Editing Orangutan (section)

=== Tool use and culture ===

[[File:Orangutan using precision grip.jpg|thumb|An orangutan at the [[San Diego Zoo]] using a tool to extract orange-juice concentrate|alt=An orangutan using a stick to pick at a hole in a rock with a cup of orange-juice concentrate.]]

Tool use in orangutans was observed by primatologist [[Birutė Galdikas]] in ex-captive populations.<ref>{{cite journal | last1 = Galdikas | first1 = B. M. F. | year = 1982 | title = Orang-Utan tool use at Tanjung Putting Reserve, Central Indonesian Borneo (Kalimantan Tengah) | journal = Journal of Human Evolution | volume = 10 | pages = 19–33 |doi=10.1016/S0047-2484(82)80028-6}}</ref> Orangutans in Suaq Balimbing were recorded to develop a tool kit for use in foraging which consisted of both insect-extraction sticks for use in the hollows of trees and seed-extraction sticks for harvesting seeds from hard-husked fruit. The orangutans adjusted their tools according to the task at hand, and preference was given to oral tool use.<ref>{{cite book|last1=Fox|first1= E. A.|last2= Sitompul|first2= A. F.|last3= van Schaik|first3= C. P.|date=1999|chapter=Intelligent tool use in wild Sumatran orangutans|editor-last= Parker|editor-first= S|editor2-last= Mitchell |editor2-first=R. W. |editor3-last= Miles|editor3-first= H. L. |title=The Mentality of Gorillas and Orangutans|publisher= Cambridge University Press|pages= 99–116|isbn=978-0-521-03193-6}}</ref><ref>{{cite journal | last1 = van Schaik | first1 = C. P. | last2 = Fox | first2 = E. A. | last3 = Sitompul | first3 = A. F. | year = 1996 | title = Manufacture and use of tools in wild Sumatran orangutans – implications or human evolution | journal = [[Naturwissenschaften]] | volume = 83 | issue = 4| pages = 186–88 | doi = 10.1007/BF01143062 | pmid = 8643126 | bibcode = 1996NW.....83..186V| s2cid = 27180148 }}</ref> This preference was also found in an experimental study of captive orangutans.<ref>{{cite journal | last1 = O'Malley | first1 = R. C. | last2 = McGrew | first2 = W. C. | year = 2000 | title = Oral tool use by captive orangutans (''Pongo pygmaeus'') | journal = Folia Primatologica| volume = 71 | issue = 5| pages = 334–41 | doi = 10.1159/000021756 | pmid = 11093037| s2cid = 19354930 }}</ref> Orangutans have been observed to use sticks to poke at catfish, causing them to leap out of the water so the orangutan can grab them.<ref>{{cite journal|last1=Russon, A. E.|last2= Compost, A.|last3= Kuncoro, P.|last4= Ferisa, A.|year=2014|title=Orangutan Fish Eating, Primate Aquatic Fauna Eating, and Their Implications for the Origins of Ancestral Hominin Fish Eating|journal=Journal of Human Evolution|volume=77|pages=50–63|doi=10.1016/j.jhevol.2014.06.007|pmid=25038033}}</ref><ref>{{cite magazine |url=https://www.wired.com/wiredscience/2011/04/orangutan-tools-fishing/ |title=Orangutans use simple tools to catch fish |author=Bower, B. |magazine=[[Wired (website)|Wired]] |date=18 April 2011 |access-date=5 August 2013 |archive-date=8 July 2013 |archive-url=https://web.archive.org/web/20130708064108/http://www.wired.com/wiredscience/2011/04/orangutan-tools-fishing |url-status=live }}</ref> Orangutan have also been documented to keep tools for later.<ref>{{cite journal|author=Mulcahy, N. J.|year=2018|title=An Orangutan Hangs Up a Tool for Future Use|journal=Scientific Reports|volume=8|issue=1|pages=1–6|doi=10.1038/s41598-018-31331-7|pmid=30150738|pmc=6110832|bibcode=2018NatSR...812900M|doi-access=free}}</ref> When building a nest, orangutans appear to be able to determine which branches would better support their body weight.<ref>{{cite journal|last1=van Casteren, A.|last2= Sellers, W. I.|last3= Thorpe, S. K. S.|last4= Coward, S.|last5= Crompton, R. H.|last6= Myatt, J. P.|last7= Ennos, A. R.|year=2012|title=Nest-building orangutans demonstrate engineering know-how to produce safe, comfortable beds|journal=PNAS|volume=109|issue=18|pages=6873–77|doi=10.1073/pnas.1200902109|pmid= 22509022|pmc= 3344992|bibcode= 2012PNAS..109.6873V|doi-access=free}}</ref>

