View source for Biology:Gibbon

{{short description|Family of apes}}
{{About|a family of apes}}{{Automatic taxobox
| name = Gibbons<ref name=MSW3>{{MSW3 Groves|pages=178–181|id=12100752}}</ref><ref name=Mootnick>{{cite journal | last = Mootnick | first = A. |author2=Groves, C. P. | year = 2005 | title = A new generic name for the hoolock gibbon (Hylobatidae) | journal = International Journal of Primatology | issue = 4 | pages = 971–976 | doi = 10.1007/s10764-005-5332-4 | volume = 26| s2cid = 8394136 }}</ref>
| status = CITES_A1
| status_system = CITES
| status_ref = <ref>{{Cite web|title=Appendices {{!}} CITES|url=https://cites.org/eng/app/appendices.php|access-date=2022-01-14|website=cites.org}}</ref>
| fossil_range = {{Fossil range|13.8|0}}<small>Late Miocene–recent</small>
| image = Gibbon_collage.png
| image_upright = 1.2
| image_caption = Gibbon species of different genera; from top-left, clockwise: [[Biology:Pileated gibbon|Pileated gibbon]] (''Hylobates pileatus''), [[Biology:Western hoolock gibbon|western hoolock gibbon]] (''Hoolock hoolock''), [[Biology:Yellow-cheeked gibbon|yellow-cheeked gibbon]] (''Nomascus gabriellae''), [[Biology:Siamang|siamang]] (''Symphalangus syndactylus'')
| display_parents = 2
| taxon = Hylobatidae
| authority = Gray, 1870
| type_genus = ''[[Biology:Hylobates|Hylobates]]''
| type_genus_authority = Illiger, 1811
| subdivision_ranks = Genera
| subdivision = * ''[[Biology:Hylobates|Hylobates]]''
* ''[[Biology:Hoolock|Hoolock]]''
* ''[[Biology:Nomascus|Nomascus]]''
* ''[[Biology:Symphalangus|Symphalangus]]''
* †''[[Biology:Bunopithecus|Bunopithecus]]''
* †''[[Biology:Junzi imperialis|Junzi]]''
* †''[[Biology:Yuanmoupithecus|Yuanmoupithecus]]''<ref name=Ji>{{Cite journal |last1=Ji |first1=Xueping |last2=Harrison |first2=Terry |last3=Zhang |first3=Yingqi |last4=Wu |first4=Yun |last5=Zhang |first5=Chunxia |last6=Hu |first6=Jinming |last7=Wu |first7=Dongdong |last8=Hou |first8=Yemao |last9=Li |first9=Song |last10=Wang |first10=Guofu |last11=Wang |first11=Zhenzhen |date=2022-10-01 |title=The earliest hylobatid from the Late Miocene of China |journal=Journal of Human Evolution |language=en |volume=171 |pages=103251 |doi=10.1016/j.jhevol.2022.103251 |pmid=36113226 |s2cid=252243877 |issn=0047-2484|doi-access=free }}</ref>
| range_map = Distribución hylobatidae.png
| range_map_alt = 
| range_map_caption = Distribution in Southeast Asia
}}
[[File:Gibbon Rehabilitation Project - Phuket - 20131029 - Cris de singes 1.ogg|thumb|Gibbon Rehabilitation Project, 2013]]
'''Gibbons''' ({{IPAc-en|ˈ|ɡ|ɪ|b|ə|n|z}}) are [[Biology:Ape|ape]]s in the family '''Hylobatidae''' ({{IPAc-en|ˌ|h|aɪ|l|ə|ˈ|b|æ|t|ᵻ|d|iː}}). The family historically contained one [[Biology:Genus|genus]], but now is split into four extant genera and 20 [[Biology:Species|species]]. Gibbons live in subtropical and tropical rainforests from eastern Bangladesh to Northeast India to southern China and Indonesia (including the islands of Sumatra, Borneo and Java).

Also called the '''lesser apes''', gibbons differ from great apes ([[Biology:Bonobo|bonobo]]s, [[Biology:Chimpanzee|chimpanzee]]s, [[Biology:Gorilla|gorilla]]s, [[Biology:Orangutan|orangutan]]s and [[Biology:Human|human]]s) in being smaller, exhibiting low [[Biology:Sexual dimorphism|sexual dimorphism]], and not making nests.<ref>{{Cite web|url = http://voices.nationalgeographic.com/2014/03/03/gibbon-conservation-center-working-to-save-south-asias-hoolock-gibbons-other-small-apes/|archive-url = https://web.archive.org/web/20141105120232/http://voices.nationalgeographic.com/2014/03/03/gibbon-conservation-center-working-to-save-south-asias-hoolock-gibbons-other-small-apes/|url-status = dead|archive-date = November 5, 2014|title = Gibbon Conservation Center Working to Save South Asia's Hoolock Gibbons & Other "Small Apes"|access-date = 14 February 2016|website = National Geographic = }}</ref> Like all apes, gibbons are [[Biology:Tail|tail]]less. Unlike most of the great apes, gibbons frequently form long-term [[Philosophy:Pair bond|pair bond]]s. Their primary mode of locomotion, brachiation, involves swinging from branch to branch for distances up to {{cvt|15|m|-1|abbr=on}}, at speeds as fast as {{cvt|55|km/h|abbr=on}}. They can also make leaps up to {{cvt|8|m|abbr=on}}, and walk bipedally with their arms raised for balance. They are the fastest of all tree-dwelling, nonflying mammals.<ref>{{Cite web|url = http://a-z-animals.com/animals/gibbon/|title = Gibbon|access-date = 26 March 2015|website = a-z animals}}</ref>

