Tool use among orangutans was first documented by Carel van Schaik. In 1994, Carel observed orangutans developing tools to help themselves eat, while conducting field work in Gunung Leuser National Park, in the northwest Sumatra.

Specifically the orangutans were using sticks to pry open pulpy fruits that have “Plexiglas needles” capable of delivering a painful jab covering them. Using the tools, the orangutans were getting past handling the prickly husk and into the nutritious fruit. From an anthropological viewpoint, tool use represents an aspect of culture, since the entire group participates in a behavior that has developed over time. One unique thing to clarify is that only Sumatran orangutans have been observed to use tools, not orangutans from Borneo.

Recently, Gerd Schuster co-author of Thinkers of the Jungle: The Orangutan Report, took this photograph of,

“a male orangutan, clinging precariously to overhanging branches, flails the water with a pole, trying desperately to spear a passing fish… The extraordinary image, a world exclusive, was taken in Borneo on the island of Kaja… This individual had seen locals fishing with spears on the Gohong River. Although the method required too much skill for him to master, he was later able to improvise by using the pole to catch fish already trapped in the locals’ fishing lines.”

Pretty awesome image, no? If you wanna read more about orangutan tool use, here are three papers on the topic:

Schaik, C.P., Fox, E.A., Sitompul, A.F. (1996). Manufacture and use of tools in wild Sumatran orangutans. Naturwissenschaften, 83 (4), 186-188. DOI: 10.1007/BF01143062

Call, J., Tomasello, M. (1994). The social learning of tool use by orangutans (Pongo pygmaeus). Human Evolution, 9 (4), 297-313. DOI: 10.1007/BF02435516