View source for Chimpanzee

{{Short description|Species of great ape}}
{{redirect|Chimp|other uses|Chimpanzee (disambiguation)|and|Chimp (disambiguation)}}
{{pp-semi-indef|small=yes}}
{{Good article}}
{{Use dmy dates|date=January 2019}}
{{Speciesbox
| fossil_range = {{fossilrange|4|0|earliest=6}}<ref name="McBrearty Jablonski 2005 pp. 105–108">{{cite journal |last1=McBrearty |first1=S. |last2=Jablonski |first2=N. G. |title=First fossil chimpanzee |journal=Nature |volume=437 |issue=7055 |year=2005 |issn=0028-0836 |doi=10.1038/nature04008 |pmid=16136135 |pages=105–108 |bibcode=2005Natur.437..105M |s2cid=4423286}}</ref>
| status = EN
| status_system = IUCN3.1
| status_ref = <ref name="iucn">{{cite iucn |last1=Humle |first1=T. |last2=Maisels |first2=F. |last3=Oates |first3=J. F. |last4=Plumptre |first4=A. |last5=Williamson |first5=E. A. |year=2016 |title=''Pan troglodytes'' |errata=2018 |volume=2016 |page=e.T15933A129038584 |doi=10.2305/IUCN.UK.2016-2.RLTS.T15933A17964454.en |access-date=8 August 2021}}</ref>
| status2 = CITES_A1
| status2_system = CITES
| status2_ref = <ref name= "CITES">{{Cite web|title=Appendices {{!}} CITES|url=https://cites.org/eng/app/appendices.php|access-date=2022-01-14|website=cites.org|archive-date=5 December 2017|archive-url=https://web.archive.org/web/20171205014647/https://cites.org/eng/app/appendices.php|url-status=live}}</ref>
| image = 015 Chimpanzee at Kibale forest National Park Photo by Giles Laurent.jpg
| image_caption = [[Eastern chimpanzee]] in [[Kibale National Park]], Uganda
| genus = Pan
| species = troglodytes
| authority = ([[Johann Friedrich Blumenbach|Blumenbach]], 1775)
| range_map = Pan troglodytes area.png
| range_map_caption = Distribution of subspecies
{{legend|#3fc071|''Pan troglodytes verus''}}
{{legend|#c5bdbd|''P. t. ellioti''}}
{{legend|#d58780|''P. t. troglodytes''}}
{{legend|#87bddf|''P. t. schweinfurthii''}}
| subdivision = {{blist
  | ''[[Pan troglodytes verus|P. t. verus]]''
  | ''[[Pan troglodytes ellioti|P. t. ellioti]]''
  | ''[[Pan troglodytes troglodytes|P. t. troglodytes]]''
  | ''[[Pan troglodytes schweinfurthii|P. t. schweinfurthii]]''
  }}
| synonyms = {{blist
  |''[[Simia]] troglodytes'' <small>[[Johann Friedrich Blumenbach|Blumenbach]], 1775</small>
  |''Troglodytes troglodytes'' <small>(Blumenbach, 1776)</small>
  |''Troglodytes niger'' <small>[[Étienne Geoffroy Saint-Hilaire|E. Geoffroy]], 1812</small>
  |''Pan niger'' <small>(E. Geoffroy, 1812)</small>
  |''Anthropopithecus troglodytes'' <small>([[John Bland-Sutton|Sutton]], 1883)</small>}}
}}

The '''chimpanzee''' ({{IPAc-en|tʃ|ɪ|m|p|æ|n|ˈ|z|i}}; '''''Pan troglodytes'''''), also simply known as the '''chimp''', is a species of [[Hominidae|great ape]] native to the forests and savannahs of [[tropical Africa]]. It has four confirmed subspecies and a fifth proposed one. When its close relative the [[bonobo]] was more commonly known as the pygmy chimpanzee, this species was often called the '''common chimpanzee''' or the '''robust chimpanzee'''. The chimpanzee and the bonobo are the only species in the genus [[Pan (genus)|''Pan'']]. Evidence from fossils and DNA sequencing shows that ''Pan'' is a [[sister taxon]] to the [[Human evolution|human lineage]] and is thus [[human]]s' closest living relative.

The chimpanzee is covered in coarse black hair but has a bare face, fingers, toes, palms of the hands, and soles of the feet. It is larger and more robust than the bonobo, weighing {{cvt|40|–|70|kg}} for males and {{cvt|27|–|50|kg}} for females and standing {{cvt|150|cm|ftin|0}}.

The chimpanzee lives in groups that range in size from 15 to 150 members, although individuals travel and forage in much smaller groups during the day. The species lives in a strict male-dominated hierarchy, where disputes are generally settled without the need for violence. Nearly all chimpanzee populations have been recorded [[Tool use by animals|using tools]], modifying sticks, rocks, grass and leaves and using them for [[hunting]] and acquiring [[honey]], [[termite]]s, [[ant]]s, nuts and water. The species has also been found creating sharpened sticks to spear small mammals. Its [[pregnancy|gestation]] period is eight months. The infant is weaned at about three years old but usually maintains a close relationship with its mother for several years more.

The chimpanzee is listed on the [[IUCN Red List]] as an [[endangered]] species. Between 170,000 and 300,000 individuals are estimated across its range. The biggest threats to the chimpanzee are habitat loss, poaching, and disease. Chimpanzees appear in Western popular culture as stereotyped clown-figures and have featured in entertainments such as [[chimpanzees' tea party|chimpanzees' tea parties]], circus acts and stage shows. Although chimpanzees have been kept as pets, their strength, aggressiveness, and unpredictability makes them dangerous in this role. Some hundreds have been kept in laboratories for research, especially in the United States. Many attempts have been made to teach languages such as [[American Sign Language]] to chimpanzees, with limited success.

==Etymology==
[[File:Yousaf et al. 2021 Fig.1.svg|thumb|Taxnomic tree of apes, based on genome sequencing by The Chimpanzee Sequencing and Analysis Consortium. Figure from Yousaf et al. 2021,<ref>{{Cite journal|last1=Yousaf|first1=Aisha|last2=Liu|first2=Junfeng|last3=Ye|first3=Sicheng|last4=Chen|first4=Hua|date=2021|title=Current Progress in Evolutionary Comparative Genomics of Great Apes|journal=Frontiers in Genetics|volume=12|pages=1436|doi=10.3389/fgene.2021.657468| pmc=8385753 |pmid=34456962|issn=1664-8021|doi-access=free}}</ref> adapted from Prado-Martinez et al. 2013.<ref>{{Cite journal|last1=Prado-Martinez|first1=Javier|last2=Sudmant|first2=Peter H.|last3=Kidd|first3=Jeffrey M.|last4=Li|first4=Heng|last5=Kelley|first5=Joanna L.|last6=Lorente-Galdos|first6=Belen|last7=Veeramah|first7=Krishna R.|last8=Woerner|first8=August E.|last9=O'Connor|first9=Timothy D.|last10=Santpere|first10=Gabriel|last11=Cagan|first11=Alexander|date=July 2013|title=Great ape genetic diversity and population history|journal=Nature|language=en|volume=499|issue=7459|pages=471–475|doi=10.1038/nature12228|pmid=23823723|pmc=3822165|bibcode=2013Natur.499..471P|issn=1476-4687}}</ref>]]
The English word ''chimpanzee'' is first recorded in 1738.<ref>{{cite web |title=chimpanzee |url=https://www.dictionary.com/browse/chimpanzee |publisher=Dictionary.reference.com |access-date=18 May 2019 |archive-date=18 May 2019 |archive-url=https://web.archive.org/web/20190518163608/https://www.dictionary.com/browse/chimpanzee |url-status=live }}</ref> It is derived from [[Vili language|Vili]] ''ci-mpenze''<ref>{{cite book |title=American Heritage Dictionary |date=2011 |edition=5th |chapter-url=https://www.ahdictionary.com/word/search.html?q=chimpanzee |access-date=31 August 2018 |chapter=chimpanzee |publisher=Houghton Mifflin Harcourt Publishing Company |archive-date=1 September 2018 |archive-url=https://web.archive.org/web/20180901113224/https://www.ahdictionary.com/word/search.html?q=chimpanzee |url-status=live }}</ref> or [[Tshiluba language]] ''chimpenze'', with a meaning of "[[ape]]",<ref>{{cite web |title=chimpanzee |url=https://www.etymonline.com/word/chimpanzee#etymonline_v_11268 |website=Online Etymology Dictionary |access-date=31 August 2018 |archive-date=16 December 2019 |archive-url=https://web.archive.org/web/20191216194133/https://www.etymonline.com/word/chimpanzee#etymonline_v_11268 |url-status=live }}</ref> or "mockman".<ref>{{cite book|editor=Hastrup, Kirsten|year=2013|title=Anthropology and Nature|publisher=Taylor & Francis|page=168|isbn=9781134463213}}</ref> The colloquialism "chimp" was most likely coined some time in the late 1870s.<ref>{{cite web |url=http://dictionary.reference.com/browse/chimp |title=chimp definition &#124; Dictionary.com |publisher=Dictionary.reference.com |access-date=6 June 2009 |archive-date=3 March 2016 |archive-url=https://web.archive.org/web/20160303170009/http://dictionary.reference.com/browse/chimp |url-status=live }}</ref> The genus name ''Pan'' derives from the [[Pan (god)|Greek god]], while the [[Specific name (zoology)|specific name]] ''troglodytes'' was taken from the [[Troglodytae]], a mythical race of cave-dwellers.<ref name="Corbey"/><ref name="Stanford"/>

==Taxonomy==
The first great ape known to Western science in the 17th century was the "[[Bornean orangutan|orang-outang]]" (genus ''Pongo''), the local [[Malay language|Malay]] name being recorded in Java by the Dutch physician [[Jacobus Bontius]]. In 1641, the Dutch anatomist [[Nicolaes Tulp]] applied the name to a chimpanzee or bonobo brought to the Netherlands from Angola.<ref name="van WyheKjærgaard2015">{{cite journal |last1=van Wyhe |first1=J. |last2=Kjærgaard |first2=P. C. |title=Going the whole orang: Darwin, Wallace and the natural history of orangutans |journal=Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences |volume=51 |year=2015 |pages=53–63 |doi=10.1016/j.shpsc.2015.02.006 |pmid=25861859 |doi-access=free}}</ref> Another Dutch anatomist, [[Peter Camper]], dissected specimens from Central Africa and Southeast Asia in the 1770s, noting the differences between the African and Asian apes. The German naturalist [[Johann Friedrich Blumenbach]] classified the chimpanzee as ''Simia troglodytes'' by 1775. Another German naturalist, [[Lorenz Oken]], coined the genus ''Pan'' in 1816. The bonobo was recognised as distinct from the chimpanzee by 1933.<ref name="Corbey">{{cite book |last=Corbey |first=R. |year=2005 |title=The Metaphysics of Apes: Negotiating the Animal-Human Boundary |publisher=Cambridge University Press |pages=42–51 |isbn=978-0-521-83683-8}}</ref><ref name="Stanford">{{cite book |last=Stanford |first=C. |year=2018 |title=The New Chimpanzee, A Twenty-First-Century Portrait of Our Closest Kin |publisher=Harvard University Press |pages=176 |isbn=978-0-674-97711-2}}</ref><ref name="Jones_etal.1996">{{cite journal |last1=Jones |first1=C. |last2=Jones |first2=C. A. |last3=Jones |first3=K. |last4=Wilson |first4=D. E. |author4-link=Don E. Wilson |year=1996 |title=''Pan troglodytes'' |journal=Mammalian Species |issue=529 |pages=1–9 |doi=10.2307/3504299 |jstor=3504299 |doi-access=free}}</ref>

===Evolution===
{{further |Chimpanzee–human last common ancestor}}
Despite a large number of ''[[Homo]]'' fossil finds, ''Pan'' fossils were not described until 2005. Existing chimpanzee populations in West and Central Africa do not overlap with the major [[human fossil]] sites in East Africa, but chimpanzee fossils have now been reported from Kenya. This indicates that both humans and members of the ''Pan'' [[clade]] were present in the [[East African Rift]] Valley during the [[Middle Pleistocene]].<ref name="McBrearty2005">{{cite journal |last1=McBrearty |first1=S. |last2=Jablonski |first2=N. G. |date=September 2005 |title=First fossil chimpanzee |journal=Nature |pmid=16136135 |doi=10.1038/nature04008 |bibcode=2005Natur.437..105M |volume=437 |issue=7055 |pages=105–8|s2cid=4423286}}</ref>

According to studies published in 2017 by researchers at [[George Washington University]], bonobos, along with chimpanzees, split from the human line about 8 million years ago; then bonobos split from the common chimpanzee line about 2 million years ago.<ref name="GWU-20170505">{{cite news |author=Staff |title=Bonobos May Resemble Humans More Than You Think - A GW researcher examined a great ape species' muscles and found they are more closely related to humans than common chimpanzees. |url=https://gwtoday.gwu.edu/bonobos-may-resemble-humans-more-you-think |date=5 May 2017 |work=[[George Washington University]] |url-status=live |archiveurl=https://archive.today/20230414135148/https://gwtoday.gwu.edu/bonobos-may-resemble-humans-more-you-think |archivedate=14 April 2023 |accessdate=14 April 2023 }}</ref><ref name="SR-20170404">{{cite journal |last1=Diogo |first1=Rui |last2=Molnar |first2=Julia L. |last3=Wood |first3=Bernard |title=Bonobo anatomy reveals stasis and mosaicism in chimpanzee evolution, and supports bonobos as the most appropriate extant model for the common ancestor of chimpanzees and humans |journal=[[Scientific Reports]] |date=2017 |volume=7 |number=608 |page=608 |doi=10.1038/s41598-017-00548-3 |pmid=28377592 |pmc=5428693 |bibcode=2017NatSR...7..608D }}</ref> Another 2017 genetic study suggests ancient gene flow ([[introgression]]) between 200,000 and 550,000 years ago from the bonobo into the ancestors of central and eastern chimpanzees.<ref name="de Manuel 2016">{{cite journal |last1=de Manuel |first1=M. |first2=M. |last2=Kuhlwilm |last3=P. |first3=Frandsen|display-authors=etal |title=Chimpanzee genomic diversity reveals ancient admixture with bonobos |journal=Science |volume=354 |issue=6311 |pages=477–481 |date=October 2016 |pmid=27789843 |pmc=5546212 |doi=10.1126/science.aag2602 |bibcode=2016Sci...354..477D}}</ref>