Depending on the species and sex, gibbons' fur coloration varies from dark- to light-brown shades, and any shade between black and white, though a completely "white" gibbon is rare.

==Etymology==
The English word "gibbon" is a reborrowing from French and may originally derive from an Orang Asli word.<ref>{{cite journal |last1=Lim |first1=Teckwyn |title=An Aslian origin for the word gibbon |journal=Lexis |date=2020 |volume=15 |url=http://journals.openedition.org/lexis/4291}}</ref>

==Evolutionary history==
Whole genome molecular dating analyses indicate that the gibbon lineage diverged from that of great apes around 16.8 million years ago (Mya) (95% confidence interval: 15.9–17.6 Mya; given a divergence of 29 Mya from Old World monkeys).<ref name="Carbone et al. 2014">{{cite journal|last1=Carbone|first1=Lucia|title=Gibbon genome and the fast karyotype evolution of small apes|journal=Nature|date=2014|volume=513|issue=11 September 2014|pages=195–201 |doi= 10.1038/nature13679| display-authors=0|pmid=25209798|pmc=4249732|bibcode=2014Natur.513..195C}}</ref> Adaptive divergence associated with chromosomal rearrangements led to rapid radiation of the four genera 5–7 Mya. Each genus comprises a distinct, well-delineated lineage, but the sequence and timing of divergences among these genera has been hard to resolve, even with whole genome data, due to radiative speciations and extensive [[Biology:Incomplete lineage sorting|incomplete lineage sorting]].<ref name="Carbone et al. 2014"/><ref name="Matsudaira2010">{{cite journal| last1= Matsudaira |first1=K| last2= Ishida |first2= T |date= May 2010| title= Phylogenetic relationships and divergence dates of the whole mitochondrial genome sequences among three gibbon genera| journal= Mol. Phylogenet. Evol.| volume= 55| number= 2| pages= 454–59| doi= 10.1016/j.ympev.2010.01.032| pmid= 20138221 | access-date= }}</ref> An analysis based on [[Biology:Morphology|morphology]] suggests that the four genera are ordered as (''Symphalangus'', (''Nomascus'', (''Hoolock'', ''Hylobates''))).<ref>{{cite journal| first1= Thomas |last1=Geissmann |doi= 10.1002/evan.10047|title=Taxonomy and evolution of gibbons| journal=Evolutionary Anthropology: Issues, News, and Reviews |volume= 11|pages=28–31|year=2003|citeseerx=10.1.1.524.4224|s2cid=36655075}}</ref>

{{clade
       |1={{clade|label1=[[Biology:Hylobatidae|Hylobatidae]] |1={{clade
         |label1=(gibbons)
           |1={{clade
           |1=''[[Biology:Symphalangus|Symphalangus]]''
           |label2=
           |2={{clade
             |1=''[[Biology:Nomascus|Nomascus]]''
             |2={{clade
             |1=''[[Biology:Hoolock|Hoolock]]''
             |2=''[[Biology:Hylobates|Hylobates]]''
             }}
           }} }}}}
       |label2=[[Biology:Hominidae|Hominidae]] (hominids, great apes)
       |2={{clade|label1=[[Biology:Ponginae|Ponginae]] |1={{clade
         |label1= (orangutans)           |1={{clade
           }} }}
         |label2=[[Biology:Homininae|Homininae]]
          |2={{clade|label1=[[Biology:Gorillini|Gorillini]] |1={{clade
             |label1=(gorillas)
             |1={{clade
             }} }}
             |label2=[[Biology:Hominini|Hominini]]
             |2={{clade
                |label1=[[Biology:Panina|Panina]]
                |1={{clade|label1=(chimpanzees)|1={{clade
                }} }}
                |2={{clade|label1=[[Biology:Hominina|Hominina]] (humans)|1={{clade
                }} }}
             }}          
         }}
      }}                
   }}|style1=font-size:90%|label1=[[Biology:Hominoidea|Hominoidea]] (hominoids, apes) }}

A [[Biology:Multispecies coalescent process|coalescent-based]] species tree analysis of genome-scale datasets suggests a phylogeny for the four genera ordered as (''Hylobates'', (''Nomascus'', (''Hoolock'', ''Symphalangus''))).<ref>{{cite journal| last1= Shi| first1=Cheng-Min|last2=Yang|first2=Ziheng|title=Coalescent-Based Analyses of Genomic Sequence Data Provide a Robust Resolution of Phylogenetic Relationships among Major Groups of Gibbons|journal=Molecular Biology and Evolution|date=January 2018| volume=35|issue=1|pages=159–179|doi=10.1093/molbev/msx277|pmid=29087487|pmc=5850733}}</ref>

