View source for Pan (genus)

{{short description|Genus of African great apes}}
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{{Use mdy dates|date=December 2017}}
{{Automatic taxobox
| name = Chimpanzees and bonobos<ref name=MSW3>{{MSW3 Groves|pages=182–3|id=12100796}}</ref>
| fossil_range = Middle [[Pliocene]] – [[Holocene|present]]
| image = Composite image of male chimpanzee (left) and male bonobo (right).jpg
| image_caption = Members of the genus ''Pan'': chimpanzee (left) and bonobo (right)
| taxon = Pan
| authority = [[Lorenz Oken|Oken]], 1816
| type_species = ''[[Common chimpanzee|Simia troglodytes]]''
| type_species_authority = [[Johann Friedrich Blumenbach]], 1776
| subdivision_ranks = [[Species]]
| subdivision = ''[[Chimpanzee|Pan troglodytes]]''<br/>
''[[Bonobo|Pan paniscus]]''
| range_map = Pan (genus) distribution map.svg
| range_map_caption = Distribution of ''Pan troglodytes'' (common chimpanzee) and ''Pan paniscus'' (bonobo, in red)
| synonyms = * ''Troglodytes'' <small>[[Étienne Geoffroy Saint-Hilaire|E. Geoffroy]], 1812 ([[Troglodytes (bird)|preoccupied]])</small>
* ''Mimetes'' <small>Leach, 1820 ([[Noctua (moth)|preoccupied]])</small>
* ''Theranthropus'' <small>Brookes, 1828</small>
* ''Chimpansee'' <small>Voight, 1831</small>
* ''[[Anthropopithecus]]'' <small>[[Henri Marie Ducrotay de Blainville|Blainville]], 1839</small><ref>{{cite book |author=Wood, B. |display-authors=etal |title=Wiley-Blackwell Encyclopedia of Human Evolution |year=2013 |publisher=Wiley |edition=paperback |isbn=978-1-1186-5099-8}}</ref>
* ''Hylanthropus'' <small>Gloger, 1841</small>
* ''Pseudanthropus'' <small>Reichenbach, 1862</small>
* ''Engeco'' <small>Haeckel, 1866</small>
* ''Fsihego'' <small>DePauw, 1905</small>
}}

The genus '''''Pan''''' consists of two extant species: the [[chimpanzee]] and the [[bonobo]]. Taxonomically, these two ape species are collectively termed '''panins'''.<ref>{{cite book |last=Muehlenbein |first=M. P. |date=2015 |title=Basics in Human Evolution |publisher=Elsevier Science |pages=114–115 |isbn=9780128026526 }}</ref><ref>{{cite journal |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 |volume=7 |issue=608 |year=2017 |author1=Diogo, R. |author2=Molnar, J. L. |author3=Wood, B. |page= 608 |doi=10.1038/s41598-017-00548-3 |pmid= 28377592 |pmc= 5428693 |bibcode=2017NatSR...7..608D |doi-access=free |issn=2045-2322}}</ref> The two species were formerly collectively called "chimpanzees" or "chimps"; if bonobos were recognized as a separate group at all, they were referred to as "pygmy" or "gracile chimpanzees". Together with [[humans]], [[gorilla]]s, and [[orangutan]]s they are part of the family [[Hominidae]] (the great apes, or ''hominids'').  Native to [[sub-Saharan Africa]], chimpanzees and bonobos are currently both found in the [[Congo jungle]], while only the chimpanzee is also found further north in West Africa. Both species are listed as [[endangered species|endangered]] on the [[IUCN Red List of Threatened Species]], and in 2017 the [[Convention on Migratory Species]] selected the chimpanzee for special protection.<ref>{{cite news |title=Chimpanzees among 33 breeds selected for special protection |url=https://www.bbc.com/news/world-asia-41791842 |access-date=October 30, 2017 |publisher=BBC |date=October 28, 2017}}</ref>

== Chimpanzee and bonobo: comparison ==
The [[chimpanzee]] (''P. troglodytes''), which lives north of the [[Congo River]], and the bonobo (''P. paniscus''), which lives south of it, were once considered to be the same species, but since 1928 they have been recognized as distinct.<ref name="Shefferly2005">{{cite web |url= http://animaldiversity.ummz.umich.edu/site/accounts/information/Pan_troglodytes.html |title=''Pan troglodytes'' |access-date=August 11, 2007 |work= Animal Diversity Web |publisher=University of Michigan Museum of Zoology |author= Shefferly, N. |year=2005}}</ref> In addition, ''P. troglodytes'' is divided into four [[subspecies]], while ''P. paniscus'' is undivided<!--By definition, it is not possible for a species to have a single subspecies, it either has 2 or more subspecies or none-->. Based on [[genome sequencing]], these two extant ''Pan'' species diverged around one million years ago.

The most obvious differences are that chimpanzees are somewhat larger, more aggressive and male-dominated, while the bonobos are more gracile, peaceful, and female-dominated. Their hair is typically black or brown. Males and females differ in size and appearance. Both chimpanzees and bonobos are some of the most social great apes, with social bonds occurring throughout large communities. Fruit is the most important component of a chimpanzee's diet; but they will also eat vegetation, bark, honey, insects and even other chimpanzees or monkeys. They can live over 30 years in both the wild and captivity.
[[File:Pan troglodytes & Pan paniscus.jpg|thumb|right|[[Chimpanzee]] (''Pan troglodytes'') (left) and [[bonobo]] (''Pan paniscus'') (right)]]
Chimpanzees and bonobos are equally humanity's closest living relatives. They use a variety of sophisticated tools and construct elaborate sleeping nests each night from branches and foliage. Their learning abilities have been extensively studied. There may even be distinctive cultures within populations. Field studies of ''Pan troglodytes'' were pioneered by primatologist [[Jane Goodall]].

==Names==
The [[genus]] name ''Pan'' was first introduced by [[Lorenz Oken]] in 1816. While Oken did not give a rationale for his choice, it is generally thought to have been inspired by the name of the Greek god [[Pan (god)|Pan]].<ref>{{cite book |title=Sacred and Mythological Animals: A Worldwide Taxonomy |first=Yowann |last=Byghan |page=148 |publisher=McFarland |year=2020 |isbn=978-1-4766-7950-1 |url=https://books.google.com/books?id=qunaDwAAQBAJ&dq=%22the+name+Pan+for+the+genus.+from+the+Greek+god+Pan%22&pg=PA148}}</ref><ref>{{cite dictionary |author1=Beolens, B. |author2=Watkins, M. |author3=Grayson, M. |year=2009 |title=The Eponym Dictionary of Mammals |publisher=JHU Press}}</ref> An alternative ''Theranthropus'' was suggested by [[Joshua Brookes|Brookes]] 1828 and ''Chimpansee'' by [[Friedrich Siegmund Voigt|Voigt]] 1831. ''Troglodytes'' was not available, as it had been given as the name of a [[Troglodytes (bird)|genus of wren]] in 1809, for "cave-dweller", reflecting the tendency of some wrens to forage in dark crevices. The [[International Commission on Zoological Nomenclature]] adopted ''Pan'' as the only official name of the genus in 1895,<ref name="Tubbs"/> though the "cave-dweller" connection was able to be included, albeit at the species level (''Pan troglodytes'' – the common chimpanzee) for one of the two species of ''Pan''. 