===Subspecies and population status===
Four [[subspecies]] of the chimpanzee have been recognised,<ref name="Groves, Colin 2001 pp. 303-307">{{cite book |last=Groves |first=C. P. |author-link=Colin Groves |year=2001 |title=Primate Taxonomy |pages=303–307 |location=Washington, DC |publisher=Smithsonian Institution Press |isbn=978-1-56098-872-4}}</ref><ref>{{cite book |last1=Hof |first1=J. |last2=Sommer |first2=V. |title=Apes Like Us: Portraits of a Kinship |publisher=Panorama |location=Mannheim |date=2010 |isbn=978-3-89823-435-1 |page=114}}</ref> with the possibility of a fifth:<ref name="de Manuel 2016"/><ref name="GVwEC">{{cite journal |last=Groves |first=C. P. |title=Geographic variation within eastern chimpanzees (''Pan troglodytes'' cf. ''schweinfurthii'' Giglioli, 1872) |volume=17 |pages=19–46 |journal=Australasian Primatology |year=2005}}</ref>
* [[Central chimpanzee]] or the [[tschego]] (''Pan troglodytes troglodytes''), found in [[Cameroon]], the [[Central African Republic]], [[Equatorial Guinea]], [[Gabon]], the [[Republic of the Congo]], and the [[Democratic Republic of the Congo]], with about 140,000 individuals existing in the wild.<ref name="IUCN_P.t. troglodytes">{{cite iucn |last1=Maisels |first1=F. |last2=Strindberg |first2=S. |last3=Greer |first3=D. |last4=Jeffery |first4=K. J. |last5=Morgan |first5=D. |last6=Sanz |first6=C. |year=2016 |title=''Pan troglodytes'' ssp. ''troglodytes'' |errata=2016 |volume=2016 |page=e.T15936A102332276 |doi=10.2305/IUCN.UK.2016-2.RLTS.T15936A17990042.en |access-date=27 August 2021}}</ref>
* [[Western chimpanzee]] (''P. troglodytes verus''), found in [[Ivory Coast]], [[Guinea]], [[Liberia]], [[Mali]], [[Sierra Leone]], [[Guinea-Bissau]], [[Senegal]], and [[Ghana]] with about 52,800 individuals still in existence.<ref>{{Cite journal |last1=Heinicke |first1=S. |last2=Mundry |first2=R. |last3=Boesch |first3=C. |last4=Amarasekaran |first4=B. |last5=Barrie |first5=A. |last6=Brncic |first6=T. |last7=Brugière |first7=D. |last8=Campbell |first8=G. |last9=Carvalho |first9=J. |last10=Danquah |first10=E. |last11=Dowd |first11=D. |year=2019 |title=Advancing conservation planning for western chimpanzees using IUCN SSC A.P.E.S.—the case of a taxon-specific database |journal=Environmental Research Letters |volume=14 |issue=6 |pages=064001 |doi=10.1088/1748-9326/ab1379 |bibcode=2019ERL....14f4001H |s2cid=159049588 |issn=1748-9326|doi-access=free |hdl=1893/29775 |hdl-access=free }}</ref><ref name="IUCN_P.t. verus">{{cite iucn |last1=Humle |first1=T. |last2=Boesch |first2=C. |last3=Campbell |first3=G. |last4=Junker |first4=J. |last5=Koops |first5=K. |last6=Kuehl |first6=H. |last7=Sop |first7=T. |year=2016 |title=''Pan troglodytes'' ssp. ''verus'' |errata=2016 |volume=2016 |page=e.T15935A102327574 |doi=10.2305/IUCN.UK.2016-2.RLTS.T15935A17989872.en |access-date=27 August 2021}}</ref>
* [[Nigeria-Cameroon chimpanzee]] (''P. troglodytes ellioti'' (also known as ''P. t. vellerosus'')),<ref name="Groves, Colin 2001 pp. 303-307"/> that live within forested areas across [[Nigeria]] and Cameroon, with 6000–9000 individuals still in existence.<ref>{{cite web |last1=Morgan |first1=Bethan J. |last2=Adeleke |first2=Alade |last3=Bassey |first3=Tony |last4=Bergl |first4=Richard |date=22 February 2011 |title=Regional action plan for the conservation of the Nigeria-Cameroon chimpanzee (Pan troglodytes ellioti) |url=https://portals.iucn.org/library/sites/library/files/documents/2011-123-En.pdf |archive-url=https://web.archive.org/web/20210224152328/https://portals.iucn.org/library/sites/library/files/documents/2011-123-En.pdf |access-date=9 February 2021 |archive-date=24 February 2021 |website=IUCN |language=en |url-status=live }}</ref><ref name="IUCN_P.t. ellioti">{{cite iucn |last=Oates |first1=J. F. |last2=Doumbe |first2=O. |last3=Dunn |first3=A. |last4=Gonder |first4=M. K. |last5=Ikemeh |first5=R. |last6=Imong |first6=I. |last7=Morgan |first7=B. J. |last8=Ogunjemite |first8=B. |last9=Sommer |first9=V. |year=2016 |title=''Pan troglodytes'' ssp. ''ellioti'' |volume=2016 |page=e.T40014A17990330 |doi=10.2305/IUCN.UK.2016-2.RLTS.T40014A17990330.en |access-date=27 August 2021}}</ref>
* [[Eastern chimpanzee]] (''P. troglodytes schweinfurthii''), found in the Central African Republic, [[South Sudan]], the Democratic Republic of the Congo, [[Uganda]], [[Rwanda]], [[Burundi]], [[Tanzania]], and [[Zambia]], with approximately 180,000–256,000 individuals still existing in the wild.<ref name="IUCN_P.t. schweinfurthii">{{cite iucn |last1=Plumptre |first1=A. |last2=Hart |first2=J. A. |last3=Hicks |first3=T. C. |last4=Nixon |first4=S. |last5=Piel |first5=A. K. |last6=Pintea |first6=L. |year=2016 |title=''Pan troglodytes'' ssp. ''schweinfurthii'' |volume=2016 |page=e.T15937A17990187 |access-date=27 August 2021}}</ref>
* Southeastern chimpanzee, ''P. troglodytes marungensis'', in Burundi, Rwanda, Tanzania, and Uganda. Colin Groves argues that this is a subspecies, created by enough variation between the northern and southern populations of ''P. t. schweinfurthii'',<ref name="GVwEC"/> but it is not recognised by the IUCN.<ref name="iucn"/>

===Genome===
{{Main |Chimpanzee genome project}}
{{align|left|{{Infobox genome|taxId=202|ploidy=diploid|chromosomes=24 pairs|size=3,323.27 Mb|year=}}}}
A draft version of the chimpanzee genome was published in 2005 and encodes 18,759 proteins,<ref name="genome">{{cite journal |author=Chimpanzee Sequencing and Analysis Consortium |title=Initial sequence of the chimpanzee genome and comparison with the human genome |journal=Nature |volume=437 |issue=7055 |pages=69–87 |date=September 2005 |pmid=16136131 |doi=10.1038/nature04072 |bibcode=2005Natur.437...69. |doi-access=free}}</ref><ref>{{Cite web |title=UniProt |url=https://www.uniprot.org/proteomes/UP000002277 |access-date=2022-08-07 |website=www.uniprot.org |archive-date=7 August 2022 |archive-url=https://web.archive.org/web/20220807233335/https://www.uniprot.org/proteomes/UP000002277 |url-status=live }}</ref> (compared to 20,383 in the human proteome).<ref>{{Cite web |title=UniProt |url=https://www.uniprot.org/uniprotkb?facets=reviewed:true&query=proteome:UP000005640 |access-date=2022-08-07 |website=www.uniprot.org |archive-date=7 August 2022 |archive-url=https://web.archive.org/web/20220807233335/https://www.uniprot.org/uniprotkb?facets=reviewed:true&query=proteome:UP000005640 |url-status=live }}</ref> The DNA sequences of humans and chimpanzees are very similar and the difference in protein number mostly arises from incomplete sequences in the chimpanzee genome. Both species differ by about 35 million [[Point mutation|single-nucleotide]] changes, five million [[Mutation#By effect on structure|insertion/deletion]] events and various [[Chromosomal translocation|chromosomal rearrangements]].<ref name="sequence">{{cite journal |last=Cheng |first=Z. |display-authors=etal |title=A genome-wide comparison of recent chimpanzee and human segmental duplications |journal=Nature |volume=437 |issue=7055 |pages=88–93 |date=September 2005 |pmid=16136132 |doi=10.1038/nature04000 |bibcode=2005Natur.437...88C|s2cid=4420359}}</ref> Typical human and chimpanzee protein [[homology (biology)|homologs]] differ in an average of only two [[amino acid]]s. About 30% of all human proteins are identical in sequence to the corresponding chimpanzee protein. Duplications of small parts of [[chromosome]]s have been the major source of differences between human and chimpanzee genetic material; about 2.7% of the corresponding modern genomes represent differences, produced by gene duplications or deletions{{Failed verification | date = October 2024 | reason = One reference clearly says the differences come from large segmental duplication (2.7%)—nothing about deletion—and single-base-pair substitution (1.2%). This statement doesn't reflect the abstract of the reference.}}, since humans and chimpanzees diverged from their common evolutionary ancestor.<ref name="genome"/><ref name="sequence"/>

==Characteristics==
[[File:Naturales IMG 1851.jpg|thumb|Skeleton]]
Adult chimpanzees have an average standing height of {{cvt|150|cm|ftin}}.<ref>{{Cite journal |year=2010 |last=Braccini |first=E. |title=Bipedal tool use strengthens chimpanzee hand preferences|journal=Journal of Human Evolution |volume=58 |issue=3 |pages=234–241 |doi=10.1016/j.jhevol.2009.11.008 |pmc=4675323 |pmid=20089294|bibcode=2010JHumE..58..234B }}</ref> Wild adult males weigh between {{cvt|40|and|70|kg}},<ref>{{Cite journal |year=1994 |last=Levi |first=M. |title=Inhibition of endotoxin-induced activation of coagulation and fibrinolysis by pentoxifylline or by a monoclonal anti-tissue factor antibody in chimpanzees. |journal=The Journal of Clinical Investigation |volume=93 |issue=1 |pages=114–120 |doi=10.1172/JCI116934 |pmid=8282778 |pmc=293743 |doi-access=free}}</ref><ref>{{Cite journal |year=1993 |last=Lewis |first=J. C. M. |title=Medetomidine-ketamine anaesthesia in the chimpanzee (''Pan troglodytes'') |journal=Journal of Veterinary Anaesthesia |volume=20 |pages=18–20 |doi=10.1111/j.1467-2995.1993.tb00103.x}}</ref><ref>{{Cite journal |year=1997 |last1=Smith |first1=R. J. |last2=Jungers |first2=W. L. |title=Body mass in comparative primatology |journal=Journal of Human Evolution |volume=32 |issue=6 |pages=523–559 |doi=10.1006/jhev.1996.0122 |pmid=9210017|bibcode=1997JHumE..32..523S }}</ref> and females weigh between {{cvt|27|and|50|kg}}.<ref name=":0">{{Cite book |url=https://books.google.com/books?id=q_4yCppoH8MC&q=chimps+weigh&pg=PA17 |title=Jane Goodall: Primatologist and Animal Activist |last=Jankowski |first=C. |publisher=Compass Point Books |year=2009 |isbn=978-0-7565-4054-8 |location=Mankato, MN, US |pages=14 |oclc=244481732}}</ref> In exceptional cases, certain individuals may considerably exceed these measurements, standing over {{cvt|168|cm|ftin|0}} on two legs and weighing up to {{cvt|136|kg}} in captivity.{{efn|One captive male, "Kermit", attained a height of {{cvt|168|cm|ftin|0}} and a body weight of {{cvt|82|kg}} when he was 11 years old.<ref>{{cite news |url=https://osupublicationarchives.osu.edu/?a=d&d=LTN19910404-01.2.30&e=-------en-20--1--txt-txIN------- |title=Researchers treat chimps like children |access-date=2 October 2020 |first=R. L. |last=Gedert |publisher=[[The Lantern]] |page=9 |date=4 April 1991 |archive-date=21 April 2022 |archive-url=https://web.archive.org/web/20220421233333/https://osupublicationarchives.osu.edu/?a=d&d=LTN19910404-01.2.30&e=-------en-20--1--txt-txIN------- |url-status=live }}</ref> As a fully grown adult, he weighed almost {{cvt|136|kg}}.<ref>{{cite news |last1=Taylor |first1=H. |last2=Cropper |first2=J. |url=https://www.thelantern.com/2006/03/recounting-dead-osu-chimps-last-day/ |title=Recounting dead OSU chimp's last day |publisher=[[The Lantern]] |date=6 March 2006 |access-date=21 December 2020 |archive-date=11 June 2021 |archive-url=https://web.archive.org/web/20210611150840/https://www.thelantern.com/2006/03/recounting-dead-osu-chimps-last-day/ |url-status=live }}</ref>}}

The chimpanzee is more robustly built than the bonobo but less than the [[gorilla]]. The arms of a chimpanzee are longer than its legs and can reach below the knees. The hands have long fingers with short thumbs and flat fingernails. The feet are adapted for grasping, and the big toe is [[Thumb#Opposition and apposition|opposable]]. The pelvis is long with an extended [[Ilium (bone)|ilium]]. A chimpanzee's head is rounded with a prominent and [[prognathous]] face and a pronounced [[brow ridge]]. It has forward-facing eyes, a small nose, rounded non-lobed ears and a long mobile upper lip. Additionally, adult males have sharp canine teeth. Like all great apes, it has a [[dental formula]] of {{DentalFormula|upper=2.1.2.3|lower=2.1.2.3}}, that is, two [[incisors]], one [[Canine tooth|canine]], two [[premolars]], and three [[Molar (tooth)|molars]] on both halves of each jaw.  Chimpanzees lack the prominent [[sagittal crest]] and associated head and neck musculature of gorillas.<ref name="Jones_etal.1996"/><ref name="Estes">{{cite book |last=Estes |first=R. |title=The Behavior Guide to African Mammals |url=https://archive.org/details/isbn_0520080858 |url-access=registration |pages=[https://archive.org/details/isbn_0520080858/page/545 545–557] |year=1991 |publisher=University of California Press |isbn=978-0-520-08085-0}}</ref>
[[File:Chimp and human hands.jpg|thumb|right|Chimpanzee hand (left) compared to human hand]]
Chimpanzee bodies are covered by coarse hair, except for the face, fingers, toes, palms of the hands, and soles of the feet. Chimpanzees lose more hair as they age and develop bald spots. The hair of a chimpanzee is typically black but can be brown or ginger. As they get older, white or grey patches may appear, particularly on the chin and lower region.<ref name="Jones_etal.1996"/><ref name="Estes"/> Chimpanzee skin that is covered with body hair is white, while exposed areas vary: white which ages into a dark muddy colour in eastern chimpanzees, freckled on white which ages to a heavily mottled muddy colour in central chimpanzees, and black with a butterfly-shaped white mask that darkens with age in western chimpanzees.<ref name="Post Szabó Keeling 1975">{{cite journal |last1=Post |first1=Peter W. |last2=Szabó |first2=George |last3=Keeling |first3=M. E. |year=1975 |title=A quantitative and morphological study of the pigmentary system of the chimpanzee with the light and electron microscope |journal=American Journal of Physical Anthropology |volume=43 |issue=3 |pages=435–443 |doi=10.1002/ajpa.1330430325 |pmid=1211438 |issn=0002-9483}}</ref><ref name="Napier Napier 1967">{{cite book |last1=Napier |first1=John Russell |title=A Handbook of Living Primates: Morphology, Ecology and Behaviour of Nonhuman Primates |last2=Napier |first2=Prue H. |date=1967 |publisher=Acad. Press |isbn=978-0-12-513850-5 |publication-place=London}}</ref> Facial pigmentation increases with age and exposure to ultraviolet light. Females develop swelling pink skin when in oestrus.<ref name="Jones_etal.1996"/><ref name="Estes"/>

