Chimpanzee innovations may be low tech by human standards, but they get the job done and are gradually improving and spreading, a new study co-authored by famed primatologist Jane Goodall suggests.
The study, published in the latest issue of Current Anthropology, presents the first documented case of successful transmission of a novel cultural behavior — ant fishing — between wild chimpanzee communities.
"Ant fishing in this case is using twigs, leaf midribs or grass probes to extract carpenter ants from their nests in living trees or dead wood," lead author Robert O'Malley, an assistant professor of anthropology at Kenyon College, told Discovery News.
Chimps trim their twig tools at the end, with side twigs and excess bark often removed, he added.
A clever and popular female chimp named Trezia somehow figured out this technique. Trezia, from the Mitumba chimp community of Gombe National Park, was transferred to the park's Kasekela chimpanzee community, where ant fishing is now all the rage among females around her age.
"Trezia ascended the Kasekela hierarchy more quickly than most immigrants, who often remain a bit peripheral in the community after emigrating, and she was not skittish around other chimpanzees," O'Malley said. "All this suggests she would have been a viable model for younger cohorts."
The Kasekela chimps had a win-win because, in addition to gaining smart Trezia, they also had the perfect classroom to learn from her: a relaxing spot called Hilltop.
"Kasekela chimpanzees tend to take a siesta at Hilltop for a few minutes or a few hours when they pass through the area, so it provides a relaxed social context and perhaps a good learning environment," explained O'Malley.
"There is very little undergrowth so visibility is very good," he said. "Most importantly, there are multiple fishing sites in visual proximity, including at least one Camponotus (type of ant) nest in a particular place at Hilltop."
Females tend to be the chimp versions of Bill Gates or the late Steve Jobs when it comes to innovations, however low-tech. That's just because "in chimpanzees, females are the sex that will typically disperse from their natal group at sexual maturity, so any cultural transmission between communities is most likely to occur through female transfer."
Trezia is only the latest chimp to gain fame and food fortune among her own kind. A proficient nut-cracking female chimp in Liberia might have spread her know-how to others.
Then there is Imo, a Japanese macaque who learned to wash sweet potatoes.
"Imo also learned to throw scattered rice grains into the sea to separate them from sand, and a few other tricks as well," O'Malley said, adding that others within her own group observed her success and soon copied her methods.
Males also come up with their own useful techniques that appear to spread within their groups. A dramatic example concerns a male chimp living in Bossou, Guinea. He learned to deactivate snares, rescuing other chimps and setting off others before they harmed animals.
Vernon Reynolds, a primate expert who serves as an adviser at the Budongo Forest Research Project, told Discovery News that while the Bossou findings are "exceptional ... our chimps at Budongo make alarm calls at snares and also, on one occasion at least, our alpha male removed a snare from an adult female."
While chimpanzees in protected parks are better able to spread their knowledge, humans are sadly hurting the overall ability of these fellow primates to improve their lot in life through shared innovations.
"The many chimpanzee communities across Africa that have already disappeared have taken any unique cultural patterns of behavior with them," O'Malley said. "As the remaining populations become more isolated, there will be fewer opportunities for individuals to transfer between communities, which limits opportunities for both gene flow and for cultural diffusion."