{{clade
       |1={{clade|label1=[[Biology:Hylobatidae|Hylobatidae]] |1={{clade
         |label1=(gibbons)
           |1={{clade
           |1=''[[Biology:Hylobates|Hylobates]]''
           |label2=
           |2={{clade
             |1=''[[Biology:Nomascus|Nomascus]]''
             |2={{clade
             |1=''[[Biology:Hoolock|Hoolock]]''
             |2=''[[Biology:Symphalangus|Symphalangus]]''
             }}
           }} }}}}
       |label2=[[Biology:Hominidae|Hominidae]] (hominids, great apes)
       |2={{clade|label1=[[Biology:Ponginae|Ponginae]] |1={{clade
         |label1= (Orangutans)           |1={{clade
           }} }}
         |label2=[[Biology:Homininae|Homininae]]
          |2={{clade|label1=[[Biology:Gorillini|Gorillini]]  |1={{clade
             |label1=(Gorilla)
             |1={{clade
             }} }}
             |label2=[[Biology:Hominini|Hominini]]
             |2={{clade
                |label1=[[Biology:Panina|Panina]]
                |1={{clade|label1=(chimpanzees)|1={{clade
                }} }}
                |2={{clade|label1=[[Biology:Hominina|Hominina]] (Humans)|1={{clade
                }} }}
             }}          
         }}
      }}                
   }}|style1=font-size:90%|label1=[[Biology:Hominoidea|Hominoidea]] (hominoids, apes) }}

At the species level, estimates from mitochondrial DNA genome analyses suggest that ''Hylobates pileatus'' diverged from ''H. lar'' and ''H. agilis'' around 3.9 Mya, and ''H. lar'' and ''H. agilis'' separated around 3.3 Mya.<ref name="Matsudaira2010"/> Whole genome analysis suggests divergence of ''H. pileatus'' from ''H. moloch'' 1.5–3.0 Mya.<ref name="Carbone et al. 2014"/> The extinct ''[[Biology:Bunopithecus|Bunopithecus sericus]]'' is a gibbon or gibbon-like ape, which until recently, was thought to be closely related to the hoolock gibbons.<ref name=Mootnick/>

==Taxonomy==
{{main|Biology:List of hominoids}}

[[File:Hominoid taxonomy 7.svg|thumb|220px|Hominoid family tree]]
[[File:Witwanggibbon M.jpg|thumb|Northern white-cheeked gibbon, ''Nomascus leucogenys'']]

The family is divided into four [[Biology:Genus|genera]] based on their diploid [[Biology:Chromosome|chromosome]] number: ''[[Biology:Hylobates|Hylobates]]'' (44), ''[[Biology:Hoolock|Hoolock]]'' (38), ''[[Biology:Nomascus|Nomascus]]'' (52), and ''[[Biology:Symphalangus|Symphalangus]]'' (50).<ref name="Mootnick"/><ref name=Geissmann>{{cite journal | last = Geissmann | first = Thomas | journal = International Zoo News | title = Gibbon systematics and species identification | volume = 42 | url = http://gibbons.de/main/papers/pdf_files/1995gibbon_systematics_big.pdf | date=December 1995 | access-date = 2008-08-15 | pages = 467–501}}</ref> Also, three extinct genera currently are recognised: ''[[Biology:Bunopithecus|Bunopithecus]]'', ''[[Biology:Junzi imperialis|Junzi]]'', and ''[[Biology:Yuanmoupithecus|Yuanmoupithecus]]''.<ref name="Mootnick"/><ref>{{Cite news |last1=Weintraub |first1=Karen |title= Extinct gibbon found in tomb of ancient Chinese emperor's grandmother |journal=The New York Times |url= https://www.nytimes.com/2018/06/21/science/extinct-gibbon-china.html |language=en|date=2018-06-21 |access-date= 2021-01-13}}</ref><ref name="SN-20200908">{{cite news |last=Bower |first=Bruce |title=A stray molar is the oldest known fossil from an ancient gibbon - Ancestors of these small-bodied apes were in India roughly 13 million years ago, a study suggests |url=https://www.sciencenews.org/article/ancient-primates-apes-gibbon-tooth |date=8 September 2020 |work=Science News |access-date=8 September 2020 }}</ref><ref name=Ji/><ref>{{Cite book|last=Sonstige|first=Wilson, Don E. 1944- Hrsg. Cavallini, Paolo|url=http://worldcat.org/oclc/1222638259|title=Handbook of the mammals of the world|date=2013|publisher=Lynx Edicions|isbn=978-84-96553-89-7|oclc=1222638259}}</ref>

