Editing Gibbon (section)

==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{{citation needed|reason=It does not appear to be unique at all. but perhaps "special" in the sense that it is similar to the human [[wrist]]?|date=May 2024}} 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 [[siamang]] have an enlarged [[throat sac]], which inflates and serves as a [[Resonating chamber (anatomy)|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 [[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>