link=Jane Goodall |year=1968 |title=The behaviour of free-living chimpanzees in the Gombe Stream Reserve |journal=Animal Behaviour Monographs (Rutgers University) |volume=1 |issue=3 |page=167}}</ref> This [[fission–fusion society]] may include groups of four types: all-male, adult females and offspring, adults of both sexes, or one female and her offspring. These smaller groups emerge in a variety of types, for a variety of purposes. For example, an all-male troop may be organised to [[hunting|hunt]] for meat, while a group consisting of lactating females serves to act as a "nursery group" for the young.<ref name="Pepper"/>

At the core of social structures are males, which patrol the territory, protect group members, and search for food. Males remain in their natal communities, while females generally emigrate at adolescence. Males in a community are more likely to be related to one another than females are to each other. Among males, there is generally a dominance hierarchy, and males are dominant over females.<ref>{{cite journal |last1=Goldberg |first1=T. L. |last2=Wrangham |first2=R. W. |author2-link=Richard Wrangham |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> However, this unusual fission-fusion social structure, "in which portions of the parent group may on a regular basis separate from and then rejoin the rest,"{{sfn|Goodall|1986|p=147}} is highly variable in terms of which particular individual chimpanzees congregate at a given time. This is caused mainly by the large measure of individual autonomy that individuals have within their fission-fusion social groups.<ref name="Estes"/> As a result, individual chimpanzees often forage for food alone, or in smaller groups, as opposed to the much larger "parent" group, which encompasses all the chimpanzees which regularly come into contact with each other and congregate into parties in a particular area.<ref name="Pepper">{{cite journal |last1=Pepper |first1=J. W. |last2=Mitani |first2=J. C. |last3=Watts |first3=D. P. |year=1999 |title=General gregariousness and specific social preferences among wild chimpanzees |journal=International Journal of Primatology |volume=20 |issue=5 |pages=613–32 |doi=10.1023/A:1020760616641 |citeseerx=10.1.1.1000.4734|s2cid=25222840}}</ref>
[[File:013 Alpha male chimpanzee at Kibale forest National Park Photo by Giles Laurent.jpg|left|alt=Alpha male chimpanzee at Kibale National Park, Uganda|thumb|Alpha male chimpanzee at [[Kibale National Park]], Uganda.]]
Male chimpanzees exist in a linear [[dominance hierarchy]]. Top-ranking males tend to be aggressive even during dominance stability.<ref name="Muller2002">{{cite book |last=Muller |first=M. N. |date=2002 |chapter=Agonistic relations among Kanyawara chimpanzees |pages=112–124 |editor-last=Boesch |editor-first=C. |display-editors=etal |title=Behavioural Diversity in Chimpanzees and Bonobos |location=Cambridge |publisher=Cambridge University Press |isbn=0-521-00613-9}}</ref> This is probably due to the chimpanzee's fission-fusion society, with male chimpanzees leaving groups and returning after extended periods of time. With this, a dominant male is unsure if any "political maneuvering" has occurred in his absence and must re-establish his dominance. Thus, a large amount of aggression occurs within five to fifteen minutes after a reunion. During these encounters, displays of aggression are generally preferred over physical attacks.<ref name="Muller2002"/><ref name="Bygott1979">{{cite book |last=Bygott |first=J. D. |date=1979 |chapter=Agonistic behavior, dominance, and social structure in wild chimpanzees of the Gombe National Park |pages=73–121 |editor-last1=Hamburg |editor1-first=D. A. |editor-last2=McCown |editor-first2=E. R. |title=The Great Apes |location=Menlo Park |publisher=Benjamin-Cummings |isbn=978-0-8053-3669-6 |chapter-url=https://archive.org/details/greatapes0000unse_n7y7/page/73}}</ref>

Males maintain and improve their social ranks by forming coalitions, which have been characterised as "exploitative" and based on an individual's influence in agonistic interactions.<ref name="deWaal1987">{{cite book |last=de Waal |first=F. B. |author-link=Frans de Waal |date=1987 |chapter=Dynamic of social relationships |pages=421–429 |editor-last=Smuts |editor-first=B. B. |display-editors=etal |title=Primate Societies |location=Chicago |publisher=University of Chicago Press |isbn=978-0-226-76716-1}}</ref> Being in a coalition allows males to dominate a third individual when they could not by themselves, as politically apt chimpanzees can exert power over aggressive interactions regardless of their rank. Coalitions can also give an individual male the confidence to challenge a dominant or larger male. The more allies a male has, the better his chance of becoming dominant. However, most changes in hierarchical rank are caused by [[Dyad (sociology)|dyadic]] interactions.<ref name="Muller2002"/><ref name="Watts2001"/> Chimpanzee alliances can be very fickle, and one member may suddenly turn on another if it is to his advantage.<ref name="Nishida1986">{{cite book |last1=Nishida |first1=T. |last2=Hiraiwa-Hasegawa |first2=M. |date=1986 |chapter=Chimpanzees and bonobos: cooperative relationships among males |pages=165–177 |editor-last=Smuts |editor-first=B. B. |display-editors=etal |title=Primate Societies |location=Chicago and London |publisher=The University of Chicago Press |isbn=978-0-226-76716-1}}</ref>