The first use of the name "chimpanze" is recorded in ''[[The London Magazine]]'' in 1738,<ref>The London Magazine 465, September 1738. "A most surprising creature is brought over in the Speaker, just arrived from Carolina, that was taken in a wood at Guinea. She is the Female of the Creature which the Angolans call chimpanze, or the mockman." (cited after [[OED]])</ref> glossed as meaning "mockman" in a language of "the Angolans" (apparently from a [[Bantu language]]; reportedly modern [[Vili language|Vili (Civili)]], a Zone H Bantu language, has the comparable ''ci-mpenzi''<ref>{{cite dictionary |entry=chimpanzee |title=American Heritage Dictionary of the English Language |edition=5th |publisher=Houghton Mifflin Harcourt Publishing Company |year=2011}}</ref>). The spelling ''chimpanzee'' is found in a 1758 supplement to ''[[Cyclopædia, or an Universal Dictionary of Arts and Sciences|Chamber's Cyclopædia]]''.<ref>"Chimpanzee, the name of an Angolan animal […] In the year 1738, we had one of these creatures brought over into England." (cited after [[OED]])</ref> The [[colloquialism]] "chimp" was most likely coined some time in the late 1870s.<ref>{{OEtymD|chimpanzee}}</ref><ref>
{{cite web |url=http://dictionary.reference.com/browse/chimp |title=chimp |publisher=Dictionary.reference.com |access-date=June 6, 2009}}</ref>

The [[chimpanzee]] was named ''Simia troglodytes'' by [[Johann Friedrich Blumenbach]] in 1776. The species name ''troglodytes'' is a reference to the ''[[Troglodytae]]'' (literally "cave-goers"), an African people described by [[Greco-Roman geographers]]. Blumenbach first used it in his ''De generis humani varietate nativa liber'' ("On the natural varieties of the human genus") in 1776,<ref>{{cite book |author=Blumenbach, J. F. |year=1776 |title=De generis hvmani varietate nativa liber. Cvm figvris aeri incisis. |pages=36 |issue=37 |location=Goettingae |publisher=Vandenhoeck}}</ref><ref>{{cite web |url=http://www.animalbase.uni-goettingen.de/zooweb/servlet/AnimalBase?nav=ShowOneSpeciesTaxon&id=10352 |title=''Simia troglodytes'' |date=June 11, 2011 |author=Schultes, F. W.}}</ref> Linnaeus 1758 had already used ''Homo troglodytes'' for a hypothetical mixture of human and [[orangutan]].<ref name="Tubbs">{{cite journal |author=Tubbs, P. K. |year=1985 |title=Opinion 1368 The generic names ''Pan'' and ''Panthera'' (Mammalia, Carnivora): available as from Oken, 1816 |journal=Bulletin of Zoological Nomenclature |volume=42 |pages=365–370 |url=https://archive.org/stream/bulletinofzoolog42inte#page/364/mode/2up }} [https://www.biodiversitylibrary.org/item/44484#6 BHL] [http://biostor.org/reference/4943 BioStor] corrigendum in ''Bulletin of zoological nomenclature'', '''45''': 304. (1988) [https://archive.org/stream/bulletinofzoolog45inte#page/304/mode/2up Internet Archive] [https://www.biodiversitylibrary.org/item/44486#4 BHL]
</ref>

The bonobo, in the past also referred to as the "pygmy chimpanzee", was given the species name of ''paniscus'' by [[Ernst Schwarz (zoologist)|Ernst Schwarz]] (1929), a [[wikt:-ίσκος|Greek-style diminutive]] of the theonym ''Pan'' used by [[Cicero]].<ref>{{Cite dictionary |author1=Lewis, C. T. |author2=Short, C. |year=1879 |url=https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3DPaniscus |entry=A little Pan, a rural deity |title=A Latin Dictionary |location=Oxford |publisher=Clarendon Press}}</ref>

==Distribution and habitat==
There are two species of the genus ''Pan'', both previously called simply chimpanzees:  
# [[Chimpanzee]]s or ''[[Pan troglodytes]]'', are found almost exclusively in the heavily forested regions of Central and West Africa. With at least four commonly accepted subspecies, their population and distribution is much more extensive than the bonobos, in the past also called 'pygmy chimpanzee'.  
# Bonobos, ''[[Pan paniscus]]'', are found only in Central Africa, south of the [[Congo River]] and north of the [[Kasai River]] (a tributary of the Congo),<ref name=ancestor>{{cite book |last=Dawkins |first=R. |author-link=Richard Dawkins |title=The Ancestor's Tale |year=2004 |publisher=Houghton Mifflin |chapter=Chimpanzees |isbn=978-1-155-16265-2}}</ref> in the [[tropical and subtropical moist broadleaf forests|humid forest]] of the [[Geography of the Democratic Republic of the Congo|Democratic Republic of Congo]] of Central Africa.

{{Species table |no-note=y |genus=[[Pan (genus)|Pan]] |authority-name=[[Lorenz Oken|Oken]] |authority-year=1816 |species-count=two}}
{{Species table/row
|name=[[Bonobo]] |binomial=P. paniscus
|image=File:Apeldoorn_Apenheul_zoo_Bonobo.jpg |image-size=180px |image-alt=Black bonobo
|authority-name=[[Ernst Schwarz (zoologist)|Schwarz]] |authority-year=1929
|range=Central Africa |range-image=File:Bonobo_distribution.svg |range-image-size=180px
|size={{convert|70|–|83|cm|in|0|abbr=on}} long<ref name="AfricanMammals97"/>
|habitat=Forest<ref name="IUCNBonobo"/>
|hunting=Fruits and seeds, as well as leaves, stems, shoots, pith, bark, flowers, [[truffle]]s, fungus, and honey<ref name="IUCNBonobo"/>
|iucn-status=EN |population=Unknown
|direction={{decrease|Population declining}}<ref name="IUCNBonobo"/>
}}
{{Species table/row
|name=[[Chimpanzee]] |binomial=P. troglodytes
|image=File:Common_chimpanzee_(Pan_troglodytes_schweinfurthii)_feeding.jpg |image-size=150px |image-alt=Black chimpanzee
|authority-name=[[Johann Friedrich Blumenbach|Blumenbach]] |authority-year=1775 |authority-not-original=yes
|subspecies={{Collapsible list |expand=yes |title=Four subspecies |bullets=on
| ''P. t. ellioti'' ([[Nigeria-Cameroon chimpanzee]])
| ''P. t. schweinfurthii'' ([[Eastern chimpanzee]])
| ''P. t. troglodytes'' ([[Central chimpanzee]])
| ''P. t. verus'' ([[Western chimpanzee]])
}}
|range=Central and western Africa  |range-image=File:Pan_troglodytes_area.png |range-image-size=180px
|size={{convert|63|–|90|cm|in|0|abbr=on}} long<ref name="AfricanMammals95"/>
|habitat=Forest and savanna<ref name="IUCNChimpanzee"/>
|hunting=Fruit, leaves, stems, buds, bark, pith, seeds, and [[resin]]s, as well as insects, small vertebrates, and eggs<ref name="ADWChimpanzee"/>
|iucn-status=EN |population=Unknown
|direction={{decrease|Population declining}}<ref name="IUCNChimpanzee"/>
}}
{{Species table/end}}

==Evolutionary history==
===Evolutionary relationship===
{{Further|History of hominoid taxonomy}}
{| class="wikitable" align="center" style="margin: 1em auto 1em auto" border="1" width="350pt"
|-
! scope=col| Phylogeny of superfamily Hominoidea<ref name=Israfil_et_al>{{Cite journal |last1=Israfil |first1=H. |last2=Zehr |first2=S. M. |last3=Mootnick |first3=A. R. |last4=Ruvolo |first4=M. |last5=Steiper |first5=M. E. |title=Unresolved molecular phylogenies of gibbons and siamangs (Family: Hylobatidae) based on mitochondrial, Y-linked, and X-linked loci indicate a rapid Miocene radiation or sudden vicariance event |doi=10.1016/j.ympev.2010.11.005 |journal=Molecular Phylogenetics and Evolution |volume=58 |issue=3 |pages=447–455 |year=2011 |pmid=21074627 |pmc=3046308 |bibcode=2011MolPE..58..447I |url=http://www.gibboncenter.org/publications/MolecularPhylogeneticsIsrafil_etal_2011_MPE.pdf |archive-url=https://web.archive.org/web/20120507084656/http://www.gibboncenter.org/publications/MolecularPhylogeneticsIsrafil_etal_2011_MPE.pdf |url-status=dead |archive-date=2012-05-07}}</ref>{{rp|at=Fig. 4}}
|-
|
{{Clade
|label1=&nbsp;Hominoidea
|1={{Clade
   |1=gibbons&nbsp;(family&nbsp;Hylobatidae)
   |2={{Clade
      |1=orangutans&nbsp;(genus ''Pongo'')
      |2={{Clade
         |1=gorillas&nbsp;(genus ''Gorilla'')
         |2={{Clade
            |1=humans&nbsp;(genus&nbsp;''Homo'')
            |2='''chimpanzees&nbsp;(genus&nbsp;''Pan'')'''
            }}
         }}
      }}
   }}
}}
|}