'''Family Hylobatidae''': gibbons<ref name="MSW3"/><ref name=Geissmann/><ref name=gibbons-de>{{cite web| last= Geissmann| first= Thomas| url= http://gibbons.de/main/system/system.html#framework | work= Gibbon Systematics and Species Identification| title= Chapter 3: "Adopting a Systematic Framework| access-date= 2011-04-05| via= gibbons.de}}</ref>
* Genus ''[[Biology:Hoolock|Hoolock]]''
** [[Biology:Western hoolock gibbon|Western hoolock gibbon]], ''H. hoolock''
** [[Biology:Eastern hoolock gibbon|Eastern hoolock gibbon]], ''H. leuconedys''
** [[Biology:Skywalker hoolock gibbon|Skywalker hoolock gibbon]], ''H. tianxing''<ref>{{cite news |url= https://www.theguardian.com/environment/2017/jan/11/new-species-of-gibbon-discovered-in-china |title=New species of gibbon discovered in China |first=Georgia |last=Brown|date= 11 January 2017|work=The Guardian | access-date= January 13, 2021}}</ref>
* Genus ''[[Biology:Hylobates|Hylobates]]'': dwarf gibbons
** [[Biology:Lar gibbon|Lar gibbon]] or white-handed gibbon, ''H. lar''
** [[Biology:Bornean white-bearded gibbon|Bornean white-bearded gibbon]], ''H. albibarbis''
** [[Biology:Agile gibbon|Agile gibbon]] or black-handed gibbon, ''H. agilis''
**[[Biology:Western grey gibbon|Western grey gibbon]] or Abbott's grey gibbon, ''H. abbotti<ref name=":0">{{Cite book|last=Sonstige|first=Wilson, Don E. 1944- Hrsg. Cavallini, Paolo|url=http://worldcat.org/oclc/1222638259|title=Handbook of the mammals of the world|date=2013|publisher=Lynx Edicions|isbn=978-84-96553-89-7|oclc=1222638259}}</ref>''
**[[Biology:Eastern grey gibbon|Eastern grey gibbon]] or northern grey gibbon, ''H. funereus<ref name=":0" />''
** [[Biology:Müller's gibbon|Müller's gibbon]] or southern grey gibbon, ''H. muelleri''
** [[Biology:Silvery gibbon|Silvery gibbon]], ''H. moloch''
** [[Biology:Pileated gibbon|Pileated gibbon]] or capped gibbon, ''H. pileatus''
** [[Biology:Kloss's gibbon|Kloss's gibbon]], Mentawai gibbon or bilou, ''H. klossii''
* Genus ''[[Biology:Symphalangus|Symphalangus]]''
** [[Biology:Siamang|Siamang]], ''S. syndactylus''
* Genus ''[[Biology:Nomascus|Nomascus]]'': crested gibbons
** [[Biology:Northern buffed-cheeked gibbon|Northern buffed-cheeked gibbon]], ''N. annamensis''
** Concolor or [[Biology:Black crested gibbon|black crested gibbon]], ''N. concolor''
** [[Biology:Eastern black crested gibbon|Eastern black crested gibbon]] or Cao Vit black crested gibbon, ''N. nasutus''
** [[Biology:Hainan black crested gibbon|Hainan black crested gibbon]], ''N. hainanus''
** [[Biology:Northern white-cheeked gibbon|Northern white-cheeked gibbon]], ''N. leucogenys''
** [[Biology:Southern white-cheeked gibbon|Southern white-cheeked gibbon]], ''N. siki''
** [[Biology:Yellow-cheeked gibbon|Yellow-cheeked gibbon]], ''N. gabriellae''

=== Extinct genera ===
* Genus ''[[Biology:Bunopithecus|Bunopithecus]]''
** ''Bunopithecus sericus''
* Genus ''Junzi''
** ''[[Biology:Junzi imperialis|Junzi imperialis]]''
*Genus ''[[Biology:Yuanmoupithecus|Yuanmoupithecus]]''<ref name=Ji/>
** ''[[Biology:Yuanmoupithecus xiaoyuan|Yuanmoupithecus xiaoyuan]]''

===Hybrids===
Many gibbons are hard to identify based on fur coloration, so are identified either by song or genetics.<ref name=songs>{{cite journal |title=Songs of hybrid gibbons (''Hylobates lar'' × ''H. muelleri'') |author=Tenaza, R. |year=1984 |journal=American Journal of Primatology |volume=8 |issue=3 |pages=249–253 |doi=10.1002/ajp.1350080307 |pmid=31986810|s2cid=84957700 }}</ref> These morphological ambiguities have led to hybrids in zoos. Zoos often receive gibbons of unknown origin, so they rely on morphological variation or labels that are impossible to verify to assign species and subspecies names, so separate species of gibbons commonly are misidentified and housed together. Interspecific hybrids, within a genus, are also suspected to occur in wild gibbons where their ranges overlap.<ref>{{cite journal |author=Sugawara, K. |title=Sociological study of a wild group of hybrid baboons between ''Papio anubis'' and ''P. hamadryas'' in the Awash Valley, Ethiopia |year=1979 |journal=Primates |volume=20 |issue=1 |doi=10.1007/BF02373827 |pages=21–56|s2cid=23061688 }}</ref> No records exist, however, of fertile hybrids between different gibbon genera, either in the wild or in captivity.<ref name="Carbone et al. 2014"/>