Chimpanzees are adapted for both [[Arboreal locomotion|arboreal]] and [[terrestrial locomotion]]. Arboreal locomotion consists of vertical climbing and [[brachiation]].<ref>{{cite journal |last=Hun |first=K. D. |year=1991 |title=Mechanical implications of chimpanzee positional behavior |journal=American Journal of Physical Anthropology |volume=86 |issue=4 |pages=521–536 |doi=10.1002/ajpa.1330860408 |pmid=1776659}}</ref><ref>{{cite journal |last1=Pontzer |first1=H. |last2=Wrangham |first2=R. W. |author2-link=Richard Wrangham |year=2004 |title=Climbing and the daily energy cost of locomotion in wild chimpanzees: implications for hominoid locomotor evolution |journal=Journal of Human Evolution |volume=46 |issue=3 |pages=315–333 |doi=10.1016/j.jhevol.2003.12.006 |pmid=14984786|bibcode=2004JHumE..46..315P }}</ref> On the ground, chimpanzees move both quadrupedally and bipedally. These movements appear to have similar energy costs.<ref>{{cite journal |last1=Pontzer |first1=H. |last2=Raichlen |first2=D. A. |last3=Rodman |first3=P. S. |year=2014 |title=Bipedal and quadrupedal locomotion in chimpanzees |journal=Journal of Human Evolution |volume=66 |pages=64–82 |doi=10.1016/j.jhevol.2013.10.002 |pmid=24315239|bibcode=2014JHumE..66...64P }}</ref> As with bonobos and gorillas, chimpanzees move quadrupedally by [[knuckle-walking]], which probably evolved independently in ''Pan'' and ''Gorilla''.<ref>{{cite journal |last1=Kivell |first1=T. L. |last2=Schimtt |first2=D. |year=2009 |title=Independent evolution of knuckle-walking in African apes shows that humans did not evolve from a knuckle-walking ancestor |journal=Proceedings of the National Academy of Sciences |volume=106 |issue=34 |pages=14241–14246 |doi=10.1073/pnas.0901280106 |pmid=19667206 |pmc=2732797 |bibcode=2009PNAS..10614241K |doi-access=free}}</ref> Their muscles are 50% stronger per weight than those of humans due to higher content of [[Skeletal muscle#Twitch speed|fast twitch muscle fibres]], one of the chimpanzee's adaptations for climbing and swinging.<ref>{{cite journal |last1=O'Neill |first1=M. C. |last2=Umberger |first2=B. R. |last3=Holowka |first3=N. B. |last4=Larson |first4=S. G. |last5=Reiser |first5=P. J. |year=2017 |title=Chimpanzee super strength and human skeletal muscle evolution |journal=Proceedings of the National Academy of Sciences |volume=114 |issue=28 |pages=7343–7348 |doi=10.1073/pnas.1619071114 |pmid=28652350 |pmc=5514706 |bibcode=2017PNAS..114.7343O |doi-access=free}}</ref> According to Japan's [[Asahiyama Zoo]], the grip strength of an adult chimpanzee is estimated to be {{cvt|200|kg}},<ref>{{cite web |url=https://www.city.asahikawa.hokkaido.jp/asahiyamazoo/zuroku/africa/d056965.html |title=チンパンジー |date=18 June 2016 |trans-title=Chimpanzee |publisher=[[Asahiyama Zoo]] |language=Japanese |access-date=15 March 2021 |archive-date=18 May 2021 |archive-url=https://web.archive.org/web/20210518143402/https://www.city.asahikawa.hokkaido.jp/asahiyamazoo/zuroku/africa/d056965.html |url-status=live }}</ref> while other sources claim figures of up to {{cvt|330|kg}}.{{efn|According to A. S. Vanesyan's "Anthropology" (2015), a study by "Vorden" (probably 'Worden' or 'Warden') reported that a {{cvt|54|kg}} male chimpanzee squeezed {{cvt|330|kg}} on a dynamometer, while an angry female squeezed {{cvt|504|kg}} with both hands. Of the hundreds of human students who also participated in the experiment, only one could squeeze more than {{cvt|200|kg}} with both hands.<ref>{{cite book |last1=Ванесян |first1=A. |title=Антропология |date=2015 |publisher=Directmedia |isbn= 9785447539337 |page=113}}</ref> The source is said to be "Jan Dembowskiy, ''The Psychology of Monkeys''."<ref>{{Cite web |url=https://antropogenez.ru/quote/614/ |title=Где ты, шимпанзиный гений? Об интеллектуальных и физических возможностях шимпанзе |trans-title=Where are you, chimpanzee genius? About the intellectual and physical capabilities of chimpanzees |website=[[antropogenez.ru]] |language=Russian |access-date=27 August 2021 |archive-date=23 October 2021 |archive-url=https://web.archive.org/web/20211023004556/https://antropogenez.ru/quote/614/ |url-status=live }}</ref> This study is listed in: {{cite book | title=The Chimpanzee: A Topical Bibliography |edition=2nd |last=Dembowski |first=J. |chapter=Psychology of Monkeys |location=Warsaw |publisher=Ksrazka |date=1946 |url=https://apps.dtic.mil/dtic/tr/fulltext/u2/748249.pdf |pages=359 |access-date=19 March 2021 |url-status=dead |archive-url=https://web.archive.org/web/20210720184946/https://apps.dtic.mil/dtic/tr/fulltext/u2/748249.pdf |archive-date=20 July 2021}}}}

==Ecology==
[[File:Gombe_Stream_NP_Schlafstelle.jpg|thumb|right|Overnight nest in a tree]]
The chimpanzee is a highly adaptable species. It lives in a variety of habitats, including dry [[savanna]], [[evergreen]] rainforest, [[montane forest]], [[swamp forest]], and dry [[woodland]]-savanna mosaic.<ref name="Poulsen2004">{{cite journal |last1=Poulsen |first1=J. R. |last2=Clark |first2=C. J. |year=2004 |title=Densities, distributions, and seasonal movements of gorillas and chimpanzees in swamp forest in northern Congo |journal=International Journal of Primatology |volume=25 |issue=2 |pages=285–306 |doi=10.1023/B:IJOP.0000019153.50161.58 |s2cid=27022771}}</ref>{{sfn|Goodall|1986|p=44}} In [[Gombe Stream National Park|Gombe]], the chimpanzee mostly uses [[semideciduous]] and evergreen forest as well as open woodland.{{sfn|Goodall|1986|p=49}} At [[Bossou]], the chimpanzee inhabits multistage secondary [[deciduous forest]], which has grown after [[shifting cultivation]], as well as [[Old-growth forest|primary forest]] and grassland.<ref>{{cite journal |last1=Sugiyama |first1=Y. |last2=Koman |first2=J. |year=1987 |title=A preliminary list of chimpanzees' alimentation at Bossou, Guinea |journal=Primates |volume=28 |issue=1 |pages=133–47 |doi=10.1007/BF02382192|s2cid=6641715}}</ref> At [[Taï National Park|Taï]], it is found in the last remaining tropical rain forest in Ivory Coast.<ref>{{cite journal |title=The Taï chimpanzee project in Cote d'Ivoire, West Africa |journal=Pan Africa News |date=1994 |volume=1 |issue=1994 |page=2 |url=https://www.eva.mpg.de/fileadmin/content_files/staff/boesch/pdf/pan_af_new_tai_chimp_proj.pdf |archive-url=https://web.archive.org/web/20170106044441/http://www.eva.mpg.de/fileadmin/content_files/staff/boesch/pdf/pan_af_new_tai_chimp_proj.pdf |archive-date=2017-01-06 |url-status=live}}</ref> The chimpanzee has an advanced [[cognitive map]] of its home range and can repeatedly find food.{{sfn|Goodall|1986|p=237}} The chimpanzee builds a sleeping nest in a tree in a different location each night, never using the same nest more than once. Chimpanzees sleep alone in separate nests except for infants or juvenile chimpanzees, which sleep with their mothers.<ref name="behavior monographs"/>

===Diet===
[[File:Adult female and infant wild chimpanzees feeding on Ficus sur.jpeg|thumb|A mother with young eating ''[[Ficus sur|Ficus]]'' fruit in [[Kibale National Park]], Uganda]]
The chimpanzee is an [[omnivorous]] [[frugivore]]. It prefers fruit above all other food, but it also eats leaves, leaf buds, seeds, blossoms, stems, [[pith]], bark, and [[resin]].{{sfn|Goodall|1986|p=232}}<ref name="eat">{{cite web |last=Guernsey |first=P. |title=What do chimps eat? |url=http://www.allaboutwildlife.com/what-do-chimps-eat |work=All About Wildlife |access-date=22 April 2013 |date=4 July 2009 |archive-date=18 November 2019 |archive-url=https://web.archive.org/web/20191118084847/http://www.allaboutwildlife.com/what-do-chimps-eat |url-status=dead}}</ref> A study in [[Budongo Forest]], Uganda found that 64.5% of their feeding time concentrated on fruits (84.6% of which being ripe), particularly those from two species of ''[[Ficus]]'', ''[[Maesopsis eminii]]'', and ''[[Celtis gomphophylla]]''. In addition, 19% of feeding time was spent on arboreal leaves, mostly ''[[Broussonetia papyrifera]]'' and ''[[Celtis mildbraedii]]''.<ref>{{cite journal |last=Newton-Fisher |first=N. E. |year=1999 |title=The diet of chimpanzees in the Budongo Forest Reserve, Uganda |journal=African Journal of Ecology |volume=37 |issue=3 |pages=344–354 |doi=10.1046/j.1365-2028.1999.00186.x|bibcode=1999AfJEc..37..344N }}</ref> While the chimpanzee is mostly [[herbivorous]], it does eat honey, soil, insects, birds and their eggs, and small to medium-sized mammals, including other primates.{{sfn|Goodall|1986|p=232}}<ref>{{cite book |last=Isabirye-Basuta |first=G. |date=1989 |chapter=Feeding ecology of chimpanzees in the Kibale Forest, Uganda |pages=116–127 |editor-last1=Heltne |editor-first1=P. G. |editor-last2=Marquardt |editor-first2=L. A. |title=Understanding Chimpanzees |location=Cambridge, Massachusetts |publisher=Harvard University Press |isbn=978-0-674-92091-0 |chapter-url=https://archive.org/details/understandingchi0000unse |url=https://archive.org/details/understandingchi0000unse/page/116}}</ref> Insect species consumed include the [[weaver ant]] ''[[Oecophylla longinoda]]'', ''[[Macrotermes]]'' [[termite]]s, and [[honey bee]]s.<ref name="Tutin"/><ref name="Deblauwe"/> The [[red colobus]] ranks at the top of preferred mammal prey. Other mammalian prey include [[red-tailed monkey]]s, infant and juvenile [[yellow baboon]]s, [[bush babies]], [[blue duiker]]s, [[bushbuck]]s, and [[common warthog]]s.<ref>{{cite book |last1=Boesch |first1=C. |last2=Uehara |first2=S. |last3=Ihobe |first3=H. |date=2002 |chapter=Variations in chimpanzee-red colobus interactions |pages=221–30 |editor-last1=Boesch |editor-first1=C. |editor-last2=Hohmann |editor-first2=G. |editor-last3=Marchant |editor-first3=L. F. |title=Behavioral Diversity in Chimpanzees and Bonobos |location=Cambridge, UK |publisher=Cambridge University Press |isbn=978-0-521-00613-2}}</ref>

Despite the fact that chimpanzees are known to hunt and to collect both insects and other invertebrates, such food actually makes up a very small portion of their diet, from as little as 2% yearly to as much as 65 grams of animal flesh per day for each adult chimpanzee in peak hunting seasons. This also varies from troop to troop and year to year. However, in all cases, the majority of their diet consists of fruits, leaves, roots, and other plant matter.<ref name="eat"/><ref>{{cite web |last=Stanford |first=C. |title=The predatory behavior and ecology of wild chimpanzees |url=http://www-bcf.usc.edu/~stanford/chimphunt.html |publisher=USC |access-date=11 September 2013 |archive-url=https://web.archive.org/web/20130606110247/http://www-bcf.usc.edu/%7Estanford/chimphunt.html |archive-date=6 June 2013 |url-status=dead}}</ref> Female chimpanzees appear to consume much less animal flesh than males, according to several studies.<ref>{{cite journal |title=Chimpanzee hunting behavior |journal=American Scientist |volume=83 |issue=3 |pages=256 |first=N. E. |last=Newton-Fisher |url=https://kar.kent.ac.uk/27815/1/Newton-Fisher_2007_hunting_review.PDF |archive-url=https://web.archive.org/web/20160817131231/https://kar.kent.ac.uk/27815/1/Newton-Fisher_2007_hunting_review.PDF |archive-date=2016-08-17 |url-status=live |bibcode=1995AmSci..83..256S |year=1995}}</ref> [[Jane Goodall]] documented many occasions within [[Gombe Stream National Park]] of chimpanzees and western red colobus monkeys ignoring each other despite close proximity.<ref name="behavior monographs"/><ref>{{cite web |url=http://www.bbc.co.uk/nature/species/Common_Chimpanzee#p004hd8g |title=Chimps on the hunt |publisher=BBC Wildlife Finder |date=24 October 1990 |access-date=22 September 2009 |url-status=dead |archive-date=6 November 2010 |archive-url=https://web.archive.org/web/20101106073658/http://www.bbc.co.uk/nature/species/Common_Chimpanzee#p004hd8g}}</ref>

Chimpanzees do not appear to directly compete with gorillas in areas where they overlap. When fruit is abundant, gorilla and chimpanzee diets converge, but when fruit is scarce gorillas resort to vegetation.<ref name="Tutin1993">{{cite journal |last1=Tutin |first1=C. E. G. |last2=Fernandez |first2=M. |year=1993 |title=Composition of the diet of chimpanzees and comparisons with that of sympatric lowland gorillas in the Lopé reserve, Gabon |journal=American Journal of Primatology |volume=30 |issue=3 |pages=195–211 |doi=10.1002/ajp.1350300305 |pmid=31937009 |s2cid=84681736}}</ref> The two apes may also feed on different species, whether fruit or insects.<ref name="Tutin">{{cite journal |last1=Tutin|first1=C. E. G. |last2=Fernandez|first2=M. |year=1992 |title=Insect-eating by sympatric lowland gorillas (''Gorilla g. gorilla'') and chimpanzees (''Pan t. troglodytes'') in the Lopé Reserve, Gabon |journal=American Journal of Primatology |volume=28 |issue=1 |pages=29–40 |doi=10.1002/ajp.1350280103 |pmid=31941221 |s2cid=85569302}}</ref><ref name="Deblauwe">{{cite journal |last=Deblauwe |first=I. |year=2007 |title=New insights in insect prey choice by chimpanzees and gorillas in Southeast Cameroon: the role of nutritional value |journal=American Journal of Physical Anthropology |volume=135 |issue=1 |pages=42–55 |doi=10.1002/ajpa.20703 |pmid=17902166}}</ref><ref>{{cite journal |last1=Stanford |first1=C. B. |last2=Nkurunungi |first2=J. B. |year=2003 |title=Behavioral ecology of sympatric chimpanzees and gorillas in Bwindi Impenetrable National Park, Uganda: Diet |journal=International Journal of Primatology |volume=24 |issue=4 |pages=901–918 |doi=10.1023/A:1024689008159|s2cid=22587913}}</ref> Interactions between them can range from friendly and even stable social bonding,<ref>{{cite journal|last1=Sanz|first1=C. M.|display-authors=etal|year=2022|title=Interspecific interactions between sympatric apes|journal=iScience|volume=25|issue=10|page=105059|doi=10.1016/j.isci.2022.105059|pmid=36147956 |pmc=9485909 |bibcode=2022iSci...25j5059S }}</ref> to avoidance,<ref name="Tutin1993"/><ref>{{cite book |last=Galdikas|first=B. M. |author-link=Birutė Galdikas |year=2005 |title=Great Ape Odyssey |publisher=Abrams |page=89 |isbn=978-1-4351-1009-0}}</ref> to aggression and even predation of infants on the part of chimpanzees.<ref>{{Cite journal |last1=Southern |first1=L. M. |last2=Deschner |first2=T. |last3=Pika |first3=S. |year=2021 |title=Lethal coalitionary attacks of chimpanzees (''Pan troglodytes troglodytes'') on gorillas (''Gorilla gorilla gorilla'') in the wild |journal=Scientific Reports |volume=11 |issue=1 |page=14673 |doi=10.1038/s41598-021-93829-x |pmid=34282175 |pmc=8290027|bibcode=2021NatSR..1114673S}}</ref>