The genus ''Pan'' is part of the subfamily [[Homininae]], to which humans also belong. The lineages of chimpanzees{{dubious|Chimp or genus Pan, incl. bonobo? Question valid for entire "Evol. hist." paragraph.|date=August 2016}} and humans [[chimpanzee–human last common ancestor|separated]] in a process of [[speciation]] between roughly five to twelve million years ago,<ref>{{cite journal |last1=Wakeley |first1=J. |year=2008 |title=Complex speciation of humans and chimpanzees |journal=Nature |volume=452 |issue=7184 |pages=E3–4 |doi=10.1038/nature06805 |pmid=18337768 |bibcode=2008Natur.452....3W |s2cid=4367089}}</ref> making them humanity's closest living relative.<ref>{{cite magazine |url=http://www.scientificamerican.com/article/latest-theory-human-body-hair/ |title=What is the latest theory of why humans lost their body hair? Why are we the only hairless primate? |date=June 4, 2007 |author=Pagel, M. |magazine=[[Scientific American]]}}</ref> Research by [[Mary-Claire King]] in 1973 found 99% identical [[DNA]] between human beings and chimpanzees.<ref>{{cite thesis |author=King, M.-C. |year=1973 |title=Protein polymorphisms in chimpanzee and human evolution |type=Doctoral dissertation |publisher=University of California, Berkeley}}</ref> For some time, research modified that finding to about 94%<ref name=ns>{{cite magazine |url=http://www.scientificamerican.com/article.cfm?id=human-chimp-gene-gap-wide |date=December 19, 2006 |title=Humans and chimps: close but not that close |magazine=[[Scientific American]] |author=Minkel, J. R.}}</ref> commonality, with some of the difference occurring in [[noncoding DNA]], but more recent knowledge puts the difference in DNA between humans, chimpanzees and [[bonobo]]s at just about 1%–1.2% again.<ref name=sciam>{{cite magazine |first = K. |last = Wong |title = Tiny genetic differences between humans and other primates pervade the genome |url=https://www.scientificamerican.com/article/tiny-genetic-differences-between-humans-and-other-primates-pervade-the-genome/ |magazine=[[Scientific American]] |date=September 1, 2014}}</ref><ref name="science2">{{cite news |first=A. |last=Gibbons |title=Bonobos join chimps as closest human relatives |publisher=[[American Association for the Advancement of Science|Science/AAAS]] |date=June 13, 2012}}</ref>

===Fossils===
The chimpanzee{{dubious|Chimp or genus Pan, incl. bonobo? Question valid for entire "Fossils" paragraph ("Pan" shows up in 2nd half).|date=August 2016}} fossil record has long been absent and thought to have been due to the [[preservation bias]] in relation to their environment. However, in 2005, chimpanzee fossils were discovered and described by [[Sally McBrearty]] and colleagues. Existing chimpanzee populations in West and Central Africa are separate from the major [[human fossil]] sites in East Africa; however, chimpanzee fossils have been reported from [[Kenya]], indicating that both humans and members of the ''Pan'' clade were present in the [[East African Rift]] Valley during the [[Middle Pleistocene]].<ref name=firstfossil>{{cite journal |title=First fossil chimpanzee |last1=McBrearty |first1=S. |last2=Jablonski |first2=N. G. |journal=Nature |date=2005 |volume=437 |issue=7055 |pages=105–8 |pmid=16136135 |doi=10.1038/nature04008 |bibcode=2005Natur.437..105M |s2cid=4423286 }}</ref>

==Anatomy and physiology==
{{Multiple image |header= |caption_align=center |align=left |width= |direction=horizontal |image1=Man&chimpbrains.png |caption1=Human and chimpanzee skulls and brains (not to scale), as illustrated in [[Paul Gervais|Gervais]]' ''Histoire naturelle des mammifères'' |width1=200 |image2=Chimpanzee and human brain scaled to the same size Thomas Henry Huxley.png |caption2=The chimpanzee's brain on the left and the human brain on the right have been scaled to the same size to show the relative proportions of their parts. These drawings were in a book made in 1904 by [[Thomas Henry Huxley]].<ref>{{cite book |last=Huxley |first=T. H. |year=1904 |hdl=2027/uva.x000705538 |url=https://babel.hathitrust.org/cgi/pt?id=uva.x000705538&view=1up&seq=98&skin=2021&q1=brain |title=Man's Place in Nature |series=The new science library, v. 5 |pages=78 |publisher=J. A. Hill and Company}}</ref> |width2=320 |footer= }}
The chimpanzee's arms are longer than its legs. The male common chimp stands up to {{convert|1.2|m|ft|abbr=on}} high. Male adult wild chimps weigh between 40 and 60&nbsp;kg<ref>{{Cite journal |last1=Uehara |first1=S. |last2=Nishida |first2=T. |date=March 1, 1987 |title=Body weights of wild chimpanzees (''Pan troglodytes schweinfurthii'') of the Mahale Mountains National Park, Tanzania |journal=American Journal of Physical Anthropology |volume=72 |issue=3 |pages=315–321 |doi=10.1002/ajpa.1330720305 |issn=0002-9483 |pmid=3578495}}</ref><ref name=":0">{{Cite book |title=Jane Goodall: Primatologist and Animal Activist |last=Jankowski |first=C. |publisher=Compass Point Books |year=2009 |isbn=9780756540548 |location=Mankato, MN, USA |pages=14 |oclc=244481732}}</ref><ref>{{Cite news |url=http://www.nationalgeographic.com/animals/mammals/c/chimpanzee/ |archive-url=https://web.archive.org/web/20161018065027/http://www.nationalgeographic.com/animals/mammals/c/chimpanzee/ |url-status=dead |archive-date=October 18, 2016 |title=Chimpanzee |date=May 10, 2011 |work=nationalgeographic.com |access-date=2017-03-21 |publisher=National Geographic}}</ref> with females weighing between 27 and 50&nbsp;kg.<ref name=":0" /> When extended, the common chimp's long arms span one and a half times the body's height.<ref name="Shefferly2005"/> The bonobo is slightly shorter and thinner than the common chimpanzee, but has longer limbs. In trees, both species climb with their long, powerful arms; on the ground, chimpanzees usually [[knuckle-walking|knuckle-walk]], or walk on all fours, clenching their fists and supporting themselves on the knuckles. Chimpanzees are better suited for walking than orangutans, because the chimp's feet have broader soles and shorter toes. The bonobo has proportionately longer upper limbs and walks upright more often than does the common chimpanzee. Both species can walk upright on two legs when carrying objects with their hands and arms.

[[File:Comparison of size of chimpanzee (Pan troglodytes) and human.svg|thumb|Comparison of size of adult chimpanzee and adult human.]]
The chimpanzee is tailless; its coat is dark; its face, fingers, palms of the hands, and soles of the feet are hairless. The exposed skin of the face, hands, and feet varies from pink to very dark in both species, but is generally lighter in younger individuals and darkens with maturity. A University of Chicago Medical Centre study has found significant genetic differences between chimpanzee populations.<ref>{{Cite news |title=Gene study shows three distinct groups of chimpanzees |date=April 20, 2007 |url=http://www.eurekalert.org/pub_releases/2007-04/uocm-gss042007.php |work=EurekAlert |access-date=2007-04-23 }}</ref> A bony shelf over the eyes gives the forehead a receding appearance, and the nose is flat. Although the jaws protrude, a chimp's lips are thrust out only when it pouts.