==Description==
[[File:Gibbon Arm vs. Human Arm.svg|thumb|upright|Gibbon arm skeleton (left) compared to average human male arm bone structure (right): Scapula (red), humerus (orange), ulna (yellow), and radius (blue) are shown in both structures.]]
One unique aspect of a gibbon's anatomy is the wrist, which functions something like a ball-and-socket joint, allowing for biaxial movement. This greatly reduces the amount of energy needed in the upper arm and torso, while also reducing stress on the shoulder joint. Gibbons also have long hands and feet, with a deep cleft between the first and second digits of their hands. Their fur is usually black, gray, or brownish, often with white markings on hands, feet and face. Some species such as the [[Biology:Siamang|siamang]] have an enlarged throat sac, which inflates and serves as a resonating chamber when the animals call. This structure can become quite large in some species, sometimes equaling the size of the animal's head. Their voices are much more powerful than that of any human singer, although they are at best half a human's height.<ref>{{cite book|title=Organic Evolution|year=1921|publisher=The Macmillan Company|location=New York|pages=641–677|first=Richard Swann |last= Lull| chapter= Seventy Seven}}</ref>

Gibbon skulls and teeth resemble those of the great apes, and their noses are similar to those of all catarrhine primates. The [[Biology:Dentition#Dental formula|dental formula]] is {{DentalFormula|upper=2.1.2.3|lower=2.1.2.3}}.<ref name=ADW>Myers, P. 2000. [http://animaldiversity.ummz.umich.edu/site/accounts/information/Hylobatidae.html Family Hylobatidae], Animal Diversity Web. Accessed April 05, 2011-04-05.</ref> The siamang, which is the largest of the 18 species, is distinguished by having two fingers on each foot stuck together, hence the generic and species names ''Symphalangus'' and ''syndactylus''.<ref>{{cite web| url= http://gibbons.de/main/index.html| last= Geissmann |first= T. |title= Typical Characteristics |work=Gibbon Research Lab |year=2011 |access-date=17 August 2011}}</ref>

==Behavior==
[[File:Agilegibbon.jpg|thumb|left|Agile gibbon, ''Hylobates agilis'']]

Like all primates, gibbons are social animals. They are strongly territorial, and defend their boundaries with vigorous visual and vocal displays. The vocal element, which can often be heard for distances up to {{Cvt|1|km|abbr=on}}, consists of a duet between a mated pair, with their young sometimes joining in. In most species, males and some females sing solos to attract mates, as well as advertise their territories.<ref>{{cite journal |vauthors=Clarke E, Reichard UH, Zuberbühler K |title=The Syntax and Meaning of Wild Gibbon Songs |journal=PLOS ONE |volume=1 |issue= 1|pages=e73 |year=2006 |pmid=17183705 |pmc=1762393 |doi=10.1371/journal.pone.0000073 |editor1-last=Emery |editor1-first=Nathan|bibcode=2006PLoSO...1...73C |doi-access=free }}</ref> The song can be used to identify not only which species of gibbon is singing, but also the area from which it comes.<ref>Glover, Hilary. [http://www.eurekalert.org/pub_releases/2011-02/bc-rgf020411.php Recognizing gibbons from their regional accents], BioMed Central, EurekAlert.org, 6 February 2011.</ref>

Gibbons often retain the same mate for life, although they do not always remain sexually monogamous. In addition to [[Biology:Extra-pair copulation|extra-pair copulation]]s, pair-bonded gibbons occasionally "divorce".<ref>{{cite journal | last1 = Reichard | first1 = U | year = 1995 | title = Extra-pair copulations in a monogamous gibbon (Hylobates lar) | doi =10.1111/j.1439-0310.1995.tb00319.x | journal = Ethology | volume = 100 | issue = 2| pages = 99–112 }}</ref><ref>{{Cite book|title = The Encyclopedia of World Wildlife|last1 = Briggs|first1 = Mike|publisher = Parragon|year = 2005|isbn = 978-1405456807|pages = 146|first2 = Peggy|last2 = Briggs}}</ref>

Gibbons are among nature's best brachiators. Their ball-and-socket wrist joints allow them unmatched speed and accuracy when swinging through trees. Nonetheless, their mode of transportation can lead to hazards when a branch breaks or a hand slips, and researchers estimate that the majority of gibbons suffer bone fractures one or more times during their lifetimes.<ref name=LOM/> They are the fastest of all tree-dwelling, nonflying mammals.<ref name=LOM>[[Biography:David Attenborough|Attenborough, David]]. ''Life of Mammals'', "Episode 8: Life in the Trees", BBC Warner, 2003.</ref> On the ground, gibbons tend to walk bipedally, and their [[Medicine:Achilles tendon|Achilles tendon]] morphology is more similar to that of humans than that of any other ape.<ref>{{cite journal|last1=Aerts|first1=P.|last2=d'Août|first2=K.|last3=Thorpe|first3=S.|last4=Berillon|first4=G.|last5=Vereecke|first5=E.|year=2018|title=The gibbon's Achilles tendon revisited: consequences for the evolution of the great apes?|journal=Proceedings of the Royal Society B|volume=285|issue=1880|pages=20180859|doi=10.1098/rspb.2018.0859|pmid=29899076 |pmc=6015853 }}</ref>