Primatologist [[Carel van Schaik|Carel P. van Schaik]] and biological anthropologist Cheryl D. Knott further investigated tool use in different wild orangutan populations. They compared geographic variations in tool use related to the processing of ''Neesia'' fruit. The orangutans of Suaq Balimbing were found to be avid users of insect and seed-extraction tools when compared to other wild orangutans.<ref name="Schaik CP 2001">{{cite journal | doi = 10.1002/ajpa.1045 | title = Geographic variation in tool use onNeesia fruits in orangutans | year = 2001 | last1 = van Schaik | first1 = Carel P. | last2 = Knott | first2 = Cheryl D. | journal = [[American Journal of Physical Anthropology]] | volume = 114 | issue = 4 | pages = 331–342 | pmid = 11275962}}</ref><ref>{{cite journal | last1 = van Schaik | first1 = CP | last2 = Van Noordwijk | first2 = MA | last3 = Wich | first3 = SA. | year = 2006 | title = Innovation in wild Bornean orangutans (''Pongo pygmaeus wurmbii'') | journal = Behaviour | volume = 143 | issue = 7| pages = 839–76 | doi = 10.1163/156853906778017944}}</ref> The scientists suggested these differences are cultural as they do not correlate with habitat. The orangutans at Suaq Balimbing are closely spaced and relatively tolerant of each other; this creates favourable conditions for the spreading of new behaviours.<ref name="Schaik CP 2001" /> Further evidence that highly social orangutans are more likely to exhibit cultural behaviours came from a study of leaf-carrying behaviours of formerly captive orangutans that were being rehabilitated on the island of Kaja in Borneo.<ref>{{cite journal | last1 = Russon | first1 = AE | last2 = Handayani | first2 = DP | last3 = Kuncoro |first3 = P | last4 = Ferisa | first4 = A. | year = 2007 | title = Orangutan leaf-carrying for nest-building: toward unraveling cultural processes | journal = [[Animal Cognition]] | volume = 10 | issue = 2| pages = 189–202 |doi = 10.1007/s10071-006-0058-z | pmid = 17160669| s2cid = 6875716 }}</ref>

Wild orangutans in Tuanan, Borneo, were reported to use tools in acoustic communication. They use leaves to amplify the kiss squeak sounds they produce. The apes may employ this method of amplification to [[Deception in animals|deceive]] the listener into believing they are larger animals.<ref name="Hardus ME 2009">{{cite journal | last1 = Hardus | first1 = M. E. | last2 = Lameira |first2 = A. R. | last3 = van Schaik | first3 = C. P. | last4 = Wich | first4 = S. A. | year = 2009 | title = Tool use in wild orang-utans modifies sound production: a functionally deceptive innovation? | journal = Proceedings of the Royal Society B | volume = 276 | issue = 1673| pages = 3689–94 | doi = 10.1098/rspb.2009.1027 | pmid=19656794 | pmc=2817314}}</ref> In 2003, researchers from six different orangutan field sites who used the same behavioural coding scheme compared the behaviours of the animals from each site. They found each orangutan population used different tools. The evidence suggested the differences were cultural: first, the extent of the differences increased with distance, suggesting cultural diffusion was occurring, and second, the size of the orangutans' cultural repertoire increased according to the amount of social contact present within the group. Social contact facilitates cultural transmission.<ref name="Schaik CP 2003">{{cite journal |last1=van Schaik |first1=C. P. |last2=Ancrenaz |first2=M. |last3=Borgen |first3=G. |last4=Galdikas |first4=B. |last5=Knott |first5=C. D. |last6=Singleton |first6=I. |last7=Suzuki |first7=A. |last8=Utami |first8=S. S. |last9=Merrill |first9=M.|year=2003 |title=Orangutan cultures and the evolution of material culture |journal=Science |volume=299 |issue=5603 |pages=102–05 |doi=10.1126/science.1078004 |pmid=12511649|display-authors=etal|bibcode=2003Sci...299..102V |s2cid=25139547 }}</ref>

During a [[Field research|field observation]] in 2022, a male Sumatran orangutan, known to researchers as Rakus, chewed ''[[Fibraurea tinctoria]]'' vine leaves and [[Zoopharmacognosy|applied]] the mashed plant material to an open wound on his face.<ref name=wound>{{Cite journal|display-authors=3 |last1=Laumer |first1=Isabelle B. |last2=Rahman |first2=Arif |last3=Rahmaeti |first3=Tri |last4=Azhari |first4=Ulil |last5=Hermansyah |last6=Atmoko |first6=Sri Suci Utami |last7=Schuppli |first7=Caroline |date=2 May 2024 |title=Active self-treatment of a facial wound with a biologically active plant by a male Sumatran orangutan |journal=Scientific Reports |language=en |volume=14 |issue=1 |page=8932 |doi=10.1038/s41598-024-58988-7 |pmid=38698007 |pmc=11066025 |issn=2045-2322}}</ref> According to [[Primatology|primatologists]] who had been observing Rakus at a nature preserve, "Five days later the facial wound was closed, while within a few weeks it had healed, leaving only a small scar".<ref name=wound/><ref>{{Cite news |last=Davis |first=Nicola |last2= |first2= |date=2 May 2024 |title=Orangutan seen treating wound with medicinal herb in first for wild animals |url=https://www.theguardian.com/science/article/2024/may/02/orangutan-seen-treating-wound-with-medicinal-herb-in-first-for-wild-animals-max-planck-institute-sumatra |access-date=2 May 2024 |work=The Guardian |language=en-GB |issn=0261-3077 |archive-date=2 May 2024 |archive-url=https://web.archive.org/web/20240502152144/https://www.theguardian.com/science/article/2024/may/02/orangutan-seen-treating-wound-with-medicinal-herb-in-first-for-wild-animals-max-planck-institute-sumatra |url-status=live }}</ref>