===Mortality and health===
[[File:2006-12-09 Chimpanzee Gregoire D Bruyere.JPG|thumb|Chimpanzee named "Gregoire" on 9 December 2006, born in 1944 (Jane Goodall sanctuary of Tchimpounga, [[Republic of the Congo]])]]
The average lifespan of a wild chimpanzee is relatively short. They usually live less than 15 years, although individuals that reach 12 years may live an additional 15 years. On rare occasions, wild chimpanzees may live nearly 60 years. Captive chimpanzees tend to live longer than most wild ones, with median lifespans of 31.7 years for males and 38.7 years for females.<ref>{{cite web |last=Mulchay |first=J. B. |date=8 March 2013 |title=How long do chimpanzees live? |url=https://chimpsnw.org/2013/03/how-long-do-chimpanzees-live/ |access-date=28 March 2019 |publisher=Chimpanzee Sanctuary Northwest |archive-date=28 March 2019 |archive-url=https://web.archive.org/web/20190328194722/https://chimpsnw.org/2013/03/how-long-do-chimpanzees-live/ |url-status=live }}</ref> The oldest-known male captive chimpanzee to have been documented lived to 66 years,<ref>{{Cite web |date=24 December 2008 |title=Africa's oldest chimp, a conservation icon, dies |website=Discovery News |url=http://dsc.discovery.com/news/2008/12/23/gregoire-oldest-chimp.html |archive-url=https://web.archive.org/web/20081224073912/http://dsc.discovery.com/news/2008/12/23/gregoire-oldest-chimp.html |archive-date=24 December 2008 |url-status=dead |access-date=24 October 2020}}</ref> and the oldest female, [[Little Mama]], was nearly 80 years old.<ref>{{Cite news |last=Goodall |first=J. |date=27 November 2017 |title=Sad loss of Little Mama, one of the oldest chimps |work=janegoodall.org |url=https://news.janegoodall.org/2017/11/27/sad-loss-little-mama-one-oldest-chimps/ |access-date=22 July 2021 |archive-date=22 July 2021 |archive-url=https://web.archive.org/web/20210722144347/https://news.janegoodall.org/2017/11/27/sad-loss-little-mama-one-oldest-chimps/ |url-status=live }}</ref>

[[Leopard]]s prey on chimpanzees in some areas.<ref name="Boesch 1991">{{cite journal |last=Boesch |first=C. |s2cid=84213757 |title=The effects of leopard predation on grouping patterns in forest chimpanzees |journal=Behaviour |volume=117 |issue=3–4 |year=1991 |doi=10.1163/156853991x00544 |pages=220–241 |jstor=4534940}}</ref><ref>{{cite journal |last1=Henschel |first1=P. |last2=Abernethy |first2=K. A. |last3=White |first3=L. J. |year=2005 |title=Leopard food habits in the Lopé National Park, Gabon, Central Africa |journal=African Journal of Ecology |volume=43 |issue=1 |pages=21–8 |doi=10.1111/j.1365-2028.2004.00518.x|bibcode=2005AfJEc..43...21H }}</ref> It is possible that much of the mortality caused by leopards can be attributed to individuals that have specialised in killing chimpanzees.<ref name="Boesch 1991"/> Chimpanzees may react to a leopard's presence with loud vocalising, branch shaking, and throwing objects.<ref name="Boesch 1991"/><ref>{{cite journal |last=Pierce |first=A. H |year=2009 |title=An encounter between a leopard and a group of chimpanzees at Gombe National Park |journal=Pan Africa News |volume=16 |issue=22–24 |doi=10.5134/143505 |doi-access=free}}</ref> There is at least one record of chimpanzees killing a leopard cub after [[Mobbing (animal behavior)|mobbing]] it and its mother in their den.<ref>{{cite journal |last=Hiraiwa-Hasegawa |first=M. |display-authors=etal |year=1986 |title=Aggression toward large carnivores by wild chimpanzees of Mahale Mountains National Park, Tanzania |journal=Folia Primatologica; International Journal of Primatology |volume=47 |issue=1 |pages=8–13 |pmid=3557232 |doi=10.1159/000156259}}</ref> Four chimpanzees could have fallen prey to [[lion]]s at [[Mahale Mountains National Park]]. Although no other instances of lion predation on chimpanzees have been recorded, lions likely do kill chimpanzees occasionally, and the larger group sizes of savanna chimpanzees may have developed as a response to threats from these big cats. Chimpanzees may react to lions by fleeing up trees, vocalising, or hiding in silence.<ref name="Tsukahara">{{cite journal |last=Tsukahara |first=T. |year=1992 |title=Lions eat chimpanzees: the first evidence of predation by lions on wild chimpanzees |journal=American Journal of Primatology |volume=29 |issue=1 |pages=1–11 |doi=10.1002/ajp.1350290102 |pmid=31941199 |s2cid=84565926}}</ref>
[[File:Pediculus schaeffi.JPG|thumb|upright|The chimpanzee louse ''Pediculus schaeffi'' is closely related to the human body louse ''[[Pediculus humanus|P. humanus]]''.]]
Chimpanzees and humans share only 50% of their [[parasite]] and [[microbe]] species. This is due to the differences in environmental and dietary adaptations; human internal parasite species overlap more with omnivorous, savanna-dwelling baboons. The chimpanzee is host to the [[louse]] species ''Pediculus schaeffi'', a close relative of ''[[Pediculus humanus|P. humanus]]'', which infests human head and body hair. By contrast, the human pubic louse ''[[Pthirus pubis]]'' is closely related to ''[[Pthirus gorillae]]'', which infests gorillas.<ref name="Weiss, Robin A. 2009 20">{{cite journal |last=Weiss |first=R. A. |year=2009 |title=Apes, lice and prehistory |journal=Journal of Biology |volume=8 |issue=2 |page=20 |doi=10.1186/jbiol114 |pmc=2687769 |pmid=19232074 |doi-access=free }}</ref> A 2017 study of gastro[[intestinal parasite]]s of wild chimpanzees in degraded forest in Uganda found nine species of [[protozoa]], five [[nematode]]s, one [[cestode]], and one [[trematode]]. The most prevalent species was the protozoan ''Troglodytella abrassarti''.<ref>{{cite journal |last1=McLennan |first1=M. R. |last2=Hasegawa |first2=Hideo |last3=Bardi |first3=Massimo |last4=Huffman |first4=Michael A. |year=2017 |title=Gastrointestinal parasite infections and self-medication in wild chimpanzees surviving in degraded forest fragments within an agricultural landscape mosaic in Uganda |journal=PLOS ONE |volume=12 |issue=7 |at=e0180431 |doi=10.1371/journal.pone.0180431 |pmid=28692673 |pmc=5503243 |bibcode=2017PLoSO..1280431M |doi-access=free}}</ref>

==Behaviour==
Recent studies have suggested that human observers influence chimpanzee behaviour. One suggestion is that [[Unmanned aerial vehicle|drone]]s, camera traps, and remote microphones should be used to record and monitor chimpanzees rather than direct human observation.<ref>{{cite journal |last1=Hobaiter |first1=C. |last2=Samuni |first2=L. |last3=Mullins |first3=C. |last4=Akankwasa |first4=W. J. |last5=Zuberbühler |first5=K. |year=2017 |title=Variation in hunting behaviour in neighbouring chimpanzee communities in the Budongo forest, Uganda |journal=PLOS ONE |volume=12 |issue=6 |page=e0178065 |doi=10.1371/journal.pone.0178065 |pmid=28636646 |pmc=5479531 |bibcode=2017PLoSO..1278065H |doi-access=free}}</ref>{{Failed verification | date = October 2024 | reason = The research mentions nothing about drone, cameras, or microphones.}}

===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>

===Mating and parenting===
[[File:Gombe Stream NP Mutter und Kind.jpg|thumb|upright|Infant and mother]]
Chimpanzees mate throughout the year, although the number of females in [[oestrus]] varies seasonally in a group.<ref name="Wallis2002">{{cite book |author=Wallis, J. |date=2002 |chapter=Seasonal aspects of reproduction and sexual behavior in two chimpanzee populations: a comparison of Gombe (Tanzania) and Budongo (Uganda) |pages=181–191 |editor=Boesch, C. |editor2=Hohmann, G. |editor3=Marchant, L. F. |title=Behavioural diversity in chimpanzees and bonobos |location=Cambridge, UK |publisher=Cambridge University Press |isbn=978-0-521-00613-2}}</ref> Female chimpanzees are more likely to come into oestrus when food is readily available. Oestrous females exhibit [[sexual swelling]]s. Chimpanzees are [[promiscuous]]: during oestrus, females mate with several males in their community, while males have large testicles for [[sperm competition]]. Other forms of mating also exist. A community's dominant males sometimes restrict reproductive access to females. A male and female can form a consortship and mate outside their community. In addition, females sometimes leave their community and mate with males from neighboring communities.{{sfn|Goodall|1986|pp=450–451}}<ref name="Gagneux1999">{{cite journal |author=Gagneux, P. |author2=Boesch, C. |author3=Woodruff, D. S. |s2cid=25981874 |title=Female reproductive strategies, paternity and community structure in wild West African chimpanzees |journal=Animal Behaviour |volume=57 |issue=1 |pages=19–32 |date=1999 |pmid=10053068 |doi=10.1006/anbe.1998.0972}}</ref> These [[alternative mating strategy|alternative mating strategies]] give females more mating opportunities without losing the support of the males in their community.<ref name="Gagneux1999"/> [[Infanticide in primates|Infanticide]] has been recorded in chimpanzee communities in some areas, and the victims are often consumed. Male chimpanzees practice infanticide on unrelated young to shorten the interbirth intervals in the females.<ref>{{cite journal |author1=Watts, D. P. |author2=Mitani, J. C. |year=2000 |title=Infanticide and cannibalism by male chimpanzees at Ngogo, Kibale National Park, Uganda |journal=Primates |volume=41 |issue=4 |pages=357–365 |doi=10.1007/BF02557646 |pmid=30545199 |s2cid=22595511}}</ref><ref name="Goodall1977">{{cite journal |author=Goodall, J. |author-link=Jane Goodall |title=Infant killing and cannibalism in free-living chimpanzees |journal=Folia Primatologica; International Journal of Primatology |volume=28 |issue=4 |pages=259–89 |year=1977 |pmid=564321 |doi=10.1159/000155817}}</ref> Females sometimes practice infanticide. This may be related to the dominance hierarchy in females or may simply be pathological.<ref name="Pusey1997">{{cite journal |author1=Pusey, A. |author2=Williams, J. |author3=Goodall, J. |author3-link=Jane Goodall |title=The influence of dominance rank on the reproductive success of female chimpanzees |journal=Science |volume=277 |issue=5327 |pages=828–831 |date=August 1997 |pmid=9242614 |doi=10.1126/science.277.5327.828}}</ref>

[[Inbreeding]] was studied in a relatively undisturbed eastern bisexual chimpanzee community.<ref name = White2024>{{cite journal |last1=White |first1=LC |last2=Städele |first2=V |last3=Ramirez Amaya |first3=S |last4=Langergraber |first4=K |last5=Vigilant |first5=L |title=Female chimpanzees avoid inbreeding even in the presence of substantial bisexual philopatry |journal=R Soc Open Sci |date=17 Jan 2024 |volume=11 |issue=1 |page=230967 |doi=10.1098/rsos.230967 |pmid=38234436 |pmc=10791533|bibcode=2024RSOS...1130967W }}</ref> Despite an increased inbreeding risk incurred by females who do not disperse before reaching reproductive age, these females were still able to [[Inbreeding avoidance|avoid]] producing inbred offspring.<ref name = White2024/>

[[Copulation (zoology)|Copulation]] is brief, lasting approximately seven seconds.<ref name="Dixson2012">{{cite book |first=A. F. |last=Dixson |title=Primate Sexuality: Comparative Studies of the Prosimians, Monkeys, Apes, and Humans |date=2012 |publisher=OUP Oxford |isbn=978-0-19-150342-9}}</ref> The [[gestation]] period is eight months.<ref name="Estes"/> Care for the young is provided mostly by their mothers. The survival and emotional health of the young is dependent on maternal care. Mothers provide their young with food, warmth, and protection, and teach them certain skills. In addition, a chimpanzee's future rank may be dependent on its mother's status.{{sfn|Goodall|1986|pp=203–205}}<ref name="Foerster Franz Murray Gilby">{{cite journal |last1=Foerster |first1=S. |last2=Franz |first2=M. |last3=Murray |first3=C. M. |last4=Gilby |first4=I. C. |last5=Feldblum |first5=J. T. |last6=Walker |first6=K. K. |last7=Pusey |first7=A. E. |title=Chimpanzee females queue but males compete for social status |journal=Scientific Reports |volume=6 |issue=1 |date=2016 |doi=10.1038/srep35404 |pmid=27739527 |pmc=5064376 |page=35404 |bibcode=2016NatSR...635404F}}</ref> Male chimpanzees continue to associate with the females they impregnated and interact with and support their offspring.<ref>{{cite journal|last1=Murray|first1=C. M.|last2=Stanton|first2=M. A.|last3=Lonsdorf|first3=E. V.|last4=Wroblewski|first4=E. E.|last5=Pusey|first5=A. E.|year=2016|title=Chimpanzee fathers bias their behaviour towards their offspring|journal=Royal Society Open Science|volume=3|issue=11|page=160441 |doi=10.1098/rsos.160441|pmid=28018626 |pmc=5180124 |bibcode=2016RSOS....360441M }}</ref> Newborn chimpanzees are helpless. For example, their grasping reflex is not strong enough to support them for more than a few seconds. For their first 30 days, infants cling to their mother's bellies. Infants are unable to support their own weight for their first two months and need their mothers' support.<ref name="Bard1995">{{cite book |last=Bard |first=K. A. |editor-last=Bornstein |editor-first=M. H. |title=Handbook of Parenting |volume=2 |chapter=Parenting in nonhuman primates |publisher=Routledge, Taylor & Francis Group |location=New York |year=2019 |orig-date=1995 |isbn=978-0-429-68588-0 |oclc=1089683467}}</ref>