==Diet==
Gibbons' diets are about 60% fruit-based,<ref name="monkeyworld">[http://www.monkeyworlds.com/gibbon/ Gibbon - Monkey Worlds] Retrieved Feb-12-2015</ref> but they also consume twigs, leaves, insects, flowers, and occasionally birds' eggs.

== Genetics ==
[[File: Pileated Gibbon (Hylobates pileatus) - Female.jpg|thumb|upright|Pileated gibbon (''Hylobates pileatus'')]]
Gibbons were the first apes to diverge from the common ancestor of humans and apes about 16.8 Mya. With a [[Biology:Genome|genome]] that has a 96% similarity to humans, the gibbon has a role as a bridge between Old World monkeys, such as [[Biology:Macaque|macaque]]s, and the great apes. According to a study that mapped [[Biology:Synteny|synteny]] (genes occurring on the same chromosome) disruptions in the gibbon and human genome, humans and great apes are part of the same superfamily ([[Biology:Hominoidea|Hominoidea]]) with gibbons. The [[Biology:Karyotype|karyotype]] of gibbons, however, diverged in a much more rapid fashion from the common hominoid ancestor than other apes.

The common ancestor of hominoids is shown to have a minimum of 24 major [[Biology:Chromosomal rearrangement|chromosomal rearrangement]]s from the presumed gibbon ancestor's karyotype. Reaching the common gibbon ancestor's karyotype from today's various living species of gibbons will require up to 28 additional rearrangements. Adding up, this implies that at least 52 major chromosomal rearrangements are needed to compare the common hominoid ancestor to today's gibbons. No common specific sequence element in the independent rearrangements was found, while 46% of the gibbon-human synteny breakpoints occur in [[Biology:Segmental duplication|segmental duplication]] regions. This is an indication that these major differences in humans and gibbons could have had a common source of plasticity or change. Researchers view this unusually high rate of chromosomal rearrangement that is specific in small apes such as gibbons could potentially be due to factors that increase the rate of chromosomal breakage or factors that allow derivative chromosomes to be fixed in a homozygous state while mostly lost in other mammals.<ref>{{cite journal | last1 = Carbone | first1 = L. | last2 = Vessere | first2 = G. M. | last3 = ten Hallers | first3 = B. F. H. | last4 = Zhu | first4 = B. | last5 = Osoegawa | first5 = K. | last6 = Mootnick | first6 = A. | last7 = Kofler | first7 = A. | last8 = Wienberg | first8 = J. | last9 = Rogers | first9 = J. | last10 = Humphray | first10 = S. | last11 = Scott | first11 = C. | last12 = Harris | first12 = R. A. | last13 = Milosavljevic | first13 = A. | last14 = de Jong | first14 = P. J. | year = 2006 | title = A high-resolution map of synteny disruptions in gibbon and human genomes | journal = PLOS Genetics | volume = 2 | issue = 12| page = e223 | doi = 10.1371/journal.pgen.0020223 | pmid = 17196042 | pmc = 1756914 | doi-access = free }}</ref>

[[File:Ulluk-2.jpg|thumb|left|Genus ''[[Biology:Hoolock gibbon|Hoolock]]'']]

The whole genome of the gibbons in Southeast Asia was first sequenced in 2014 by the German Primate Center, including Christian Roos, Markus Brameier, and Lutz Walter, along with other international researchers. One of the gibbons that had its genome sequenced is a white-cheeked gibbon (''Nomascus leucogenys'', NLE) named Asia. The team found that a jumping DNA element named LAVA transposon (also called gibbon-specific retrotransposon) is unique to the gibbon genome apart from humans and the great apes. The LAVA transposon increases mutation rate, thus is supposed to have contributed to the rapid and greater change in gibbons in comparison to their close relatives, which is critical for evolutionary development. The very high rate of chromosomal disorder and rearrangements (such as duplications, deletions or inversions of large stretches of DNA) due to the moving of this large DNA segment is one of the key features that are unique to the gibbon genome.

