By Bruce Bower
Just because there’s no patent office in the jungle doesn’t mean that its inhabitants are uninventive. Japanese researchers working in a forested region of Guinea, West Africa, have issued a rare description of a chimpanzee creating a new form of tool use and later instituting improvements to the technique.
In March 2003, a team led by primatologist Shinya Yamamoto of KyotoUniversity saw a 5-year-old male chimp known as JJ sitting in a tree, fishing carpenter ants out of a hollow in the trunk with a long stick. During the researchers’ 27 years of studying chimps almost year-round in Guinea’s Bossou community, they had never observed such behavior.
Bossou chimps prefer to poke long sticks into nests of driver ants on the ground and then swipe the ant-coated tools across their mouths for a quick snack. This behavior is called ant-dipping.
JJ’s initial forays into what’s called ant-fishing, a behavior typical of some chimp communities elsewhere in Africa, achieved limited success. He managed to capture and consume ants on only three of 14 attempts, using roughly 34 centimeter–long sticks. Each attempt lasted 10 to 13 minutes. JJ also received three painful ant bites for his trouble.
Two years later, the enterprising youngster had not given up. Yamamoto found the animal sitting high in a tree fishing for ants with sticks about half as long as those he used in 2003. This time JJ collected and ate ants on two of four attempts, each lasting only a few minutes. Even better, he avoided getting any ant bites.
“This is a rare case of the invention and modification of a new tool-use behavior by a wild chimpanzee,” Yamamoto says. “We do not yet know whether it will disappear or spread among other members of the community.”
His team has never witnessed the immigration of a chimp from another group into the Bossou community, lending support to the conclusion that JJ invented and then amended his ant-fishing technique rather than copying it from another animal.
Yamamoto and colleagues describe their observations in a paper published online May 5 that will appear in an upcoming American Journal of Primatology.
JJ’s ant-fishing innovation apparently relied on what he already knew about ant-dipping, the scientists say. In the trees, he initially wielded sticks of the same length and thickness that he used on the ground. At age 5, young chimps display great interest in learning and practicing tool-use skills, Yamamoto notes. Their avid exploration and trial-and-error experience with tools occasionally lead to innovations.
By 2005, JJ modified his ant-fishing tools based on what he had learned about his insect prey, the researchers propose. Carpenter ants climb up sticks slowly and in small numbers, necessitating the use of relatively short instruments that can be precisely maneuvered. In contrast, driver ants quickly assemble in clumps on sticks, calling for a long, sturdy collection tool.
Ant-fishing and ant-dipping occur in various chimp communities. Each behavior features different tools and techniques, remarks anthropologist William McGrew of the University of Cambridge, in England. Researchers now suspect that these and many other chimp behaviors represent cultural traditions, although little is known about how such actions originate or gain popularity (SN: 11/17/07, p. 317).
JJ’s innovation “amounts to a sort of behavioral mutation that may or may not catch on and spread by social learning,” says McGrew, who has studied several African chimp communities. “It exemplifies the raw material for cultural evolutionary change.”
Watch JJ fish for ants:
