Editing Spider monkey (section)

==Anatomy and physiology==
[[File:Spider monkey -Belize Zoo-8b.jpg|thumb|[[Geoffroy's spider monkey]]]]
[[File:Spider Monkey Skeleton.jpg|thumb|Spider monkey [[skeleton]] on display at [[The Museum of Osteology]], [[Oklahoma City, Oklahoma]]]]
Spider monkeys are among the largest New World monkeys; [[black-headed spider monkey]]s, the largest spider monkey, have an average weight of {{convert|11|kg}} for males and {{convert|9.66|kg|lb|abbr=on}} for females.<ref>{{cite journal |author=Youlatos, D. |year=2002 |title=Positional behavior of black spider monkeys (''Ateles paniscus'') in French Guiana |journal=[[International Journal of Primatology]] |volume=23 |issue=5 |pages=1071–93 |doi=10.1023/A:1019602116805 |s2cid=28478677}}</ref><ref>{{cite book |author1=Di Fiore, A.  |author2=Campbell, C.J. |name-list-style=amp |year=2007 |chapter=The atelines: variation in ecology, behavior, and social organization |title=Primates in Perspective |editor=Campbell, C.J. |editor2=Fuentes, A. |editor3=MacKinnon, K.C. |editor4=Panger, M. |editor5=Bearder, S.K. |location=New York |publisher=[[Oxford University Press]] |pages=155–85}}</ref> Disproportionately long, spindly limbs inspired the spider monkey's [[common name]]. Their deftly [[prehensile tail]]s,<ref>{{cite book |author=Benson, Elizabeth P. |title=Birds and Beasts of Ancient Latin America |page=60 |isbn=9780813015187 |year=1997|publisher=University Press of Florida }}</ref> which may be up to {{convert|89|cm|in|abbr=on}} long, have very flexible, hairless tips and skin grooves similar to [[fingerprint]]s. This adaptation to their strictly [[arboreal]] lifestyle serves as a fifth hand.<ref>{{Cite web |title=Swing through the trees With amazing spider monkeys |url=http://video.nationalgeographic.com/video/news/150512-spider-monkeys-prehensile-tails-vin?sf9136397=1 |archive-url=https://web.archive.org/web/20171005050620/http://video.nationalgeographic.com/video/news/150512%2Dspider%2Dmonkeys%2Dprehensile%2Dtails%2Dvin?sf9136397%3D1 |url-status=dead |archive-date=October 5, 2017 |website=video.nationalgeographic.com |access-date=May 13, 2015}}</ref> When the monkey walks, its arms practically drag on the ground. Unlike many monkeys, they do not use their arms for balance when walking, instead relying on their tails. The hands are long, narrow, and hook-like and have reduced or nonexistent thumbs.<ref>{{cite web |title=Spider monkeys |url=http://www.nationalgeographic.com/animals/mammals/group/spider-monkeys/ |archive-url=https://web.archive.org/web/20170222212651/http://www.nationalgeographic.com/animals/mammals/group/spider-monkeys/ |url-status=dead |archive-date=February 22, 2017 |website=[[National Geographic (magazine) |National Geographic]] |date=10 September 2010 |access-date=June 20, 2017}}</ref> The fingers are elongated and recurved.<ref>{{cite web |url=http://www.animalcorner.co.uk/rainforests/spidermonkey.html |title=Rainforest spider monkey |publisher=Animal Corner |date=November 11, 2013 |access-date=November 12, 2013 |archive-date=July 26, 2013 |archive-url=https://web.archive.org/web/20130726050137/http://www.animalcorner.co.uk/rainforests/spidermonkey.html |url-status=live }}</ref>

Their hair is coarse, ranging in color from ruddy gold to brown and black, or white in a rare number of specimens.<ref>{{cite web |url=http://news.nationalgeographic.com/2015/04/150417-ghost-monkey-albino-bear-elephant-animals-science |archive-url=https://web.archive.org/web/20150418035656/http://news.nationalgeographic.com/2015/04/150417-ghost-monkey-albino-bear-elephant-animals-science/ |url-status=dead |archive-date=April 18, 2015 |date=April 17, 2015 |title=Watch incredibly rare white monkeys ghost through a forest |publisher=National Geographic}}</ref><ref>{{Cite web |title=Exclusive: rare ghost monkeys filmed in Colombia |url=http://video.nationalgeographic.com/video/news/150417-ghost-monkeys-colombia-vin |archive-url=https://web.archive.org/web/20150423054035/http://video.nationalgeographic.com/video/news/150417-ghost-monkeys-colombia-vin |url-status=dead |archive-date=April 23, 2015 |website=video.nationalgeographic.com |access-date=May 20, 2015}}</ref> The hands and feet are usually black. Heads are small with hairless faces. The [[nostril]]s are very far apart, which is a distinguishing feature of spider monkeys.<ref>{{cite web |author=Gorog, A. |url=http://www.animaldiversity.ummz.umich.edu/site/accounts/information/Ateles_geoffroyi.html |archive-url=https://web.archive.org/web/20040224101830/http://animaldiversity.ummz.umich.edu/site/accounts/information/Ateles_geoffroyi.html |url-status=dead |archive-date=February 24, 2004 |work=[[Animal Diversity Web]] |title=''Ateles geoffroyi'' |access-date=October 2, 2007}}</ref>

Spider monkeys are highly agile, and they are said to be second only to the [[gibbon]]s in this respect. They have been seen in the wild jumping from tree to tree.<ref>{{cite book |chapter-url=https://www.academia.edu/392092 |author=Rosenberger, Alfred L. |author2=Halenar, Lauren |author3=Cooke, Siobhán B. |author4=Hartwig, Walter C. |name-list-style=amp |title=Spider Monkeys: The Biology, Behavior and Ecology of the Genus ''Ateles'' |pages=19–49 |publisher=[[Academia.edu]] |date=March 15, 2008 |doi=10.1017/CBO9780511721915.002 |chapter=Morphology and evolution of the spider monkey, genus ''Ateles'' |isbn=9780511721915}}</ref>

{{anchor|Pseudo-penis}}
Female spider monkeys have a [[clitoris]] that is especially developed; it may be referred to as a [[pseudo-penis]] because it has an interior passage, or urethra, that makes it almost identical to the [[penis]], and retains and distributes urine droplets as the female moves around. This urine is emptied at the bases of the clitoris, and collects in skin folds on either side of a groove on the perineal.<ref name="Dixson">{{cite book |last=Dixson |first=Alan F. |title=Primate Sexuality: Comparative Studies of the Prosimians, Monkeys, Apes, and Humans |isbn=978-0-19-954464-6 |publisher=[[Oxford University Press]] |year=2012 |page=364}}</ref> Researchers and observers of spider monkeys of South America look for a scrotum to determine the animal sex because these female spider monkeys have pendulous and erectile clitorises long enough to be mistaken for a penis; researchers may also determine the animal's sex by identifying [[Territory (animal)#Scent marking|scent-marking]] glands that may be present on the clitoris.<ref name="Roughgarden, 2004">{{cite book |last=Roughgarden |first=Joan |year=2004 |title=Evolution's Rainbow: Diversity, Gender, and Sexuality in Nature and People |publisher=[[University of California Press]] |isbn=978-0-520-24073-5 |page=40}}</ref>