A special feature of the LAVA transposon is that it positioned itself precisely between genes that are involved in [[Biology:Chromosome segregation|chromosome segregation]] and distribution during cell division, which results in a premature termination state leading to an alteration in [[Biology:Transcription|transcription]]. This incorporation of the jumping gene near genes involved in chromosome replication is thought to make the rearrangement in the genome even more likely, leading to a greater diversity within the gibbon genera.<ref name=carbone>{{cite journal | last1 = Carbone | first1 = L. | last2 = Alan Harris | first2 = R. | last3 = Gnerre | first3 = S. | last4 = Veeramah | first4 = K. R. | last5 = Lorente-Galdos | first5 = B. | last6 = Huddleston | first6 = J. | last7 = Meyer | first7 = T. J. | last8 = Herrero | first8 = J. | last9 = Roos | first9 = C. | last10 = Aken | first10 = B. | last11 = Anaclerio | first11 = F. | last12 = Archidiacono | first12 = N. | last13 = Baker | first13 = C. | last14 = Barrell | first14 = D. | last15 = Batzer | first15 = M. A. | last16 = Beal | first16 = K. | last17 = Blancher | first17 = A. | last18 = Bohrson | first18 = C. L. | last19 = Brameier | first19 = M. | last20 = Gibbs | first20 = R. A. | year = 2014 | title = Gibbon genome and the fast karyotype evolution of small apes | journal = Nature | volume = 513 | issue = 7517| pages = 195–201 | doi = 10.1038/nature13679 | pmid = 25209798 | pmc = 4249732 | bibcode = 2014Natur.513..195C }}</ref>

In addition, some characteristic genes in the gibbon genome had gone through a positive selection and are suggested to give rise to specific anatomical features for gibbons to adapt to their new environment. One of them is [[Biology:TBX5 (gene)|''TBX5'']], which is a gene that is required for the development of the front extremities or forelimbs such as long arms. The other is [[Biology:Collagen, type I, alpha 1|''COL1A1'']], which is responsible for the development of [[Biology:Collagen|collagen]], a protein that is directly involved with the forming of connective tissues, bone, and cartilage.<ref name=carbone/> This gene is thought to have a role in gibbons' stronger muscles.<ref>{{cite journal | last1 = Michilsens | first1 = F. | last2 = Vereecke | first2 = E. E. | last3 = D'Août | first3 = K. | last4 = Aerts | first4 = P. | year = 2009 | title = Functional anatomy of the gibbon forelimb: Adaptations to a brachiating lifestyle | journal = Journal of Anatomy | volume = 215 | issue = 3| pages = 335–354 | doi = 10.1111/j.1469-7580.2009.01109.x | pmid = 19519640 | pmc = 2750765 }}</ref>

[[File:Suneko - shout (by).jpg|thumb|Siamang, ''Symphalangus syndactylus'']]

Researchers have found a coincidence between major environmental changes in Southeast Asia about 5 Mya that caused a cyclical dynamic of expansions and contractions of their forest habitat, an instance of radiation experienced by the gibbon genera. This may have led to the development of a suite of physical characteristics, distinct from their great ape relatives, to adapt to their habitat of dense, canopy forest.<ref name=carbone/>

These crucial findings in genetics have contributed to the use of gibbons as a genetic model for chromosome breakage and fusion, which is a type of translocation mutation. The unusually high number of structural changes in the DNA and chromosomal rearrangements could lead to problematic consequences in some species.<ref>{{Cite news |date=2014-09-10 |title=Planet of the apes: Gibbons are last ape to have genome revealed |language=en |work=Reuters |url=https://www.reuters.com/article/us-science-gibbons-idUSKBN0H520320140910 |access-date=2023-05-09}}</ref> Gibbons, however, not only seemed to be free from problems but let the change help them effectively adapt to their environment. Thus, gibbons are organisms on which genetics research could be focused to broaden the implications to human diseases related to chromosomal changes, such as cancer, including chronic myeloid leukemia.<ref>Baylor College of Medicine. (2014, September 10). Gibbon genome sequence deepens understanding of primates rapid chromosomal rearrangements. ScienceDaily. Retrieved April 7, 2020 from www.sciencedaily.com/releases/2014/09/140910132518.htm</ref><ref>{{cite journal | last1 = Weise | first1 = A. | last2 = Kosyakova | first2 = N. | last3 = Voigt | first3 = M. | last4 = Aust | first4 = N. | last5 = Mrasek | first5 = K. | last6 = Löhmer | first6 = S. | last7 = Rubtsov | first7 = N. | last8 = Karamysheva | first8 = T. V. | last9 = Trifonov | first9 = V. A. | last10 = Hardekopf | first10 = D. | last11 = Jančušková | first11 = T. | last12 = Pekova | first12 = S. | last13 = Wilhelm | first13 = K. | last14 = Liehr | first14 = T. | last15 = Fan | first15 = X. | year = 2015 | title = Comprehensive analyses of white-handed gibbon chromosomes enables access to 92 evolutionary conserved breakpoints compared to the human genome | journal = Cytogenetic and Genome Research | volume = 145 | issue = 1| pages = 42–49 | doi = 10.1159/000381764 | pmid = 25926034 | doi-access = free }}</ref>