The brain of a chimpanzee has been measured at a general range of 282–500&nbsp;cm<sup>3</sup>.<ref>{{cite book |author=Tobias, P. |year=1971 |url=https://archive.org/details/braininhominidev38tobi |title=The Brain in Hominid Evolution |location=New York, USA |publisher=Columbia University Press |hdl=2246/6020|isbn=9780231035187 }}{{cite thesis |author=Schoenemann, P. T. |year=1997 |url=http://www.indiana.edu/~brainevo/publications/dissertation/Dissertation_title.htm |title=An MRI study of the relationship between human neuroanatomy and behavioral ability |type=PhD thesis |publisher=University of California, Berkeley}}</ref> The human brain, in contrast, is about three times larger, with a reported average volume of about 1330&nbsp;cm<sup>3</sup>.<ref>{{cite journal |doi=10.1146/annurev.anthro.35.081705.123210 |title=Evolution of the size and functional areas of the human brain |year=2006 |last1=Schoenemann |first1=P. T. |journal=Annual Review of Anthropology |volume=35 |pages=379–406 |issue=1 |quote=Modern human brain sizes vary widely, but average ~1330 cc (Dekaban 1978, Garby ''et al.'' 1993, Ho ''et al.'' 1980a, Pakkenberg & Voigt 1964)}}</ref>

{{Anchor|Testicles}}
Chimpanzees reach [[puberty]] between the age of eight and ten years.<ref>{{Cite book| url=https://oxfordre.com/psychology/display/10.1093/acrefore/9780190236557.001.0001/acrefore-9780190236557-e-50 | doi=10.1093/acrefore/9780190236557.013.50 | chapter=Cognitive Development in Chimpanzees | title=Oxford Research Encyclopedia of Psychology | date=2021 | last1=Matsuzawa | first1=Tetsuro | isbn=978-0-19-023655-7 }}</ref> A chimpanzee's [[testicle]]s are unusually large for its body size, with a combined weight of about {{convert|4|oz|abbr=on}} compared to a gorilla's {{convert|1|oz|abbr=on}} or a human's {{convert|1.5|oz}}. This relatively great size is generally attributed to [[sperm competition]] due to the [[Polygynandry|polygynandrous]] nature of chimpanzee [[Animal sexual behaviour|mating behaviour]].<ref name=rat_behavior>{{cite web |url=http://www.ratbehavior.org/testicles.htm |work=ratbehavior.org |title=Why are rat testicles so big? |date=2003–2004 |access-date=September 1, 2009}}</ref><ref>{{cite web |last1=Maslin |first1=M. |title=Why did humans evolve big penises but small testicles? |url=http://theconversation.com/why-did-humans-evolve-big-penises-but-small-testicles-71652 |website=theconversation.com |access-date=22 December 2018 |date=25 January 2017}}</ref>

==Longevity==
In the wild, chimpanzees live to their 30s,<ref>{{Cite journal |doi=10.1073/pnas.1612191113 |pmid=27872299 |pmc=5137748 |title=The emergence of longevous populations |journal=[[Proceedings of the National Academy of Sciences]] |volume=113 |issue=48 |pages=E7681–E7690 |year=2016 |last1=Colchero |first1=F. |last2=Rau |first2=R. |last3=Jones |first3=O. R. |display-authors=3 |last4=Barthold |first4=Julia A. |last5=Conde |first5=Dalia A. |last6=Lenart |first6=Adam |last7=Nemeth |first7=Laszlo |last8=Scheuerlein |first8=Alexander |last9=Schoeley |first9=Jonas |last10=Torres |first10=Catalina |last11=Zarulli |first11=Virginia |last12=Altmann |first12=Jeanne |last13=Brockman |first13=Diane K. |last14=Bronikowski |first14=Anne M. |last15=Fedigan |first15=Linda M. |last16=Pusey |first16=Anne E. |last17=Stoinski |first17=Tara S. |last18=Strier |first18=Karen B. |last19=Baudisch |first19=Annette |last20=Alberts |first20=Susan C. |last21=Vaupel |first21=James W.|bibcode=2016PNAS..113E7681C |doi-access=free }}</ref><ref>{{cite journal |doi=10.1002/1098-2361(2000)19:2<111::AID-ZOO2>3.0.CO;2-5 |title=Advanced age influences chimpanzee behavior in small social groups |journal=Zoo Biology |volume=19 |issue=2 |pages=111–119 |year=2000 |last1=Baker |first1=K. C. |url=http://www.chimpcare.org/assets/forums/4_ftp.pdf |citeseerx=10.1.1.694.6985}}</ref> while some captured chimps have reached an age of [[Oldest apes|70 years and older]].<ref>{{cite web |url=http://edition.cnn.com/2012/04/21/us/oldest-chimpanzee-in-captivity/ |title=Meet one of the oldest chimpanzees in captivity |first=K. |last=Segal |website=CNN |date=April 21, 2012 |access-date=October 7, 2017}}</ref>

===Muscle strength===
<!--No info available on bonobos?-->
Chimpanzees{{dubious|Chimp or genus Pan, incl. bonobo? Question valid for entire paragraph.|date=August 2016}} are known for possessing great amount of muscle strength, especially in their arms. However, compared to humans the amount of strength reported in media and popular science is greatly exaggerated with numbers of four to eight times the muscle strength of a human. These numbers stem from two studies in 1923 and 1926 by a biologist named John Bauman.<ref>{{cite journal |year=1923 |jstor=6455 |title=The strength of the chimpanzee and orang |author=Bauman, J. E. |journal=The Scientific Monthly |volume=16 |issue=4 |pages=432–439 |bibcode=1923SciMo..16..432B}}</ref><ref>{{cite journal |jstor=1373587 |title=Observations on the strength of the chimpanzee and its implications |doi=10.2307/1373587 |volume=7 |pages=1–9 |author=Bauman, J. E. |journal=Journal of Mammalogy |issue=1 |year=1926}}</ref> These studies were refuted in 1943 and an adult male chimpanzee was found to pull about the same weight as an adult man.<ref>{{cite journal |jstor=1374806 |title=The bodily strength of chimpanzees |volume=24 |pages=224–228 |author=Finch, G. |journal=Journal of Mammalogy |issue=2 |year=1943 |doi=10.2307/1374806 }}</ref> Corrected for their smaller body sizes, chimpanzees were found to be stronger than humans but not anywhere near four to eight times. In the 1960s these tests were repeated and chimpanzees were found to have twice the strength of a human when it came to pulling weights. The reason for the higher strength seen in chimpanzees compared to humans are thought to come from longer skeletal muscle fibers that can generate twice the work output over a wider range of motion compared to skeletal muscle fibers in humans.

==Behaviour==
It is suspected that human observers can influence chimpanzee behaviour.{{Vague|date=April 2020}}  For this reason researchers sometimes prefer camera traps and remote microphones rather than human observers.<ref>{{Cite news |url=https://www.bbc.co.uk/news/science-environment-40348890 |title=Watched chimps change their hunting habits |last=Gill |first=V. |date=June 23, 2017 |work=BBC News |access-date=2017-06-23}}</ref>

===Chimpanzee vs. bonobo===
[[File:Bonobo 009.jpg|thumb|Bonobo]]
[[File:Pan troglodytes-female-TobuZoo2012.ogv|thumb|(video) Female chimpanzee at Tobu Zoo in [[Saitama Prefecture|Saitama]], Japan]]