[[File:Gombe Stream NP gegenseitiges Lausen.jpg|thumb|Mutual grooming, removing [[Louse|lice]]]]
Low-ranking males frequently switch sides in disputes between more dominant individuals. Low-ranking males benefit from an unstable hierarchy and often find increased sexual opportunities if a dispute or conflict occurs.<ref name="deWaal1987"/><ref name="Nishida1986"/> In addition, conflicts between dominant males cause them to focus on each other rather than the lower-ranking males. Social hierarchies among adult females tend to be weaker. Nevertheless, the status of an adult female may be important for her offspring.<ref name="Pusey1997"/> Females in [[Taï National Park|Taï]] have also been recorded to form alliances.<ref>{{cite book |author=Stumpf, R. |date=2007 |chapter=Chimpanzees and Bonobos: Diversity Within and Between Species |pages=321–344 |editor=Campbell C. J. |display-editors=etal |title=Primates in perspective |location=New York |publisher=Oxford University Press |isbn=978-0-19-539043-8}}</ref> While chimpanzee social structure is often referred to as [[patriarchal]], it is not entirely unheard of for females to forge coalitions against males.<ref>{{Cite journal |last=Newton-Fisher|first=N. E. |date=2006 |title=Female coalitions against male aggression in wild chimpanzees of the Budongo Forest |journal=International Journal of Primatology |volume=27 |issue=6 |pages=1589–1599 |doi=10.1007/s10764-006-9087-3 |s2cid=22066848 |issn=1573-8604}}</ref> There is also at least one recorded case of females securing a dominant position over males in their respective troop, albeit in a captive environment.<ref>{{Cite web |last=Wojci |first=A. |title=The rise and fall of a chimpanzee matriarchy |publisher=Przekrój Magazine |url=https://przekroj.pl/en/science/the-rise-and-fall-of-a-chimpanzee-matriarchy-agnieszka-wojci |access-date=18 August 2020 |website=[[Przekrój]] |date=20 October 2018 |language=en |archive-date=25 January 2021 |archive-url=https://web.archive.org/web/20210125213620/https://przekroj.pl/en/science/the-rise-and-fall-of-a-chimpanzee-matriarchy-agnieszka-wojci |url-status=live }}</ref> [[Social grooming]] appears to be important in the formation and maintenance of coalitions. It is more common among adult males than either between adult females or between males and females.<ref name="Watts2001">{{cite journal |author=Watts, D. P. |year=2001 |title=Reciprocity and interchange in the social relationships of wild male chimpanzees |journal=Behaviour |volume=139 |issue=2 |pages=343–370 |doi=10.1163/156853902760102708 |url=http://www2.unine.ch/repository/default/content/sites/ethol/files/shared/documents/watts_2002.pdf |archive-url=https://web.archive.org/web/20150421014820/http://www2.unine.ch/repository/default/content/sites/ethol/files/shared/documents/watts_2002.pdf |archive-date=2015-04-21 |url-status=live |citeseerx=10.1.1.516.3624}}</ref>
[[File:Adult male chimps in mahale.jpg|thumb|left |Males in Mahale National Park, Tanzania]]
Chimpanzees have been described as highly territorial and will frequently kill other chimpanzees,<ref>{{cite magazine |last=Walsh |first=B. |url=http://www.time.com/time/health/article/0,8599,1880229,00.html |archive-url=https://web.archive.org/web/20090219145829/http://www.time.com/time/health/article/0,8599,1880229,00.html |url-status=dead |archive-date=19 February 2009 |title=Why the Stamford chimp attacked |magazine=Time |date=18 February 2009 |access-date=6 June 2009}}</ref> although Margaret Power wrote in her 1991 book ''The Egalitarians'' that the field studies from which the aggressive data came, Gombe and Mahale, used artificial feeding systems that increased aggression in the chimpanzee populations studied. Thus, the behaviour may not reflect innate characteristics of the species as a whole.<ref name="Power.Anthropologist"/> In the years following her artificial feeding conditions at Gombe, Jane Goodall described groups of male chimpanzees patrolling the borders of their territory, brutally attacking chimpanzees that had split off from the Gombe group. A study published in 2010 found that the chimpanzees wage wars over territory, not mates.<ref>{{cite news |date=24 June 2010 |title=Killer instincts |newspaper=[[The Economist]] |url=https://www.economist.com/science-and-technology/2010/06/24/killer-instincts |url-access=registration |access-date=21 December 2023 |archive-date=21 December 2023 |archive-url=https://web.archive.org/web/20231221154203/https://www.economist.com/science-and-technology/2010/06/24/killer-instincts |url-status=live }}</ref> Patrols from smaller groups are more likely to avoid contact with their neighbours. Patrols from large groups even take over a smaller group's territory, gaining access to more resources, food, and females.<ref name="Nishida1986"/>{{sfn|Goodall|1986|pp=491, 528}} While it was traditionally accepted that only female chimpanzees immigrate and males remain in their natal troop for life, there are confirmed cases of adult males safely integrating themselves into new communities among West African chimpanzees, suggesting they are less territorial than other subspecies.<ref>{{Cite journal |last1=Sugiyama |first1=Y. |last2=Koman |first2=J. |date=1979 |title=Social structure and dynamics of wild chimpanzees at Bossou, Guinea |journal=Primates |volume=20 |issue=3 |pages=323–339 |doi=10.1007/BF02373387 |s2cid=9267686 |issn=1610-7365}}</ref>