==Conservation status==
Most species are either [[Biology:Endangered species|endangered]] or [[Biology:Critically endangered|critically endangered]] (the sole exception being ''[[Biology:Eastern hoolock gibbon|H. leuconedys]]'', which is [[Biology:Vulnerable species|vulnerable]]), primarily due to degradation or loss of their forest habitats.<ref name="AZGibbon">[http://a-z-animals.com/animals/gibbon/ A-Z Animals: Gibbon] Retrieved Feb-12-2015</ref> On the island of Phuket in Thailand, a volunteer-based Gibbon Rehabilitation Center rescues gibbons that were kept in captivity, and are being released back into the wild.<ref>{{cite web | url=http://www.gibbonproject.org/ | title=The Gibbon Rehabilitation Project}}</ref> The [[Biology:Kalaweit Project|Kalaweit Project]] also has gibbon rehabilitation centers on Borneo and Sumatra.<ref>{{Cite web |title=Projets |url=https://kalaweit.org/presentation/projets/ |access-date=2023-05-09 |website=Kalaweit |language=fr-FR}}</ref>

The IUCN Species Survival Commission Primate Specialist Group announced 2015 to be the Year of the Gibbon<ref name=YOTG>{{cite web|last1=Mittermeier|first1=Russell|title=Letter of Endorsement - Year of the Gibbon|url=http://www.gibbons.asia/wp-content/uploads/2015/06/Letter-of-Endorsement_YOTG_new.pdf|website=IUCN SSC PSG Section on Small Apes|publisher=IUCN SSC Primate Specialist Group|access-date=30 July 2015|archive-url=https://web.archive.org/web/20160304083038/http://www.gibbons.asia/wp-content/uploads/2015/06/Letter-of-Endorsement_YOTG_new.pdf|archive-date=4 March 2016|url-status=dead}}</ref> and initiated events to be held around the world in zoos to promote awareness of the status of gibbons.<ref name=YOTGevents>{{cite web|title=Year of the Gibbon - Events|url=http://www.gibbons.asia/year-of-the-gibbon/|website=IUCN SSC PSG Section on Small Apes|access-date=30 July 2015|archive-url=https://web.archive.org/web/20150829010643/http://www.gibbons.asia/year-of-the-gibbon/|archive-date=29 August 2015|url-status=dead}}</ref>

==In traditional Chinese culture==
[[File:Yi-Yuanji-Two-gibbons-in-an-oak-tree.jpg|thumb|upright|''Two gibbons in an oak tree'' by the Song dynasty painter Yì Yuánjí]]
{{Further|Biology:Monkeys in Chinese culture}}
Sinologist Robert van Gulik concluded gibbons were widespread in central and southern China until at least the Song dynasty, and furthermore, based on an analysis of references to primates in Chinese poetry and other literature and their portrayal in Chinese paintings, the Chinese word ''yuán'' (猿) referred specifically to gibbons until they were extirpated throughout most of the country due to [[Earth:Habitat destruction|habitat destruction]] (around the 14th century). In modern usage, however, ''yuán'' is a generic word for ape. Early Chinese writers viewed the "noble" gibbons, gracefully moving high in the treetops, as the "gentlemen" (''jūnzǐ'', 君子) of the forest, in contrast to the greedy [[Biology:Macaque|macaque]]s, attracted by human food. The Taoists ascribed occult properties to gibbons, believing them to be able to live for several hundred years and to turn into humans.<ref>van Gulik, Robert. "The gibbon in China. An essay in Chinese animal lore." E. J. Brill, Leiden, Holland. (1967). [http://www.gibbons.de/main/introduction/chapter_english08.html Brief summary]</ref>

Gibbon figurines as old as from the fourth to third centuries BCE (the Zhou dynasty) have been found in China. Later on, gibbons became a popular subject for Chinese painters, especially during the Song dynasty and early Yuan dynasty, when Yì Yuánjí and Mùqī Fǎcháng excelled in painting these apes. From Chinese cultural influence, the [[Philosophy:Zen|Zen]] motif of the "gibbon grasping at the reflection of the moon in the water" became popular in Japanese art, as well, though gibbons have never occurred naturally in Japan.<ref>Geissmann, Thomas. [http://www.gibbonconservation.org//07_journal/gibbon_journal_4.pdf "Gibbon paintings in China, Japan, and Korea: Historical distribution, production rate and context"] {{webarchive|url=https://web.archive.org/web/20081217022947/http://www.gibbonconservation.org//07_journal/gibbon_journal_4.pdf |date=2008-12-17 }}, ''Gibbon Journal'', No. 4, May 2008. (includes color reproductions of a large number of gibbon paintings by many artists)</ref>

==References==
{{Reflist|2}}

==External links==
* [http://gibbons.asia/ IUCN SSC PSG Section on Small Apes]
* [http://www.gibboncenter.org Gibbon Conservation Center]
* [http://www.gibbons.de Gibbon Network and Research Lab]
* [http://www.gibbonconservation.org Gibbon Conservation Alliance]
* [http://www.gibbonproject.org Gibbon Rehabilitation Project]
* {{UCSC genomes|nomLeu3}}

{{Apes}}
{{Taxonbar|from=Q185939}}

[[Category:Gibbons| ]]
[[Category:Primate families]]

{{Sourceattribution|Gibbon}}