Anatomical differences between the common chimpanzee and the [[bonobo]] are slight. Both are [[omnivores|omnivorous]] adapted to a mainly [[frugivorous]] [[diet (nutrition)|diet]].<ref name=Goodall1986>{{cite book |last=Goodall |first=J. |author-link=Jane Goodall |year=1986 |title=The Chimpanzees of Gombe: Patterns of Behavior |publisher=Belknap Press of Harvard University Press |isbn=978-0-674-11649-8 |url=https://archive.org/details/chimpanzeesofgom00good }}</ref><ref>{{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=April 22, 2013 |date=2009-07-04 |archive-date=November 18, 2019 |archive-url=https://web.archive.org/web/20191118084847/http://www.allaboutwildlife.com/what-do-chimps-eat |url-status=dead }}</ref> Yet sexual and social behaviours are markedly different. The common chimpanzee has a troop culture based on beta males led by an [[alpha male]], and highly complex social relationships. The bonobo, on the other hand, has [[egalitarian]], [[nonviolent]], [[matriarchal]], [[Animal sexual behaviour#Bonobo|sexually receptive behaviour]].<ref>{{cite web |url=http://www.bio.davidson.edu/people/vecase/Behavior/Spring2004/laird/Social%20Organization.htm |title=Social organization |author=Laird, C. |access-date=2008-03-10 |work=Davidson College |date=Spring 2004 |url-status=dead |archive-url= https://web.archive.org/web/20070209112721/http://www.bio.davidson.edu/people/vecase/Behavior/Spring2004/laird/Social%20Organization.htm |archive-date=February 9, 2007}}</ref> Bonobos frequently have sex, sometimes to help prevent and resolve conflicts. Different groups of chimpanzees also have different cultural behaviour with preferences for types of tools.<ref>{{cite web |url=http://www.janegoodall.com/chimp_central/chimpanzees/behavior/default.asp |title=Chimp behavior |access-date=2007-08-11 |publisher=Jane Goodall Institute |archive-url=https://web.archive.org/web/20070927045315/http://www.janegoodall.com/chimp_central/chimpanzees/behavior/default.asp |archive-date=September 27, 2007}}</ref> The common chimpanzee tends to display greater aggression than does the bonobo.<ref>{{Cite book |chapter-url=https://books.google.com/books?id=lDP4TPccgC8C&pg=PA30 |title=Our Inner Ape |chapter=Apes in the family |last=de Waal |first=F. |author-link=Frans de Waal |isbn=978-1-59448-196-3 |year=2006 |publisher=Riverhead Books |location=New York |url=https://archive.org/details/isbn_9781594481963}}</ref> The average captive chimpanzee sleeps 9 hours and 42 minutes per day.<ref>{{cite magazine |last1=Holland |first1=J. S. |year=2011 |title=40 winks? |magazine=National Geographic |volume=220 |issue=1}}</ref>

Contrary to what the scientific name (''Pan'' ''[[Common chimpanzee|troglodytes]]'') may suggest, chimpanzees do not typically spend their time in caves, but there have been reports of some of them seeking refuge in caves because of the heat during daytime.<ref name="LiveScience">{{cite web |author=Choi, C. Q. |date=April 11, 2007 |url=http://www.livescience.com/1404-chimps-spotted-caves-early-humans.html |title=Chimps spotted using caves, like early humans |publisher=[[LiveScience]]}}</ref>

===Chimpanzees===

====Social structure====
<!--No info on bonobos available?-->
Chimpanzees live in large multi-male and multi-female [[social group]]s, which are called communities. Within a community, the position of an individual and the influence the individual has on others dictates a definite [[social hierarchy]]. Chimpanzees live in a leaner hierarchy wherein more than one individual may be dominant enough to dominate other members of lower rank. Typically, a dominant male is referred to as the [[alpha male]]. The alpha male is the highest-ranking male that controls the group and maintains order during disputes. In chimpanzee society, the 'dominant male' sometimes is not the largest or strongest male but rather the most manipulative and political male that can influence the goings on within a group. Male chimpanzees typically attain dominance by cultivating allies who will support that individual during future ambitions for power. The alpha male regularly displays by puffing his normally slim coat up to increase view size and charge to seem as threatening and as powerful as possible; this behaviour serves to intimidate other members and thereby maintain power and authority, and it may be fundamental to the alpha male's holding on to his status. Lower-ranking chimpanzees will show respect by submissively gesturing in [[body language]] or reaching out their hands while grunting. Female chimpanzees will show deference to the alpha male by presenting their hindquarters.

[[File:Gombe Stream NP gegenseitiges Lausen.jpg|thumb|Common chimpanzees in [[Gombe Stream National Park]]]]
Female chimpanzees also have a hierarchy, which is influenced by the position of a female individual within a group. In some chimpanzee communities, the young females may inherit high status from a high-ranking mother. Dominant females will also ally to dominate lower-ranking females: whereas males mainly seek dominant status for its associated mating privileges and sometimes violent domination of subordinates, females seek dominant status to acquire resources such as food, as high-ranking females often have first access to them. Both genders acquire dominant status to improve social standing within a group.

Community female acceptance is necessary for alpha male status; females must ensure that their group visits places that supply them with enough food. A group of dominant females will sometimes oust an alpha male which is not to their preference and back another male, in whom they see potential for leading the group as a successful alpha male.

The mating system within each community is [[polygynandry|polygynandrous]], with each male and female possibly having multiple sexual partners.<ref>{{cite journal |last1=Georgiev |first1=A. V. |last2=Russell |first2=A. F. |last3=Thompson |first3=M. E. |last4=Otali |first4=E. |last5=Muller |first5=M. N. |last6=Wrangham |first6=R. W. |author6-link=Richard Wrangham |year=2014 |title=The foraging costs of mating effort in male chimpanzees (''Pan troglodytes schweinfurthii'') |journal=International Journal of Primatology |volume=35 |issue=3–4 |pages=725–745 |url=https://www.researchgate.net/publication/264334254 |doi=10.1007/s10764-014-9788-y |s2cid=17692801}}</ref>

====Intelligence====
{{further|Primate cognition}}
[[File:1911 EB Chimpanzee Brain.png|thumb|right|340px|Diagram of brain – topography of the main groups of foci in the motor field of chimpanzee]]
<!--No info available on bonobos?-->
Chimpanzees make tools and use them to acquire foods and for social displays; they have sophisticated hunting strategies requiring cooperation, influence and rank; they are status conscious, manipulative and capable of deception; they can learn to use symbols and understand aspects of human language including some relational [[Syntax (logic)|syntax]], concepts of number and numerical sequence;<ref>{{cite web |url=http://www.indiana.edu/~origins/teach/A105/lectures/A105L12.html |title=Chimpanzee intelligence |publisher=[[Indiana University]] |access-date=2008-03-24 |date=February 23, 2000 |archive-date=September 17, 2016 |archive-url=https://web.archive.org/web/20160917161331/http://www.indiana.edu/~origins/teach/A105/lectures/A105L12.html |url-status=dead }}</ref> and they are capable of spontaneous planning for a future state or event.<ref>{{Cite journal |last=Osvath |first=M. |date=March 10, 2009 |title=Spontaneous planning for future stone throwing by a male chimpanzee |journal=Current Biology |volume=19 |issue=5 |pages=R190–1 |doi=10.1016/j.cub.2009.01.010 |pmid=19278627 |s2cid=1669313 |doi-access=free|bibcode=2009CBio...19.R190O }}</ref>

====Tool use====
[[File:Chimpanzee and stick.jpg|thumb|Common chimpanzee using a stick]]
<!--No info available on bonobos?-->

In October 1960, [[Jane Goodall]] observed the use of tools among chimpanzees{{dubious|Chimp or genus Pan, incl. bonobo? Question valid for entire paragraph.|date=August 2016}}. Recent research indicates that chimpanzees' use of [[stone tool]]s dates back at least 4,300 years (about 2,300 BC).<ref>{{cite journal |author1=Mercader, J. |author2=Barton, H. |author3=Gillespie, J. |title=4,300-year-old chimpanzee sites and the origins of percussive stone technology |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=104 |issue=9 |pages=3043–8 |year=2007 |pmid=17360606 |pmc=1805589 |doi=10.1073/pnas.0607909104 |display-authors=etal |bibcode= 2007PNAS..104.3043M|doi-access=free }}</ref> One example of chimpanzee tool usage behavior includes the use of a large stick as a tool to dig into termite mounds, and the subsequent use of a small stick altered into a tool that is used to "fish" the termites out of the mound.<ref>{{cite magazine |author=Bijal, T. |title=Chimps shown using not just a tool but a "tool kit" |url=http://news.nationalgeographic.com/news/2004/10/1006_041006_chimps.html |archive-url=https://web.archive.org/web/20041010065204/http://news.nationalgeographic.com/news/2004/10/1006_041006_chimps.html |url-status=dead |archive-date=October 10, 2004 |magazine=National Geographic |date=September 6, 2004}}</ref> Chimpanzees are also known to use smaller stones as hammers and a large one as an anvil in order to break open nuts.<ref>{{cite journal |author=Carvalho, S. |title=Chaînes Opératoires and resource-exploitation strategies in chimpanzee (''Pan troglodytes'') nut cracking |journal=Journal of Human Evolution |volume=55 |pages=148–163 |year=2008 |doi=10.1016/j.jhevol.2008.02.005 |pmid=18359504 |issue=1 |bibcode=2008JHumE..55..148C |display-authors=etal |hdl=10316/3758 |hdl-access=free}}</ref>