When they reach five to six months, infants ride on their mothers' backs. They remain in continual contact for the rest of their first year. When they reach two years of age, they are able to move and sit independently and start moving beyond the arms' reach of their mothers. By four to six years, chimpanzees are weaned and infancy ends. The juvenile period for chimpanzees lasts from their sixth to ninth years. Juveniles remain close to their mothers, but interact an increasing amount with other members of their community. Adolescent females move between groups and are supported by their mothers in agonistic encounters. Adolescent males spend time with adult males in social activities like hunting and boundary patrolling.<ref name="Bard1995"/> A captive study suggests males can safely immigrate to a new group if accompanied by immigrant females who have an existing relationship with this male. This gives the resident males reproductive advantages with these females, as they are more inclined to remain in the group if their male friend is also accepted.<ref>{{Cite journal |last1=Goetschi |first1=F. |last2=McClung |first2=J. |last3=Baumeyer |first3=A. |last4=Zuberbuhler |first4=K. |date=2020-02-01 |title=Chimpanzee immigration: complex social strategies differ between zoo-based and wild animals |journal=Journal of Zoo and Aquarium Research |volume=8 |issue=1 |doi=10.19227/jzar.v8i1.326 |hdl=10023/19397 |issn=2214-7594}}</ref>

===Communication===
{{listen|filename=Pant-hoot call made by a male chimpanzee.ogg|title=Pant-hoot call|description=Pant-hoot call made by an adult male, demonstrating the introduction, build-up, climax, and let-down phases.<ref name="Fedurek">{{Cite journal |last1=Fedurek |first1=P. |last2=Zuberbühler |first2=K. |last3=Semple |first3=S. |date=2017 |title=Trade-offs in the production of animal vocal sequences: insights from the structure of wild chimpanzee pant hoots |journal=Frontiers in Zoology |volume=14 |pages=50 |doi=10.1186/s12983-017-0235-8 |pmc=5674848 |pmid=29142585 |doi-access=free }}</ref>|format=[[Vorbis]]}}
Chimpanzees use facial expressions, postures, and sounds to communicate with each other. Chimpanzees have expressive faces that are important in close-up communications. When frightened, a "full closed grin" causes nearby individuals to be fearful, as well. Playful chimpanzees display an open-mouthed grin. Chimpanzees may also express themselves with the "pout", which is made in distress, the "sneer", which is made when threatening or fearful, and "compressed-lips face", which is a type of display. When submitting to a dominant individual, a chimpanzee crunches, bobs, and extends a hand. When in an aggressive mode, a chimpanzee swaggers bipedally, hunched over and arms waving, in an attempt to exaggerate its size.{{sfn|Goodall|1986|pp=119–122}} While travelling, chimpanzees keep in contact by beating their hands and feet against the trunks of large trees, an act that is known as "drumming". They also do this when encountering individuals from other communities.<ref name="Crockford2005">{{cite journal |last1=Crockford |first1=C. |last2=Boesch |first2=C. |s2cid=84677208 |year=2005 |title=Call combinations in wild chimpanzees |journal=Behaviour |volume=142 |issue=4 |pages=397–421 |doi=10.1163/1568539054012047}}</ref>

Vocalisations are also important in chimpanzee communication. The most common call in adults is the "[[Pant-hoot (call)|pant-hoot]]", which may signal social rank and bond along with keeping groups together. Pant-hoots are made of four parts, starting with soft "hoos", the introduction; that gets louder and louder, the build-up; and climax into screams and sometimes barks; these die down back to soft "hoos" during the letdown phase as the call ends.<ref name="Fedurek"/><ref name="Crockford2005"/> Grunting is made in situations like feeding and greeting.<ref name="Crockford2005"/> Submissive individuals make "pant-grunts" towards their superiors.<ref name="Pusey1997"/>{{sfn|Goodall|1986|p=129}} Whimpering is made by young chimpanzees as a form of begging or when lost from the group.<ref name="Crockford2005"/> Chimpanzees use distance calls to draw attention to danger, food sources, or other community members.{{sfn|Goodall|1986|pp=132–133}} "Barks" may be made as "short barks" when hunting and "tonal barks" when sighting large snakes.<ref name="Crockford2005"/>
[[File:Gombe Stream NP Beute.jpg|thumb|Adult male eastern chimpanzee snatches a dead [[bushbuck antelope]] from a baboon in [[Gombe Stream National Park]].]]

===Hunting===
When hunting small monkeys such as the [[Western red colobus|red colobus]], chimpanzees hunt where the forest canopy is interrupted or irregular. This allows them to easily corner the monkeys when chasing them in the appropriate direction. Chimpanzees may also hunt as a coordinated team, so that they can corner their prey even in a continuous canopy. During an [[arboreal]] hunt, each chimpanzee in the hunting groups has a role. "Drivers" serve to keep the prey running in a certain direction and follow them without attempting to make a catch. "Blockers" are stationed at the bottom of the trees and climb up to block prey that takes off in a different direction. "Chasers" move quickly and try to make a catch. Finally, "ambushers" hide and rush out when a monkey nears.<ref name="Leipzig2002">{{cite journal |author=Boesch, C. |title=Cooperative hunting roles among Taï chimpanzees |journal=Human Nature |volume=13 |issue=1 |pages=27–46 |year=2002 |pmid=26192594 |doi=10.1007/s12110-002-1013-6 |citeseerx=10.1.1.556.2265|s2cid=15905236}}</ref> While both adults and infants are taken, adult male colobus monkeys will attack the hunting chimps.{{sfn|Goodall|1986|pp=273–274}} When caught and killed, the meal is distributed to all hunting party members and even bystanders.<ref name="Leipzig2002"/>

Male chimpanzees hunt in groups more than females. Female chimpanzees tend to hunt solitarily. If a female chimpanzee were to participate in the hunting group and catch a Red Colobus, it would likely immediately be taken by an adult male. Female chimpanzees are estimated to hunt ≈ 10-15% of a community's vertebrates.<ref>{{Cite journal |last1=Gilby |first1=Ian C. |last2=Machanda |first2=Zarin P. |last3=O’Malley |first3=Robert C. |last4=Murray |first4=Carson M. |last5=Lonsdorf |first5=Elizabeth V. |last6=Walker |first6=Kara |last7=Mjungu |first7=Deus C. |last8=Otali |first8=Emily |last9=Muller |first9=Martin N. |last10=Thompson |first10=Melissa Emery |last11=Pusey |first11=Anne E. |last12=Wrangham |first12=Richard W. |date=September 2017 |title=Predation by female chimpanzees: toward an understanding of sex differences in meat acquisition in the last common ancestor of Pan and Homo |journal=Journal of Human Evolution |volume=110 |pages=82–94 |doi=10.1016/j.jhevol.2017.06.015 |issn=0047-2484 |pmc=5570454 |pmid=28778463|bibcode=2017JHumE.110...82G }}</ref>

==Intelligence==
{{further|Primate cognition}}
[[File:Man&chimpbrains.png|thumb|left|alt=Drawing of human and chimpanzee skull and brain|Human and chimpanzee skull and brain. Diagram by [[Paul Gervais]] from ''Histoire naturelle des mammifères'' (1854).]]
Chimpanzees display numerous signs of intelligence, from the ability to remember symbols<ref name="symbol"/> to cooperation,<ref name="recruit"/> tool use,<ref name="Boesch1993"/> and varied [[Great ape language|language capabilities]].<ref name="GAT"/> They are among species that have passed the [[mirror test]], suggesting [[self-awareness]].<ref>{{cite journal |first=D. |last=Povinelli |author2=de Veer, M. |author3=Gallup Jr., G. |author4=Theall, L. |author5=van den Bos, R. |title=An 8-year longitudinal study of mirror self-recognition in chimpanzees (''Pan troglodytes'') |journal=Neuropsychologia |volume=41 |issue=2 |pages=229–334 |doi=10.1016/S0028-3932(02)00153-7 |pmid=12459221 |year=2003|s2cid=9400080}}</ref> In one study, two young chimpanzees showed retention of mirror self-recognition after one year without access to mirrors.<ref>{{cite journal |last1=Calhoun |first1=S. |last2=Thompson |first2=R. L. |name-list-style=amp |year=1988 |title=Long-term retention of self-recognition by chimpanzees |journal=American Journal of Primatology |volume=15 |issue=4 |pages=361–365 |doi=10.1002/ajp.1350150409 |pmid=31968884 |s2cid=84381806}}</ref> Chimpanzees have been observed to use insects to treat their own wounds and those of others. They catch them and apply them directly to the injury.<ref>{{cite journal|last1=Mascaro|first1=A.|last2=Southern|first2=L. M.|last3=Deschner|first3=T.|last4=Pika|first4=S.|year=2022|title=Application of insects to wounds of self and others by chimpanzees in the wild|journal=Current Biology|volume=32|issue=3|pages=R112–R113|doi=10.1016/j.cub.2021.12.045|pmid=35134354|s2cid=246638843|doi-access=free|bibcode=2022CBio...32.R112M }}</ref> Chimpanzees also display signs of [[animal culture|culture]] among groups, with the learning and transmission of variations in grooming, tool use and foraging techniques leading to localized traditions.<ref>{{cite journal |first1=A.|last1=Whiten |first2=A. |last2=Spiteri |first3=V. |last3=Horner |first4=K. E. |last4=Bonnie |first5=S. P. |last5=Lambeth |first6=S. J. |last6=Schapiro |first7=F. B. M. |last7=de Waal |author7-link=Frans de Waal |title=Transmission of multiple traditions within and between chimpanzee groups |journal=Current Biology |volume=17 |issue=12 |date=2007 |pages=1038–1043 |doi=10.1016/j.cub.2007.05.031 |pmid=17555968 |s2cid=1236151|doi-access=free |bibcode=2007CBio...17.1038W }}</ref>

A 30-year study at [[Kyoto University]]'s [[Primate Research Institute]] has shown that chimpanzees are able to learn to recognise the numbers 1 to 9 and their values. The chimpanzees further show an aptitude for [[eidetic memory]], demonstrated in experiments in which the jumbled digits are flashed onto a computer screen for less than a quarter of a second. One chimpanzee, [[Ayumu (chimpanzee)|Ayumu]], was able to correctly and quickly point to the positions where they appeared in ascending order. Ayumu performed better than human adults who were given the same test.<ref name="symbol">{{cite journal |author=Matsuzawa, T. |year=2009 |title=Symbolic representation of number in chimpanzees |journal=Current Opinion in Neurobiology |volume=19 |issue=1 |pages=92–98 |doi=10.1016/j.conb.2009.04.007 |pmid=19447029 |s2cid=14799654}}</ref>

In controlled [[cooperative pulling paradigm|experiments on cooperation]], chimpanzees show a basic understanding of cooperation, and recruit the best collaborators.<ref name="recruit">{{cite journal |last1=Melis |first1=A. P. |first2=B. |last2=Hare |first3=M. |last3=Tomasello |s2cid=9219039 |title=Chimpanzees recruit the best collaborators |journal=Science |volume=311 |issue=5765 |year=2006 |pages=1297–1300 |bibcode=2006Sci...311.1297M |doi=10.1126/science.1123007 |pmid=16513985}}</ref> In a group setting with a device that delivered food rewards only to cooperating chimpanzees, cooperation first increased, then, due to competitive behaviour, decreased, before finally increasing to the highest level through punishment and other arbitrage behaviours.<ref name="Suchak">{{cite journal |last1=Suchak |first1=M. |first2=T. M. |last2=Eppley |first3=M. W. |last3=Campbell |first4=R. A. |last4=Feldman |first5=L. F. |last5=Quarles |first6=F. B. M. |last6=de Waal |author6-link=Frans de Waal |title=How chimpanzees cooperate in a competitive world |journal=Proceedings of the National Academy of Sciences |year=2016 |volume=113 |issue=36 |pages=10215–10220 |doi=10.1073/pnas.1611826113 |pmid=27551075 |pmc=5018789 |bibcode=2016PNAS..11310215S |doi-access=free}}</ref>

Great apes show [[Laughter in animals|laughter-like vocalisations]] in response to physical contact, such as wrestling, play chasing, or [[tickling]]. This is documented in wild and captive chimpanzees. Chimpanzee laughter is not readily recognisable to humans as such, because it is generated by alternating inhalations and exhalations that sound more like breathing and panting. Instances in which nonhuman primates have expressed joy have been reported. Humans and chimpanzees share similar ticklish areas of the body, such as the armpits and belly. The enjoyment of tickling in chimpanzees does not diminish with age.<ref name="Discover2003">{{Cite web |author=Johnson, S. |date=1 April 2003 |title=Emotions and the brain |url=http://discovermagazine.com/2003/apr/featlaugh |url-status=dead |publisher=Discover Magazine |access-date=11 March 2019 |archive-date=19 July 2011 |archive-url=https://web.archive.org/web/20110719034137/http://discovermagazine.com/2003/apr/featlaugh }}</ref>

Chimpanzees have displayed different behaviours in response to a dying or dead group member. When witnessing a sudden death, the other group members act in frenzy, with vocalisations, aggressive displays, and touching of the corpse. In one case chimpanzees cared for a dying elder, then attended and cleaned the corpse. Afterward, they avoided the spot where the elder died and behaved in a more subdued manner.<ref>{{cite journal |author1=Anderson, J. R. |author2=Gillies, A. |author3=Lock, L. C. |year=2010 |title=''Pan'' thanatology |journal=Current Biology |volume=20 |issue=8 |pages=R349–R351 |doi=10.1016/j.cub.2010.02.010 |pmid=21749950|s2cid=21208590|doi-access=free |bibcode=2010CBio...20.R349A }}</ref> Mothers have been reported to carry around and groom their dead infants for several days.<ref>{{cite journal |author1=Dora, B. |author2=Humle, T. |author3=Koops, K. |author4=Sousa, C. |author5=Hayashi, M. |author6=Matsuzawa, T. |year=2010 |title=Chimpanzee mothers at Bossou, Guinea carry the mummified remains of their dead infants |journal=Current Biology |volume=20 |issue=8 |pages=R351–R352 |doi=10.1016/j.cub.2010.02.031 |pmid=21749951|s2cid=52333419|doi-access=free |bibcode=2010CBio...20.R351B }}</ref>

Experimenters now and then witness behaviour that cannot be readily reconciled with chimpanzee intelligence or [[theory of mind]]. [[Wolfgang Köhler]], for instance, reported insightful behaviour in chimpanzees, but he likewise often observed that they experienced "special difficulty" in solving simple problems.<ref>{{Cite book |last=Köhler |first=Wolfgang |author-link=Wolfgang Köhler |year=1925 |title=The mentality of apes |edition=1st |others=translated from the 2nd German edition by Ella Winter |location=London |publisher=Kegan Paul Trench Trubner & Co. |page=65 |url=https://archive.org/details/in.ernet.dli.2015.187610/page/n69/mode/2up?q=special+difficulty}} See also Wiki page [[The Mentality of Apes]].</ref> Researchers also reported that, when faced with a choice between two persons, chimpanzees were just as likely to beg food from a person who could see the begging gesture as from a person who could not, thereby raising the possibility that chimpanzees lack [[theory of mind]].<ref>{{Cite journal |last1=Povinelli |first1=D. J. |last2=Eddy |first2=T. J. |year=1996 |title=What young chimpanzees know about seeing |journal=Monographs of the Society for Research in Child Development |volume=61 |issue=3 |pages=1–189|doi=10.2307/1166159 |jstor=1166159}}</ref>

===Tool use===
{{further |Tool use by animals}}
[[File:Cultural-differences-in-ant-dipping-tool-length-between-neighbouring-chimpanzee-communities-at-srep12456-s2.ogv|thumb|right |Chimpanzees using twigs to dip for ants]]
Nearly all chimpanzee populations have been recorded using tools. They modify sticks, rocks, grass, and leaves and use them when foraging for termites and ants,<ref name=":1">{{Cite journal |last1=Humle |first1=T. |last2=Matsuzawa |first2=T. |date=2001 |title=Behavioural diversity among the wild chimpanzee populations of Bossou and neighbouring areas, Guinea and Côte d'Ivoire, West Africa |journal=Folia Primatologica |volume=72 |issue=2 |pages=57–68 |doi=10.1159/000049924 |pmid=11490130 |s2cid=19827175 |issn=0015-5713}}</ref> nuts,<ref name=":1"/><ref>{{Cite journal |last=Ohashi |first=G. |date=2015 |title=Pestle-pounding and nut-cracking by wild chimpanzees at Kpala, Liberia |journal=Primates |volume=56 |issue=2 |pages=113–117 |doi=10.1007/s10329-015-0459-1 |pmid=25721009 |s2cid=18857210 |issn=0032-8332}}</ref><ref>{{Cite journal |last1=Hannah |first1=A. C. |last2=McGrew |first2=W. C. |date=1987 |title=Chimpanzees using stones to crack open oil palm nuts in Liberia |journal=Primates |volume=28 |issue=1 |pages=31–46 |doi=10.1007/BF02382181 |s2cid=24738945 |issn=1610-7365}}</ref><ref>{{Cite journal |last1=Marshall-Pescini |first1=S. |last2=Whiten |first2=A. |date=2008 |title=Chimpanzees (''Pan troglodytes'') and the question of cumulative culture: an experimental approach |journal=Animal Cognition |volume=11 |issue=3 |pages=449–456 |doi=10.1007/s10071-007-0135-y |pmid=18204869 |s2cid=25295372 |issn=1435-9448}}</ref> honey,<ref>{{Cite journal |last1=Boesch |first1=C. |last2=Head |first2=J. |last3=Robbins |first3=M. M. |date=June 2009 |title=Complex tool sets for honey extraction among chimpanzees in Loango National Park, Gabon |journal=Journal of Human Evolution |volume=56 |issue=6 |pages=560–569 |doi=10.1016/j.jhevol.2009.04.001 |pmid=19457542 |bibcode=2009JHumE..56..560B |issn=0047-2484}}</ref> algae<ref>{{Cite journal |last1=Boesch |first1=C. |last2=Kalan |first2=A. K. |last3=Agbor |first3=A. |last4=Arandjelovic |first4=M. |last5=Dieguez |first5=P. |last6=Lapeyre |first6=V. |last7=Kühl |first7=H. S. |date=2016 |title=Chimpanzees routinely fish for algae with tools during the dry season in Bakoun, Guinea |journal=American Journal of Primatology |volume=79 |issue=3 |pages=e22613 |doi=10.1002/ajp.22613 |pmid=27813136 |s2cid=24832972 |issn=0275-2565}}</ref> or water. Despite the lack of complexity, forethought and skill are apparent in making these tools.<ref name="Boesch1993">{{cite book |author=Boesch, C. |author2=Boesch, H. |date=1993 |chapter=Diversity of tool use and tool-making in wild chimpanzees |pages=158–87 |editor=Berthelet, A. |editor2=Chavaillon, J. |title=The Use of Tools by Human and Non-human Primates |location=Oxford, UK |publisher=Oxford University Press |isbn=978-0-19-852263-8}}</ref> Chimpanzees have used stone tools since at least 4,300 years ago.<ref>{{cite journal |author=Mercader. J. |display-authors=etal |title=4,300-year-old chimpanzee sites and the origins of percussive stone technology |journal=PNAS |volume=104 |issue=9 |pages=3043–8 |date=February 2007 |pmid=17360606 |pmc=1805589 |doi=10.1073/pnas.0607909104 |bibcode=2007PNAS..104.3043M |doi-access=free}}</ref>

A chimpanzee from the [[Kasakela chimpanzee community]] was the first nonhuman animal reported making a tool, by modifying a twig to use as an instrument for extracting termites from their mound.<ref name="Goodall 1971">{{cite book |title=In the Shadow of Man |author=Goodall, J. |author-link=Jane Goodall |pages=[https://archive.org/details/inshadowofman300good/page/35 35–37] |year=1971 |publisher=Houghton Mifflin |isbn=978-0-395-33145-3 |url=https://archive.org/details/inshadowofman300good/page/35}}</ref><ref>{{cite web |title=Gombe timeline |url=http://www.janegoodall.org/jane/study-corner/chimpanzees/gombe-timeline.asp |archive-url=https://web.archive.org/web/20080125194313/http://www.janegoodall.org/jane/study-corner/chimpanzees/gombe-timeline.asp |archive-date=25 January 2008 |publisher=[[Jane Goodall Institute]] |access-date=5 March 2009}}</ref> At Taï, chimpanzees simply use their hands to extract termites.<ref name="Boesch1993"/> When foraging for honey, chimpanzees use modified short sticks to scoop the honey out of the hive if the bees are [[Stingless bees|stingless]]. For hives of the dangerous [[African honeybee]]s, chimpanzees use longer and thinner sticks to extract the honey.<ref>{{cite journal |author=Stanford, C. B. |display-authors=etal |title=Chimpanzees in Bwindi-Impenetrable National Park, Uganda, use different tools to obtain different types of honey |journal=Primates; Journal of Primatology |volume=41 |issue=3 |pages=337–341 |date=July 2000 |pmid=30545184 |doi=10.1007/BF02557602 |s2cid=23000084}}</ref>

Chimpanzees also fish for ants using the same tactic.<ref name="Boesch Boesch 1982"/> Ant dipping is difficult and some chimpanzees never master it. West African chimpanzees crack open hard nuts with stones or branches.<ref name="Boesch1993"/><ref name="Boesch Boesch 1982">{{cite journal |last1=Boesch |first1=C. |last2=Boesch |first2=H. |s2cid=85037244 |title=Optimisation of nut-cracking with natural hammers by wild chimpanzees |journal=Behaviour |date=1982 |volume=83 |issue=3/4 |pages=265–286 |jstor=4534230 |doi=10.1163/156853983x00192}}</ref> Some forethought in this activity is apparent, as these tools are not found together or where the nuts are collected. Nut cracking is also difficult and must be learned.<ref name="Boesch Boesch 1982"/> Chimpanzees also use leaves as sponges or spoons to drink water.<ref>{{cite journal |author=Sugiyama, Y. |year=1995 |title=Drinking tools of wild chimpanzees at Bossou |journal=American Journal of Primatology |volume=37 |issue=1 |pages=263–269 |doi=10.1002/ajp.1350370308 |pmid=31936951 |s2cid=86473603}}</ref>

West African chimpanzees in Senegal were found to sharpen sticks with their teeth, which were then used to spear [[Senegal bushbaby|Senegal bushbabies]] out of small holes in trees.<ref>{{cite web |url=http://news.discovery.com/animals/female-chimps-seen-making-wielding-spears-150414.htm |title=Female chimps seen making, wielding spears |last1=Viegas |first1=J. |date=14 April 2015 |publisher=Discovery |access-date=15 April 2015 |archive-date=15 April 2015 |archive-url=https://web.archive.org/web/20150415123148/http://news.discovery.com/animals/female-chimps-seen-making-wielding-spears-150414.htm |url-status=dead}}</ref> An eastern chimpanzee has been observed using a modified branch as a tool to capture a [[squirrel]].<ref>{{cite journal |author=Huffman, M. A. |author2=Kalunde, M. S. |title=Tool-assisted predation on a squirrel by a female chimpanzee in the Mahale Mountains, Tanzania |journal=Primates |date=January 1993 |volume=34 |issue=1 |pages=93–98 |doi=10.1007/BF02381285 |s2cid=28006860}}</ref>

Whilst experimental studies on captive chimpanzees have found that many of their species-typical tool-use behaviours can be individually learnt by each chimpanzees,<ref>{{cite journal |last1=Bandini |first1=E. |last2=Tennie |first2=C. |title=Exploring the role of individual learning in animal tool-use |journal=PeerJ |date=2020 |volume=8 |issue=e9877 |pages=e9877 |doi=10.7717/peerj.9877 |pmid=33033659 |pmc=7521350 |doi-access=free }}</ref> a 2021 study on their abilities to make and use stone flakes, in a similar way as hypothesised for early hominins, did not find this behaviour across two populations of chimpanzees—suggesting that this behaviour is outside the chimpanzee species-typical range.<ref>{{cite journal |last1=Bandini |first1=E. |last2=Motes-Rodrigo |first2=A. |last3=Archer |first3=W. |last4=Minchin |first4=T. |last5=Axelsen |first5=H. |last6=Hernandez-Aguilar |first6=R. A. |last7=McPherron |first7=S. |last8=Tennie |first8=C. |title=Naïve, unenculturated chimpanzees fail to make and use flaked stone tools |journal=Open Research Europe |date=2021 |volume=1 |issue=20 |page=20 |doi=10.12688/openreseurope.13186.2|pmid=35253007 |pmc=7612464 |s2cid=237868827 |doi-access=free }}</ref>

===Language===
{{Main |Great ape language}}
[[File:HugoRheinholdApeWithSkull.DarwinMonkey.2.jpg|thumb|upright|right|[[Hugo Rheinhold]]'s ''[[Affe mit Schädel]]'' ("Ape with skull"), {{Circa|1893}}]]
Scientists have attempted to teach human [[language]] to several species of great ape. One early attempt by Allen and Beatrix Gardner in the 1960s involved spending 51 months teaching [[American Sign Language]] to a chimpanzee named [[Washoe (chimpanzee)|Washoe]]. The Gardners reported that Washoe learned 151 signs, and had spontaneously taught them to other chimpanzees, including her adopted son, [[Loulis]].<ref>{{Cite journal |author1=Gardner, R. A. |author2=Gardner, B. T. |year=1969 |title=Teaching sign language to a chimpanzee |journal=Science |volume=165 |pages=664–672 |doi=10.1126/science.165.3894.664 |pmid=5793972 |issue=3894 |bibcode=1969Sci...165..664G |citeseerx=10.1.1.384.4164}}</ref> Over a longer period of time, Washoe was reported to have learned over 350 signs.<ref>{{Cite book |author1=Allen, G. R. |author2=Gardner, B. T. |year=1980 |chapter=Comparative psychology and language acquisition |editor-first1=T. A. |editor-last1=Sebok |editor-first2=J. |editor-last2=Umiker-Sebok |title=Speaking of Apes: A Critical Anthology of Two-Way Communication with Man |location=New York |publisher=Plenum Press |pages=287–329 |isbn=978-0-306-40279-1}}</ref>

Debate is ongoing among scientists such as [[David Premack]] about chimpanzees' ability to learn language. Since the early reports on Washoe, numerous other studies have been conducted, with varying levels of success.<ref name="GAT">{{cite web |url=http://www.greatapetrust.org/bonobo/language/ |title=Language of bonobos |publisher=Great Ape Trust |archive-url=https://web.archive.org/web/20040815161414/http://www.greatapetrust.org/bonobo/language/ |archive-date=15 August 2004 |access-date=16 January 2012}}</ref> One involved a chimpanzee jokingly named [[Nim Chimpsky]] (in allusion to the theorist of language [[Noam Chomsky]]), trained by Herbert Terrace of [[Columbia University]]. Although his initial reports were quite positive, in November 1979, Terrace and his team, including psycholinguist [[Thomas Bever]], re-evaluated the videotapes of Nim with his trainers, analyzing them frame by frame for signs, as well as for exact context (what was happening both before and after Nim's signs). In the reanalysis, Terrace and Bever concluded that Nim's utterances could be explained merely as prompting on the part of the experimenters, as well as mistakes in reporting the data. "Much of the apes' behaviour is pure drill", he said. "Language still stands as an important definition of the human species." In this reversal, Terrace now argued Nim's use of ASL was not like human [[language acquisition]]. Nim never initiated conversations himself, rarely introduced new words, and mostly imitated what the humans did. More importantly, Nim's word strings varied in their ordering, suggesting that he was incapable of [[syntax]]. Nim's sentences also did not grow in length, unlike human children whose vocabulary and sentence length show a strong positive correlation.<ref name="Wynne 2007">{{cite web |author-link1=Clive Wynne |last=Wynne |first=C. |url=http://www.skeptic.com/eskeptic/07-10-31 |title=Aping language |work=eSkeptic |publisher=Skeptic |date=31 October 2007 |access-date=28 January 2011 |archive-date=16 April 2011 |archive-url=https://web.archive.org/web/20110416095851/http://www.skeptic.com/eskeptic/07-10-31/ |url-status=live }}</ref>

==Human relations==

===In culture===
[[File:Schimpansenmaske kaogle Liberia Museum Rietberg RAF 428.jpg|thumb|left|upright|Chimpanzee mask, [[Gio people|Gio tribe]], Liberia]]
Chimpanzees are rarely represented in [[African culture]], as people find them "too close for comfort". The [[Gio people]] of Liberia and the [[Hemba people]] of the Congo make chimpanzee masks. Gio masks are crude and blocky, and worn when teaching young people how not to behave. The Hemba masks have a smile that suggests drunken anger, insanity or horror and are worn during rituals at funerals, representing the "awful reality of death". The masks may also serve to guard households and protect both human and plant fertility. Stories have been told of chimpanzees kidnapping and raping women.<ref name="symbolism">{{cite book |first=H. B. |last=Werness |year=2007 |title=The Continuum Encyclopedia of Animal Symbolism in World Art |publisher=Continuum International Publishing Group |page=86 |isbn=978-0-8264-1913-2}}</ref>

In Western [[popular culture]], chimpanzees have occasionally been stereotyped as childlike companions, [[sidekick]]s or [[clowns]]. They are especially suited for the latter role on account of their prominent facial features, long limbs and fast movements, which humans often find amusing. Accordingly, entertainment acts featuring chimpanzees dressed up as humans with [[lip-sync]]hronised human voices have been traditional staples of [[circus]]es, [[stage show]]s and TV shows like ''[[Lancelot Link, Secret Chimp]]'' (1970–1972) and ''[[The Chimp Channel]]'' (1999).<ref name="Van Riper 19">{{Cite book |last=Van Riper |first=A. B. |title=Science in popular culture: a reference guide |url=https://archive.org/details/sciencepopularcu00ripe |url-access=limited |publisher=[[Greenwood Press]] |location=Westport |year=2002 |pages=[https://archive.org/details/sciencepopularcu00ripe/page/n35 18]–19 |isbn=978-0-313-31822-1}}</ref> From 1926 until 1972, [[London Zoo]], followed by several other zoos around the world, held a [[chimpanzees' tea party]] daily, inspiring a long-running series of advertisements for [[PG Tips#Advertising|PG Tips]] tea featuring such a party.<ref>{{cite book |last=Warner |first=M. |author-link=Marina Warner |title=Monsters of our own making: the peculiar pleasures of fear |publisher=University Press of Kentucky |year=2007 |page=335 |isbn=978-0-8131-9174-4}}</ref><ref name="Heath 2014">{{cite web |last1=Heath |first1=Neil |title=PG Tips chimps: The last of the tea-advertising apes |url=https://www.bbc.co.uk/news/uk-england-leicestershire-23508215 |publisher=[[BBC]] |access-date=30 March 2019 |date=9 January 2014 |archive-date=30 March 2019 |archive-url=https://web.archive.org/web/20190330183848/https://www.bbc.co.uk/news/uk-england-leicestershire-23508215 |url-status=live }}</ref> [[Animal rights]] groups have urged a stop to such acts, considering them abusive.<ref>{{cite web |url=http://www.nomoremonkeybusiness.com/ |title=Animal actors |publisher=Nomoremonkeybusiness.com |access-date=28 January 2011 |archive-url=https://web.archive.org/web/20100303121336/http://www.nomoremonkeybusiness.com/ |archive-date=3 March 2010 |url-status=dead}}</ref>
[[File:Aping Hollywood poster.jpg|thumb|upright|Poster for the 1931 film ''Aping Hollywood''. Media like this relied on the novelty of performing apes to carry their gags.<ref name="Van Riper 19"/>]]
Chimpanzees in media include Judy on the television series ''[[Daktari]]'' in the 1960s and Darwin on ''[[The Wild Thornberrys]]'' in the 1990s. In contrast to the fictional depictions of other animals, such as dogs (as in ''[[Lassie]]''), dolphins (''[[Flipper (1964 TV series)|Flipper]]''), horses (''[[The Black Stallion]]'') or even other great apes (''[[King Kong]]''), chimpanzee characters and actions are rarely relevant to the plot. Depictions of chimpanzees as individuals rather than stock characters, and as central rather than incidental to the plot can be found in [[science fiction]]. [[Robert A. Heinlein]]'s 1947 short story "[[Jerry Was a Man]]" concerns a [[biological uplift|genetically enhanced]] chimpanzee suing for better treatment. The 1972 film ''[[Conquest of the Planet of the Apes]]'', the third sequel of the 1968 film ''[[Planet of the Apes (1968 film)|Planet of the Apes]]'', portrays a futuristic revolt of enslaved apes led by the only talking chimpanzee, [[Caesar (Planet of the Apes)|Caesar]], against their human masters.<ref name="Van Riper 19"/>

===As pets===
Chimpanzees have traditionally been kept as pets in a few African villages, especially in the [[Democratic Republic of Congo]]. In [[Virunga National Park]] in the east of the country, the park authorities regularly confiscate chimpanzees from people keeping them as pets.<ref>{{Cite news |url=http://news.bbc.co.uk/1/hi/sci/tech/7839819.stm |work=BBC News |title=Gorilla diary: August – December 2008 |date=20 January 2009 |access-date=28 April 2010 |archive-date=5 February 2009 |archive-url=https://web.archive.org/web/20090205031918/http://news.bbc.co.uk/1/hi/sci/tech/7839819.stm |url-status=live }}</ref> Outside their range, chimpanzees are popular as [[exotic pet]]s despite their strength and aggression. Even in places where keeping non-human primates as pets is illegal, the exotic pet trade continues to prosper, leading to injuries from attacks.<ref>{{cite web |title=Chimpanzees don't make good pets |url=http://www.janegoodall.org/chimp-central-pets |website=The Jane Goodall Institute |access-date=1 February 2015 |url-status=dead |archive-url=https://web.archive.org/web/20150202195221/http://www.janegoodall.org/chimp-central-pets |archive-date=2 February 2015}}</ref>

===Use in research===
{{see also|Countries banning non-human ape experimentation|Animal testing on non-human primates#Chimpanzees in the U.S.}}
Hundreds of chimpanzees have been kept in laboratories for research. Most such laboratories either conduct or make the animals available for invasive research,<ref name="HSUSmap">{{cite web |url=http://www.hsus.org/animals_in_research/chimps_deserve_better/research/chimpanzee-lab-and-sanctuary-map.html |title=Chimpanzee lab and sanctuary map |publisher=[[Humane Society of the United States]] |access-date=24 March 2008 |url-status=dead |archive-url=https://web.archive.org/web/20080307055400/http://www.hsus.org/animals_in_research/chimps_deserve_better/research/chimpanzee-lab-and-sanctuary-map.html |archive-date=7 March 2008}}</ref> defined as "inoculation with an infectious agent, surgery or biopsy conducted for the sake of research and not for the sake of the chimpanzee, and/or drug testing".<ref name="HSUSresearch">{{cite web |url=http://www.hsus.org/animals_in_research/chimps_deserve_better/research/overview_of_research_uses_and.html |title=Chimpanzee research: overview of research uses and costs |publisher=[[Humane Society of the United States]] |access-date=24 March 2008 |archive-url=https://web.archive.org/web/20080307055406/http://www.hsus.org/animals_in_research/chimps_deserve_better/research/overview_of_research_uses_and.html |archive-date=7 March 2008}}</ref> Research chimpanzees tend to be used repeatedly over decades for up to 40 years, unlike the pattern of use of most laboratory animals.<ref name="HSUSbetter">{{cite web |archive-url=https://web.archive.org/web/20080215112131/http://www.hsus.org/animals_in_research/chimps_deserve_better/ |archive-date=15 February 2008 |url=http://www.hsus.org/animals_in_research/chimps_deserve_better/ |url-status=dead |title=Chimps deserve better |publisher=[[Humane Society of the United States]]}}</ref> Two federally funded American laboratories use chimpanzees: the [[Yerkes National Primate Research Center]] at [[Emory University]] in Atlanta, Georgia, and the Southwest National Primate Center in San Antonio, Texas.<ref name="Lovgren">{{cite web |last=Lovgren |first=S. |title=Should labs treat chimps more like humans? |website=[[National Geographic News]] |url=http://news.nationalgeographic.com/news/2005/09/0906_050906_chimplabs.html |url-status=dead |date=6 September 2005 |archive-url=https://archive.today/20050923121728/http://news.nationalgeographic.com/news/2005/09/0906_050906_chimplabs.html |archive-date=23 September 2005}}</ref> Five hundred chimpanzees have been retired from laboratory use in the US and live in [[Animal sanctuary|animal sanctuaries]] in the US or Canada.<ref name="HSUSmap"/>

A five-year moratorium was imposed by the US National Institutes of Health in 1996, because too many chimpanzees had been bred for HIV research, and it has been extended annually since 2001.<ref name="Lovgren"/> With the publication of the [[chimpanzee genome]], plans to increase the use of chimpanzees in America were reportedly increasing in 2006, some scientists arguing that the federal moratorium on breeding chimpanzees for research should be lifted.<ref name="Lovgren"/><ref name="Langley15">{{cite web |author-link=Gill Langley |last=Langley |first=G. |date=June 2006 |url=http://www.eceae.org/english/documents/NoKReport.pdf |title=Next of kin: a report on the use of primates in experiments |archive-url=https://web.archive.org/web/20071128121456/http://www.eceae.org/english/documents/NoKReport.pdf |archive-date=28 November 2007 |publisher=British Union for the Abolition of Vivisection |page=15}} citing {{cite journal |author=VandeBerg, J. L. |author2=Zola, S. M. |title=A unique biomedical resource at risk |journal=Nature |volume=437 |issue=7055 |pages=30–32 |date=September 2005 |pmid=16136112 |doi=10.1038/437030a |bibcode=2005Natur.437...30V|s2cid=4346309}}</ref> However, in 2007, the NIH made the moratorium permanent.<ref name="Dunham">{{cite web |last=Dunham |first=W. |website=[[Reuters]] |title=US stops breeding chimps for research |date=24 May 2007 |access-date=20 May 2021 |url=https://www.reuters.com/article/us-chimpanzees-research-usa-idUSN2438996920070524 |url-status=live |archive-date=21 May 2021 |archive-url=https://archive.today/20210521023010/https://www.reuters.com/article/us-chimpanzees-research-usa-idUSN2438996920070524}}</ref>
[[File:Chimpanzee Ham in Biopack Couch for MR-2 flight MSFC-6100114.jpg |left|thumb |[[Ham (chimpanzee)|Ham]], the first great ape in space, before being inserted into his [[Mercury-Redstone 2]] capsule on 31 January 1961]]
Other researchers argue that chimpanzees either should not be used in research, or should be treated differently, for instance with [[Great ape personhood|legal status as persons]].<ref>{{cite encyclopedia |author=Karcher, K. |title=The Great Ape Project |editor=Bekoff, M. |editor-link=Marc Bekoff |encyclopedia=The Encyclopedia of Animal Rights and Animal Welfare |publisher=Greenwood |year=2009 |pages=185–187}}</ref> Pascal Gagneux, an evolutionary biologist and primate expert at the [[University of California, San Diego]], argues, given chimpanzees' sense of self, tool use, and genetic similarity to human beings, studies using chimpanzees should follow the ethical guidelines used for human subjects unable to give consent.<ref name="Lovgren"/> A recent study suggests chimpanzees which are retired from labs exhibit a form of [[post-traumatic stress disorder]].<ref>{{cite journal |doi=10.1080/15299730802073619 |author1=Bradshaw, G. A. |author2=Capaldo, T. |author3=Lindner, L. |author4=Grow, G. |title=Building an inner sanctuary: complex PTSD in chimpanzees |journal=Journal of Trauma & Dissociation |volume=9 |issue=1 |pages=9–34 |year=2008 |pmid=19042307 |s2cid=12632717 |url=http://www.releasechimps.org/pdfs/ExecSumTraumaFINAL.pdf |archive-url=https://web.archive.org/web/20080512152142/http://www.releasechimps.org/pdfs/ExecSumTraumaFINAL.pdf |archive-date=2008-05-12 |url-status=live}}</ref> Stuart Zola, director of the Yerkes laboratory, disagrees. He told ''National Geographic'': "I don't think we should make a distinction between our obligation to treat humanely any species, whether it's a rat or a monkey or a chimpanzee. No matter how much we may wish it, chimps are not human."<ref name="Lovgren"/>

Only one European laboratory, the [[Biomedical Primate Research Centre]] in [[Rijswijk]], the Netherlands, used chimpanzees in research. It formerly held 108 chimpanzees among 1,300 non-human primates. The Dutch ministry of science decided to phase out research at the centre from 2001.<ref>{{cite journal |last1=Goodman |first1=S. |title=Europe brings experiments on chimpanzees to an end |journal=[[Nature (journal)|Nature]] |volume=411 |date=10 May 2001 |issue=6834 |page=123 |doi=10.1038/35075735 |pmid=11346754 |bibcode=2001Natur.411..123G |doi-access=free}}</ref> Trials already under way were however allowed to run their course.<ref>{{cite news |title=Lab chimps face housing crisis: experiments on apes end, but problems remain |url=https://www.nbcnews.com/id/wbna5761824 |agency=[[Associated Press]] |date=19 August 2004 |access-date=11 November 2019 |archive-date=24 September 2020 |archive-url=https://web.archive.org/web/20200924003557/http://www.nbcnews.com/id/5761824 |url-status=live }}</ref> Chimpanzees including the female [[Ai (chimpanzee)|Ai]] have been studied at the [[Primate Research Institute]] of [[Kyoto University]], Japan, formerly directed by [[Tetsuro Matsuzawa]], since 1978. 12 chimpanzees are currently{{When|date=June 2024}} held at the facility.<ref>{{cite web |title=Chimpanzee Ai |url=https://langint.pri.kyoto-u.ac.jp/ai/en/friends/ai.html |publisher=Kyoto University |access-date=27 August 2021 |archive-date=12 October 2021 |archive-url=https://web.archive.org/web/20211012031752/https://langint.pri.kyoto-u.ac.jp/ai/en/friends/ai.html |url-status=dead }}</ref>

Two chimpanzees have been [[Monkeys and apes in space|sent into outer space]] as [[NASA]] research subjects. [[Ham (chimpanzee)|Ham]], the first great ape in space, was launched in the [[Mercury-Redstone 2]] capsule on 31 January 1961, and survived the suborbital flight. [[Enos (chimpanzee)|Enos]], the third primate to orbit Earth after Soviet cosmonauts [[Yuri Gagarin]] and [[Gherman Titov]], flew on [[Mercury-Atlas 5]] on 29 November of the same year.<ref>{{cite web |author=Betz, E. |date=21 April 2020 |title=Animals in space: a brief history of 'astrochimps' |publisher=Astronomy.com |access-date=8 June 2021 |url=https://astronomy.com/news/2020/04/animals-in-space-a-brief-history-of-astro-chimps |archive-date=9 June 2021 |archive-url=https://web.archive.org/web/20210609021913/https://astronomy.com/news/2020/04/animals-in-space-a-brief-history-of-astro-chimps |url-status=live }}</ref><ref>{{Cite book |last1=Swenson |first1=L.S.Jr. |last2=Grimwood |first2=J.M. |last3=Alexander |first3=C.C. |year=1989 |editor1-last=Woods |editor1-first=D. |editor2-last=Gamble |editor2-first=C. |title=This New Ocean: A History of Project Mercury |series=NASA History Series (Special Publication-4201) |publisher=[[NASA]] |url=https://history.nasa.gov/SP-4201/toc.htm |access-date=1 December 2023 |archive-date=23 August 2007 |archive-url=https://web.archive.org/web/20070823124845/https://history.nasa.gov/SP-4201/toc.htm |url-status=live }}</ref>