In the 1970s, reports of chimpanzees using rocks or sticks as weapons were anecdotal and controversial.<ref>{{cite book |doi=10.1016/S0065-3454(08)60157-6 |title=Tool-using in primates and other vertebrates |volume=3 |pages=195–249 |series=Advances in the Study of Behavior |year=1971 |last1=Van Lawick-Goodall |first1=J. |isbn=9780120045037 |editor1=Lehrman, D. S. |editor2=Hinde, R. A. |editor3=Shaw, E. |place=New York, USA |publisher=Academic Press}}</ref> However, a 2007 study claimed to reveal the use of spears, which common chimpanzees in [[Senegal]] sharpen with their teeth and use to stab and pry [[Senegal bushbaby|Senegal bushbabies]] out of small holes in trees.<ref>{{cite web | author=Fox, M. |title=Hunting chimps may change view of human evolution |url=https://news.yahoo.com/s/nm/20070222/sc_nm/chimps_hunting_dc |access-date=2007-02-22 |date=February 22, 2007 |publisher=Yahoo News |archive-url=https://web.archive.org/web/20070224115149/http://news.yahoo.com/s/nm/20070222/sc_nm/chimps_hunting_dc |archive-date=February 24, 2007}}</ref><ref>{{cite web |url=http://www.iastate.edu/~nscentral/news/2007/feb/chimpstools.shtml |title=ISU anthropologist's study is first to report chimps hunting with tools |access-date=August 11, 2007 |date=February 22, 2007 |publisher=Iowa State University News Service |archive-url=https://web.archive.org/web/20070816143403/http://www.iastate.edu/%7Enscentral/news/2007/feb/chimpstools.shtml |archive-date=August 16, 2007 |url-status=dead }}</ref>

Prior to the discovery of tool use by chimpanzees, humans were believed to be the only [[species]] to make and use tools; however, several other [[Tool use by animals|tool-using species]] are now known.<ref>{{cite web |url=http://www.livescience.com/animals/070212_chimp_tools.html |title=Chimps learned tool use long ago without human help |access-date=2007-08-11 |last=Whipps |first=H. |date=February 12, 2007 |publisher=[[LiveScience]]}}</ref><ref>{{cite web |url=http://janegoodall.net/chimp_central/chimpanzees/gombe/tool.asp |title=Tool use |access-date=2007-08-11 |publisher=Jane Goodall Institute |archive-url=https://web.archive.org/web/20070520045747/http://www.janegoodall.net/chimp_central/chimpanzees/gombe/tool.asp |archive-date=May 20, 2007}}</ref>

====Nest-building====
{{Further|Nest-building in primates}}Nest-building, sometimes considered to be a form of tool use, is seen when chimpanzees construct arboreal night nests by lacing together branches from one or more trees to build a safe, comfortable place to sleep; infants learn this process by watching their mothers. The nest provides a sort of mattress, which is supported by strong branches for a foundation, and then lined with softer leaves and twigs; the minimum diameter is {{convert|5|m|ft}} and may be located at a height of {{convert|3|to|45|m|ft|-1}}. Both day and night nests are built, and may be located in groups.<ref name="WranghamSciences1996">{{cite book |last=Wrangham |first=R. W. |author-link=Richard Wrangham |title=Chimpanzee cultures |url=https://books.google.com/books?id=IzBIHPeE45IC&pg=PA115 |year=1996 |publisher=Chicago Academy of Sciences, Harvard University Press |isbn=978-0-674-11663-4 |pages=115–125}}</ref> A study in 2014 found that the [[Cynometra alexandri|muhimbi]] tree is favoured for nest building by chimpanzees in Uganda due to its physical properties, such as bending strength, inter-node distance, and leaf surface area.<ref>{{cite journal |last1=Samson |first1=D. R. |last2=Hunt |first2=K. D. |title=Chimpanzees preferentially select sleeping platform construction tree species with biomechanical properties that yield stable, firm, but compliant nests |journal=PLOS ONE |doi=10.1371/journal.pone.0095361 |year=2014 |volume=9 |issue=4 |pages=e95361 |pmid=24740283 |pmc=3989313 |bibcode=2014PLoSO...995361S |doi-access=free }}</ref>

====Altruism and emotivity====
[[File:Chimpanzee mom and baby cropped.jpg|left|thumb|upright|Chimpanzee mother and baby]]
<!--No info available on bonobos?-->

Studies have shown chimpanzees engage in apparently [[altruism|altruistic]] behaviour within groups.<ref>{{cite web |url=https://www.sciencedaily.com/releases/2007/06/070625085134.htm |title=Human-like altruism shown in chimpanzees |access-date=August 11, 2007 |date=June 25, 2007 |work=Science Daily}}</ref><ref>{{Cite journal |last=Bradley |first=B. |date=1999 |title=Levels of selection, altruism, and primate behavior |journal=The Quarterly Review of Biology |volume=74 |issue=2 |pages=171–194 |doi=10.1086/393070 |pmid=10412224 |s2cid=11432622}}</ref> Some researchers have suggested that chimpanzees are indifferent to the welfare of unrelated group members,<ref name="Silk_etal2005">{{cite journal |author1-link=Joan Silk |last1=Silk |first1=J. B. |last2=Brosnan |first2=S. F. |last3=Vonk |first3=J. |title=Chimpanzees are indifferent to the welfare of unrelated group members |journal=Nature |volume=437 |issue=7063 |pages=1357–9 |year=2005 |pmid=16251965 |doi=10.1038/nature04243 |display-authors=etal |bibcode=2005Natur.437.1357S |s2cid=8440378}}</ref> but a more recent study of wild chimpanzees found that both male and female adults would adopt orphaned young of their group. Also, different groups sometimes share food, form coalitions, and cooperate in hunting and border patrolling.<ref>{{cite journal |author1=Boesch, C. |author2=Bolé, C. |author3=Eckhardt, N. |author4=Boesch, H. |title=Altruism in forest chimpanzees: the case of adoption |year=2010 |page=e8901 |journal=PLOS ONE |volume=5 |issue=1 |doi = 10.1371/journal.pone.0008901 |editor1-last=Santos |editor1-first=L. |pmid=20111704 |pmc=2811728 |bibcode=2010PLoSO...5.8901B|doi-access=free }}</ref> Sometimes, chimpanzees have adopted young that come from unrelated groups. And in some rare cases, even male chimpanzees have been shown to take care of abandoned infant chimpanzees of an unrelated group, though in most cases they would kill the infant.<ref name="zuberbühler">{{cite journal |last1=Zuberbühler |first1=K. |last2=Langergraber |first2=K. |last3=Schel |first3=A. M. |last4=Hobaiter |first4=C. |title='Adoption' by maternal siblings in wild chimpanzees |journal=PLOS ONE |year=2014 |volume=9 |issue=8 |pages=e103777 |doi=10.1371/journal.pone.0103777 |pmid=25084521 |pmc=4118915 |bibcode=2014PLoSO...9j3777H |issn=1932-6203|doi-access=free }}</ref>