===Field study===
[[File:Gombe Stream NP Fuetterungsstation.jpg|right|thumb|Feeding station at Gombe, where [[Jane Goodall]] used to feed and observe the chimpanzees]]
[[Jane Goodall]] undertook the first long-term field study of the chimpanzee, begun in Tanzania at [[Gombe Stream National Park]] in 1960.<ref name="nat.geo.04.03.">{{cite magazine |title=Jane in the forest again |url=http://ngm.nationalgeographic.com/ngm/0304/feature5/fulltext.html |archive-url=https://web.archive.org/web/20071210041539/http://ngm.nationalgeographic.com/ngm/0304/feature5/fulltext.html |url-status=dead |archive-date=10 December 2007 |magazine=National Geographic |date=April 2003 |access-date=17 November 2014}}</ref> Other long-term studies begun in the 1960s include [[Adriaan Kortlandt]]'s in the eastern [[Democratic Republic of the Congo]] and [[Toshisada Nishida]]'s in [[Mahale Mountains National Park]] in Tanzania.<ref>{{cite book |last=Nishida |first=T. |year=2012 |title=Chimpanzees of the Lakeshore: Natural History and Culture at Mahale |location=Cambridge, UK |publisher=Cambridge University Press}}</ref><ref>{{cite news |last=Cohen |first=J. E. |title=Going bananas |publisher=American Scholar |date=Winter 1993 |pages=154–157}}</ref> Current understanding of the species' typical behaviours and social organisation has been formed largely from Goodall's ongoing 60-year Gombe research study.<ref name="Power.Anthropologist">{{cite journal |last=Power |first=M. |title=Divergence population genetics of chimpanzees |journal=American Anthropologist |volume=95 |date=December 1993 |pages=1010–11 |issue=4 |doi=10.1525/aa.1993.95.4.02a00180}}</ref><ref name=long>{{cite book |title=Long-term Field Studies of Primates |url=https://archive.org/details/longtermfieldstu00kapp|url-access=limited |editor1=Kappeler, P. M. |editor2=Watts, D. P. |chapter=Long-term studies of the chimpanzees of Gombe National Park, Tanzania |author=Wilson, M. L. |chapter-url=https://archive.org/details/longtermfieldstu00kapp/page/n377 |pages=357–384 |publisher=Springer |year=2012 |isbn=9783642225130}}</ref><ref name="Wilson et al. (2020)">{{cite journal |last1=Wilson |first1=M. L. |display-authors=etal |title=Research and conservation in the greater Gombe ecosystem: challenges and opportunities |journal=Biological Conservation |date=2020 |volume=252 |page=108853 |doi=10.1016/j.biocon.2020.108853 |pmid=33343005 |pmc=7743041|bibcode=2020BCons.25208853W }}</ref>

===Attacks===
Chimpanzees have attacked humans.<ref>{{cite web |url=http://www.monkeyday.org/2006/04/texas-man-tells-story-of-fatal-chimp.html |title=Texas man saves friend during fatal chimp attack |access-date=27 June 2006 |last=Osborn |first=C. |date=27 April 2006 |work=The Pulse Journal |archive-url=https://web.archive.org/web/20190608085455/http://www.monkeyday.org/2006/04/texas-man-tells-story-of-fatal-chimp.html |archive-date=8 June 2019 |url-status=dead}}</ref><ref>{{cite news |title=Chimp attack kills cabbie and injures tourists |url=https://www.theguardian.com/international/story/0,,1760554,00.html |newspaper=[[The Guardian]] |access-date=27 June 2006 |date=25 April 2006 |location=London}}</ref> In Uganda, several attacks on children have happened, some of them fatal. Some of these attacks may have been due to the chimpanzees being intoxicated (from alcohol obtained from rural brewing operations) and becoming aggressive towards humans.<ref>{{cite web |url=http://www.primates.com/chimps/drunk-n-disorderly.html |title='Drunk and disorderly' chimps attacking Ugandan children |access-date=27 June 2006 |date=9 February 2004 |first1=Wairagala |last1=Wakabi |agency=EastAfrican |via=primates.com |archive-url=https://web.archive.org/web/20060619230813/http://www.primates.com/chimps/drunk-n-disorderly.html |archive-date=19 June 2006 |url-status=dead}}</ref> Human interactions with chimpanzees may be especially dangerous if the chimpanzees perceive humans as potential rivals.<ref>{{cite web |url=https://www.nbcnews.com/id/wbna7087194 |title=Chimp attack doesn't surprise experts |access-date=27 June 2006 |date=5 March 2005 |work=NBC News |archive-date=10 October 2013 |archive-url=https://web.archive.org/web/20131010224318/http://www.nbcnews.com/id/7087194/ |url-status=live }}</ref> At least six cases of chimpanzees snatching and eating human babies are documented.<ref>{{cite web |url=http://ngm.nationalgeographic.com/ngm/0304/feature4/online_extra2.html |archive-url=https://web.archive.org/web/20090714102812/http://ngm.nationalgeographic.com/ngm/0304/feature4/online_extra2.html |archive-date=14 July 2009 |title=Frodo: the alpha male |publisher=[[National Geographic]] |date=15 May 2002 |access-date=6 June 2009}}</ref>

A chimpanzee's strength and sharp teeth mean that attacks, even on adult humans, can cause severe injuries. This was evident after the attack and near death of former [[NASCAR]] driver St. James Davis, who was [[St. James Davis chimpanzee attack|mauled by two escaped chimpanzees]] while he and his wife were celebrating the birthday of their former pet chimpanzee.<ref>{{cite news |url=https://www.usatoday.com/news/nation/2005-03-04-chimp-attack_x.htm |title=Birthday party turns bloody when chimps attack |access-date=27 June 2006 |date=4 March 2005 |work=USATODAY |archive-date=24 May 2006 |archive-url=https://web.archive.org/web/20060524213545/http://www.usatoday.com/news/nation/2005-03-04-chimp-attack_x.htm |url-status=live }}</ref><ref>{{cite news |title=The animal within |access-date=27 June 2006 |url=https://www.washingtonpost.com/wp-dyn/content/article/2005/05/23/AR2005052301819.html |date=24 May 2005 |last=Argetsinger |first=A. |newspaper=[[The Washington Post]] |archive-date=9 November 2012 |archive-url=https://web.archive.org/web/20121109144435/http://www.washingtonpost.com/wp-dyn/content/article/2005/05/23/AR2005052301819.html |url-status=live }}</ref> Another example of chimpanzees being aggressive toward humans occurred in 2009 in [[Stamford, Connecticut]], when a {{convert|200|lb|adj=on|order=flip|sigfig=1}}, 13-year-old pet chimpanzee named [[Travis (chimpanzee)|Travis]] attacked his owner's friend, who lost her hands, eyes, nose, and part of her [[maxilla]] from the attack.<ref>{{cite news |url=http://www.nydailynews.com/news/2009/02/17/2009-02-17_911_tape_captures_chimpanzee_owners_horr-2.html |title=911 tape captures chimpanzee owner's horror as 200-pound ape mauls friend |work=[[New York Daily News]] |date=18 February 2009 |access-date=6 June 2009 |location=New York |first=E. |last=Sandoval |url-status=dead |archive-url=https://web.archive.org/web/20090219200257/http://www.nydailynews.com/news/2009/02/17/2009-02-17_911_tape_captures_chimpanzee_owners_horr-2.html |archive-date=19 February 2009}}</ref><ref>{{cite news |last=Gallman |first=S. |url=http://edition.cnn.com/2009/US/02/17/chimpanzee.attack/ |title=Chimp attack 911 call: 'He's ripping her apart' |work=CNN |date=18 February 2009 |access-date=6 June 2009 |archive-date=22 November 2019 |archive-url=https://web.archive.org/web/20191122081946/http://edition.cnn.com/2009/US/02/17/chimpanzee.attack/ |url-status=live }}</ref>

===Human immunodeficiency virus===
Two primary classes of [[human immunodeficiency virus]] (HIV) infect humans: HIV-1 and HIV-2. HIV-1 is the more virulent and easily transmitted, and is the source of the majority of HIV infections throughout the world; HIV-2 occurs mostly in west Africa.<ref name="Reeves">{{cite journal |author=Reeves, J. D. |author2=Doms, R. W. |title=Human immunodeficiency virus type 2 |journal=The Journal of General Virology |volume=83 |issue=Pt 6 |pages=1253–65 |date=June 2002 |pmid=12029140 |doi=10.1099/0022-1317-83-6-1253 |url=http://vir.sgmjournals.org/cgi/pmidlookup?view=long&pmid=12029140 |archive-url=https://archive.today/20121228095942/http://vir.sgmjournals.org/cgi/pmidlookup?view=long&pmid=12029140 |archive-date=28 December 2012 |url-status=dead |df=dmy-all |citeseerx=10.1.1.523.5120}}</ref> Both types originated in west and central Africa, jumping from other [[Zoonosis|primates to humans]]. HIV-1 has evolved from a [[simian immunodeficiency virus]] (SIVcpz) found in the subspecies ''P. t. troglodytes'' of southern [[Cameroon]].<ref name="Keele">{{cite journal |last1=Keele |first1=B. F. |display-authors=etal |title=Chimpanzee reservoirs of pandemic and nonpandemic HIV-1 |journal=Science |volume=313 |issue=5786 |pages=523–526 |date=July 2006 |pmid=16728595 |pmc=2442710 |doi=10.1126/science.1126531 |bibcode=2006Sci...313..523K}}</ref><ref name="Gao">{{cite journal |last=Gao |first=F. |display-authors=etal |title=Origin of HIV-1 in the chimpanzee ''Pan troglodytes troglodytes'' |journal=Nature |volume=397 |issue=6718 |pages=436–41 |date=February 1999 |pmid=9989410 |doi=10.1038/17130 |bibcode=1999Natur.397..436G |s2cid=4432185|doi-access=free }}</ref> [[Kinshasa]], in the Democratic Republic of Congo, has the greatest genetic diversity of HIV-1 so far discovered, suggesting the virus has been there longer than anywhere else. HIV-2 crossed species from a different strain of HIV, found in the [[sooty mangabey]] monkeys in [[Guinea-Bissau]].<ref name="Reeves"/>

==Conservation==
[[File:South Djoum Chimp.jpg|thumb|upright|right|Cameroonian chimpanzee at a rescue centre after its mother was killed by poachers]]
The chimpanzee is on the [[IUCN Red List]] as an [[endangered]] species. Chimpanzees are legally protected in most of their range and are found both in and outside [[national park]]s. Between 172,700 and 299,700 individuals are thought to be living in the wild,<ref name="iucn"/> a decrease from about a million chimpanzees in the early 1900s.<ref name="Fleur">{{cite news |last=St. Fleur |first=N. |title=U.S. will call all chimps 'endangered' |url=https://www.nytimes.com/2015/06/13/science/chimpanzees-endangered-fish-and-wildlife-service.html |archive-url=https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2015/06/13/science/chimpanzees-endangered-fish-and-wildlife-service.html |archive-date=2022-01-01 |url-access=limited |access-date=13 June 2015 |work=[[The New York Times]] |date=12 June 2015}}{{cbignore}}</ref> Chimpanzees are listed in Appendix I of the [[Convention on International Trade in Endangered Species]] (CITES), meaning that commercial international trade in wild-sourced specimens is prohibited and all other international trade (including in parts and derivatives) is regulated by the CITES permitting system.<ref name="CITES"/>

The biggest threats to the chimpanzee are habitat destruction, [[poaching]], and disease. Chimpanzee habitats have been limited by [[deforestation]] in both West and Central Africa. Road building has caused habitat degradation and fragmentation of chimpanzee populations and may allow poachers more access to areas that had not been seriously affected by humans. Although deforestation rates are low in western Central Africa, selective logging may take place outside national parks.<ref name="iucn"/>

Chimpanzees are a common target for poachers. In Ivory Coast, chimpanzees make up 1–3% of [[bushmeat]] sold in urban markets. They are also taken, often illegally, for the pet trade and are hunted for medicinal purposes in some areas. Farmers sometimes kill chimpanzees that threaten their crops; others are unintentionally maimed or killed by snares meant for other animals.<ref name="iucn"/>

Infectious diseases are a main cause of death for chimpanzees. They succumb to many diseases that afflict humans because the two species are so similar. As the human population grows, so does the risk of disease transmission between humans and chimpanzees.<ref name="iucn"/>

==See also==
{{Portal |Animals |Mammals |Primates |Africa}}
{{div col|colwidth=30}}
* {{annotated link|Anthropopithecus|''Anthropopithecus''}}
* {{annotated link|Bili ape}}
* ''[[Chimpanzee (film)|Chimpanzee]]'', 2012 documentary
* ''[[Chimp Crazy]]'', 2024 TV docuseries about chimps in the U.S. pet trade
* ''[[Chimp Empire]]'', 2023 documentary
* {{annotated link|Gombe Chimpanzee War}}
* [[Great Ape Project]]
* [[International Primate Day]]
* {{annotated link|List of individual apes}}
* ''[[One Small Step: The Story of the Space Chimps]]'', 2008 documentary
* [[Primate archaeology]]
* {{annotated link|Prostitution among animals}}

{{div col end}}

==Notes==
{{reflist|group=nb}}
{{notelist}}

==References==
{{Reflist}}

===Literature cited===
*{{cite book |last=Goodall |first=J. |author-link=Jane Goodall |year=1986 |title=The Chimpanzees of Gombe: Patterns of Behavior |publisher=The Belknap Press of Harvard University Press |isbn=978-0-674-11649-8}}

==External links==
{{Commons category|Pan troglodytes}}
{{Wikispecies|Pan troglodytes}}
* [https://web.archive.org/web/20101124001529/http://www.discoverchimpanzees.org/ DiscoverChimpanzees.org]
* [https://www.ncbi.nlm.nih.gov/projects/genome/guide/chimp/ Chimpanzee Genome resources]
* [http://pin.primate.wisc.edu/factsheets/entry/chimpanzee Primate Info Net ''Pan troglodytes'' Factsheets] {{Webarchive|url=https://web.archive.org/web/20080113091837/http://pin.primate.wisc.edu/factsheets/entry/chimpanzee |date=13 January 2008}}
* [http://ecos.fws.gov/species_profile/servlet/gov.doi.species_profile.servlets.SpeciesProfile?spcode=A06C U.S. Fish & Wildlife Service Species Profile]
* View the [http://www.ensembl.org/Pan_troglodytes/Info/Index/ ''Pan troglodytes'' genome] in [[Ensembl]]
* [https://genome.ucsc.edu/cgi-bin/hgTracks?db=panTro6&lastVirtModeType=default&lastVirtModeExtraState=&virtModeType=default&virtMode=0&nonVirtPosition=&position=chr7%3A97762313%2D125135412&hgsid=1425676799_Kj2aag12as5zsSTAwPCp502aQVkt Genome of ''Pan troglodytes'' (version Clint_PTRv2/panTro6)], via [[UCSC Genome Browser]]
* [https://www.ncbi.nlm.nih.gov/genome/202 Data of the genome of ''Pan troglodytes''], via [[NCBI]]
* [https://www.ncbi.nlm.nih.gov/assembly/GCF_002880755.1/ Data of the genome assembly of ''Pan troglodytes'' Clint_PTRv2/panTro6], via [[NCBI]]
* [http://humanorigins.si.edu/evidence/human-evolution-timeline-interactive Human Timeline (Interactive)] – [[Smithsonian Institution|Smithsonian]], [[National Museum of Natural History]] (August 2016).

{{Hominidae nav}}
{{Apes}}
{{Notable apes}}
{{Taxonbar |from=Q4126704}}
{{Authority control}}

{{DEFAULTSORT:chimpanzee}}
[[Category:Chimpanzees]]
[[Category:Tool-using mammals]]
[[Category:Primates of Africa]]
[[Category:Extant Pliocene first appearances]]
[[Category:Fauna of Sub-Saharan Africa]]
[[Category:Mammals described in 1775]]
[[Category:Taxa named by Johann Friedrich Blumenbach]]
[[Category:Articles containing video clips]]