According to a literature summary by James W. Harrod, evidence for [[Emotion in animals#Primates|chimpanzee emotivity]] includes display of [[mourning]]; "incipient [[romantic love]]"; "rain dances"{{refn|group=Note|''At the onset of thunderstorms or sudden wind gusts chimpanzee males' hair bristles; they perform spectacular aggression displays, charging, waying back and forth, breaking off and brandishing branches. Such displays are performed more often toward the beginning of the rainy season... Rain dance is habitual at Tai Forest and Budongo and customary at Gombe, Mahale-M, Mahale-K and Kibale (Whiten et al 1999).''<ref name=JHarrod>{{cite web |url=http://www.originsnet.org/chimpspiritdatabase.pdf |title=Appendices for chimpanzee spirituality: a concise synthesis of the literature |author=Harrod, J. |date=May 10, 2007 |access-date=January 28, 2011 |url-status=dead |archive-url=https://web.archive.org/web/20080527230019/http://www.originsnet.org/chimpspiritdatabase.pdf |archive-date=May 27, 2008}}</ref>}}; appreciation of natural beauty (such as a sunset over a lake); curiosity and respect towards other wildlife (such as the [[Pythonidae|python]], which is neither a threat nor a food source to chimpanzees); altruism toward other species (such as feeding turtles); and [[animism]], or "pretend play", when chimpanzees cradle and [[Social grooming|groom]] rocks or sticks.<ref name=JHarrod/>

====Communication between chimpanzees====
<!--No info available on bonobos?-->
Chimpanzees communicate in a manner that is similar to that of human nonverbal communication, using vocalizations, hand gestures, and facial expressions. There is some evidence that they can recreate human speech.<ref>Archived at [https://ghostarchive.org/varchive/youtube/20211211/y4Z0xn4pYSY Ghostarchive]{{cbignore}} and the [https://web.archive.org/web/20121126023820/http://www.youtube.com/watch?v=y4Z0xn4pYSY&gl=US&hl=en Wayback Machine]{{cbignore}}: {{cite AV media |url=https://www.youtube.com/watch?v=y4Z0xn4pYSY |title=Chimpanzee talking |date=August 17, 2007 |work=YouTube |access-date=August 28, 2015}}{{cbignore}}</ref> Research into the chimpanzee brain has revealed that when chimpanzees communicate, an area in the brain is activated which is in the same position as the language center called [[Broca's area]] in human brains.<ref>{{cite episode |title=Communication |series=Evolve |series-link=Evolve (TV series) |airdate=2008-09-14 |season=1 |number=7}}</ref>

====Aggression====
<!--No info available on bonobos?-->
Adult common chimpanzees, particularly males, can be very aggressive. They are highly territorial and are known to kill others of their species.<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=February 19, 2009 |title=Why the Stamford chimp attacked |magazine=[[TIME]] |date=February 18, 2009 |access-date=2009-06-06}}</ref>

[[File:Gombe Stream NP Beute.jpg|thumb|Common chimpanzee with hunted bushbuck on a tree in Gombe Stream National Park]]

====Hunting====
<!--No info available on bonobos?-->
Chimpanzees also engage in targeted hunting of smaller primates, such as the [[red colobus]]<ref name="chimpanzee predation on the red colobus">{{cite journal |author=Teelen, S. |title=Influence of chimpanzee predation on the red colobus population at Ngogo, Kibale National Park, Uganda |journal=Primates |volume=49 |issue=1 |pages=41–9 |year=2008 |pmid=17906844 |doi=10.1007/s10329-007-0062-1 |s2cid=19914188}}</ref> and [[Galago|bush babies]].<ref name="Gibbons2007">{{cite journal |author=Gibbons, A. |title=Primate behavior. Spear-wielding chimps seen hunting bush babies |journal=Science |volume=315 |issue=5815 |page=1063 |year=2007 |pmid=17322034 |doi=10.1126/science.315.5815.1063 |s2cid=40430973}}</ref><ref name="PruetzBertolani2007">{{cite journal |author1=Pruetz, J. D. |author2=Bertolani, P. |title=Savanna chimpanzees, ''Pan troglodytes verus'', hunt with tools |journal=Current Biology |volume=17 |issue=5 |pages=412–7 |year=2007 |pmid=17320393 |doi=10.1016/j.cub.2006.12.042 |s2cid=16551874 |doi-access=free|bibcode=2007CBio...17..412P }}</ref> Males who acquire the meat may share it with females to have sex or for grooming.<ref name="meat is frequently used as a social tool">{{cite journal |last1=Hockings |first1=K. J. |last2=Humle |first2=T. |last3=Anderson |first3=J. R. |title=Chimpanzees share forbidden fruit |journal=PLOS ONE |volume=2 |issue=9 |pages=e886 |year=2007 |pmid=17849015 |pmc=1964537 |doi=10.1371/journal.pone.0000886 |editor1-last=Brosnan |editor1-first=S. |display-authors=etal |bibcode=2007PLoSO...2..886H|doi-access=free }}</ref>

====Puzzle solving====
<!--No info available on bonobos?-->
In February 2013, a study found that chimpanzees solve puzzles for entertainment.<ref>{{Cite news |title=Chimps solve puzzles for the thrill of it, researchers find |date=February 24, 2013 |author=Gray, R. |work=Daily Telegraph |url=https://www.telegraph.co.uk/news/science/science-news/9889999/Chimps-solve-puzzles-for-the-thrill-of-it-researchers-find.html |access-date=February 24, 2013}}</ref>

==Chimpanzees in human history==
<!--No info available on bonobos?-->
[[File:2006-12-09 Chimpanzee Gregoire D Bruyere.JPG|thumb|alt=62-year-old chimpanzee|[[Gregoire (chimpanzee)|Gregoire]]: 62-year-old chimpanzee]]
Chimpanzees, as well as other apes, had also been purported to have been known to ancient writers, but mainly as myths and legends on the edge of European and Near Eastern societal consciousness. Apes are mentioned variously by [[Aristotle]]. The English word ''ape'' translates Hebrew ''קוף (qof)'' in [[English translations of the Bible]] ([[1 Kings]] 10:22), but the word may refer to a monkey rather than an ape proper.

The diary of Portuguese explorer [[Duarte Pacheco Pereira]] (1506), preserved in the Portuguese National Archive (''Torre do Tombo''), is probably the first written document to acknowledge that chimpanzees built their own rudimentary tools.{{Citation needed|date=January 2021}} The first of these early transcontinental chimpanzees came from Angola and were presented as a gift to [[Frederick Henry, Prince of Orange]] in 1640, and were followed by a few of its brethren over the next several years. Scientists described these first chimpanzees as "[[pygmies]]", and noted the animals' distinct similarities to humans. The next two decades, a number of the creatures were imported into Europe, mainly acquired by various zoological gardens as entertainment for visitors.

[[File:HugoRheinholdApeWithSkull.DarwinMonkey.2.jpg|thumb|upright|left|[[Hugo Rheinhold]]'s c. 1893 ''[[Affe mit Schädel]]'' ("Ape with skull").]]
[[Charles Darwin]]'s [[theory of natural selection]] (published in 1859) spurred scientific interest in chimpanzees, as in much of [[biology|life science]], leading eventually to numerous studies of the animals in the wild and captivity. The observers of chimpanzees at the time were mainly interested in behaviour as it related to that of humans. This was less strictly and disinterestedly scientific than it might sound, with much attention being focused on whether or not the animals had traits that could be considered 'good'; the intelligence of chimpanzees was often significantly exaggerated, as immortalized in [[Hugo Rheinhold]]'s ''[[Affe mit Schädel]]'' (see image, left). By the end of the 19th century, chimpanzees remained very much a mystery to humans, with very little factual scientific information available.{{fact|date=April 2023}}

In the 20th century, a new age of scientific research into chimpanzee behaviour began<!-- a century can see?-->. Before 1960, almost nothing was known about chimpanzee behaviour in their natural habitats. In July of that year, [[Jane Goodall]] set out to [[Tanzania]]'s [[Gombe Stream National Park|Gombe]] forest to live among the chimpanzees, where she primarily studied the members of the [[Kasakela chimpanzee community]]. Her discovery that chimpanzees made and used tools was groundbreaking, as humans were previously believed to be the only species to do so. The most progressive early studies on chimpanzees were spearheaded primarily by [[Wolfgang Köhler]] and [[Robert Yerkes]], both of whom were renowned psychologists. Both men and their colleagues established laboratory studies of chimpanzees focused specifically on learning about the intellectual abilities of chimpanzees, particularly [[problem-solving]]. This typically involved basic, practical tests on laboratory chimpanzees, which required a fairly high intellectual capacity (such as how to solve the problem of acquiring an out-of-reach banana). Notably, Yerkes also made extensive observations of chimpanzees in the wild which added tremendously to the scientific understanding of chimpanzees and their behaviour. Yerkes studied chimpanzees until [[World War II]], while Köhler concluded five years of study and published his famous ''Mentality of Apes'' in 1925 (which is coincidentally when Yerkes began his analyses), eventually concluding, "chimpanzees manifest intelligent behaviour of the general kind familiar in human beings ... a type of behaviour which counts as specifically human" (1925).<ref name=goodall>{{Cite book |last=Goodall |first=J. |author-link=Jane Goodall |year=1986 |title=The Chimpanzees of Gombe: Patterns of Behavior |isbn=978-0-674-11649-8 |publisher=Belknap Press of Harvard University Press |location=Cambridge, Massachusetts |url=https://archive.org/details/chimpanzeesofgom00good}}</ref>
[[File:Lightmatter chimp.jpg|thumb|right|Chimpanzee at the [[Los Angeles Zoo]]]]

The August 2008 issue of the ''American Journal of Primatology'' reported results of a year-long study of chimpanzees in Tanzania's [[Mahale Mountains National Park]], which produced evidence of chimpanzees becoming sick from viral infectious diseases they had likely contracted from humans. Molecular, microscopic and epidemiological investigations demonstrated the chimpanzees living at Mahale Mountains National Park have been suffering from a respiratory disease that is likely caused by a variant of a human [[Paramyxoviridae|paramyxovirus]].<ref>{{cite news |url=http://newswise.com/articles/view/541407/ |title=Researchers find human virus in chimpanzees |publisher=Newswise |date=June 3, 2008}}</ref>

==Conservation==
<!--No mention of bonobos? -->
{{see also|Animal testing on non-human primates#Chimpanzees in the U.S.}}
The US Fish and Wildlife Service finalized a rule on June 12, 2015, creating very strict regulations, practically barring any activity with chimpanzees other than for scientific, preservation-oriented purposes.<ref>{{cite web |url=http://www.fws.gov/news/ShowNews.cfm?ID=E81DA137-BAF2-9619-3492A2972E9854D9 |title=U.S. Fish and Wildlife Service finalizes rule listing all chimpanzees as Endangered under the Endangered Species Act |publisher=U.S. Fish and Wildlife Service |quote=Certain activities involving chimpanzees will be prohibited without a permit, including import and export of the animals into and out of the United States, "take" (defined by the ESA as harm, harass, kill, injure, etc.) within the United States, and interstate and foreign commerce. Permits will be issued for these activities only for scientific purposes that benefit the species in the wild, or to enhance the propagation or survival of chimpanzees, including habitat restoration and research on chimpanzees in the wild that contributes to improved management and recovery. |access-date=2016-08-30}}</ref>

==See also==
{{div col|colwidth=30em}}
* [[Anthropopithecus]]
* [[Bili ape]]
* [[Chimp Haven]]
* [[Chimpanzee genome project]]
* [[Dian Fossey]]
* [[Great ape personhood]]
* [[Jane Goodall]]
* [[List of apes]]
* [[Monkey Day]]
* [[Prostitution among animals#Chimpanzees]]
* [[The Third Chimpanzee]]
{{div col end}}

==Notes==
{{reflist|group=Note}}

==References==
{{Reflist|refs=
<ref name="IUCNBonobo">{{cite iucn |last1=Fruth |first1=B. |last2=Hickey |first2=J. R. |last3=André |first3=C. |last4=Furuichi |first4=T. |last5=Hart |first5=J. |last6=Hart |first6=T. |last7=Kuehl |first7=H. |last8=Maisels |first8=F. |last9=Nackoney |first9=J. |last10=Reinartz |first10=G. |last11=Sop |first11=T. |last12=Thompson |first12=J. |last13=Williamson |first13=E. A. |title=''Pan paniscus'' |errata=2016 |volume=2016 |page=e.T15932A102331567 |date=2016 |doi=10.2305/IUCN.UK.2016-2.RLTS.T15932A17964305.en}}</ref>
<ref name="AfricanMammals97">[[#CITEREF_AfricanMammals|Kingdon]], p. 97</ref>
<ref name="IUCNChimpanzee">{{cite iucn |last1=Humle |first1=T. |last2=Maisels |first2=F. |last3=Oates |first3=J. F. |last4=Plumptre |first4=A. |last5=Williamson |first5=E. A. |title=''Pan troglodytes'' |errata=2018 |volume=2016 |page=e.T15933A129038584 |date=2016 |doi=10.2305/IUCN.UK.2016-2.RLTS.T15933A17964454.en}}</ref>
<ref name="ADWChimpanzee">{{cite web |first1=Nancy |last1=Shefferly |title=''Pan troglodytes'' |url=https://animaldiversity.org/accounts/Pan_troglodytes/ |date=2005 |website=[[Animal Diversity Web]] |publisher=[[University of Michigan]] |access-date=August 24, 2023 |archive-date=August 30, 2023 |archive-url=https://web.archive.org/web/20230830011902/https://animaldiversity.org/accounts/Pan_troglodytes/ |url-status=live }}</ref>
<ref name="AfricanMammals95">[[#CITEREF_AfricanMammals|Kingdon]], p. 95</ref>
}}

==Sources==
{{refbegin}}
* {{cite book |title=The Kingdon Field Guide to African Mammals |edition=Second |last=Kingdon |first=Jonathan |date=2015 |publisher=[[Bloomsbury Publishing]] |isbn=978-1-4729-2531-2 |ref=CITEREF_AfricanMammals}}
{{refend}}

==Further reading==
* [[John D. Hawks|Hawks, John]]. [http://www.slate.com/id/2212232/ "How Strong Is a Chimpanzee?"]. ''[[Slate (magazine)|Slate]]''. February 25, 2009.
* Pickrell, John. (September 24, 2002). [https://web.archive.org/web/20170907210754/http://news.nationalgeographic.com/news/2002/09/0924_020924_dnachimp.html "Humans, Chimps Not as Closely Related as Thought?"]. ''[[National Geographic]]''. Archived September 7, 2017. 
* [[Carl Zimmer|Zimmer, Carl]]. [https://www.nytimes.com/2018/09/11/science/generosity-apes-bonobos.html "On the Origin of Humans' Generosity"]. ''[[The New York Times]]''. September 11, 2018.

==External links==
{{Wikiquote|Chimpanzees}}
{{Wikispecies|Pan|Chimpanzee}}
* {{wiktionary-inline|chimpanzee}}
* {{Commons-inline|Pan (genus)|''Pan''}}
* {{Cite Americana |last=Ingersoll |first=Ernest |author-link=Ernest Ingersoll |wstitle=Chimpanzee  |short=x}}
* {{Cite EB1911 |last=Lydekker |first=Richard |author-link=Richard Lydekker |wstitle=Chimpanzee  |short=x}}
*Stanford, Craig B. [http://www-rcf.usc.edu/~stanford/chimphunt.html The Predatory Behavior and Ecology of Wild Chimpanzees] {{Webarchive|url=https://web.archive.org/web/20100629151044/http://www-rcf.usc.edu/~stanford/chimphunt.html |date=June 29, 2010 }} university of Southern California. 2002(?)
* [http://www.chimpcare.org/ ChimpCARE.org]
* {{UCSC genomes|panTro4}}
* [http://humanorigins.si.edu/evidence/human-evolution-timeline-interactive Human Timeline (Interactive)] – [[Smithsonian Institution|Smithsonian]], [[National Museum of Natural History]] (August 2016).

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[[Category:Pan (genus)| ]]
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[[Category:Extant Pliocene first appearances]]
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[[Category:Taxa described in 1816]]
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