Chimpanzees Improve Tool-Using Skills Into Adulthood, Study Finds

Scientists have discovered that the highly intelligent and social chimpanzee continues learning and honing the use of tools well into adulthood. This ability could be vital for the evolution of complicated and varied tool use.

In the study, the researchers said tool use is rare in animals, but they discovered that chimpanzees employed hand grips utilizing more than one finger as they got older.

“Such hand grips emerged at the age of 2, became predominant and fully functional at the age of 6, and ubiquitous at the age of 15, enhancing task accuracy. Adults adjusted their hand grip based on the specific task at hand, favoring power grips for pounding actions and intermediate grips that combine power and precision, for others,” the study’s authors wrote. “Highly protracted development of suitable actions to acquire hidden (i.e., larvae) compared to non-hidden (i.e., nut kernel) food was evident, with adult skill levels achieved only after 15 years, suggesting a pronounced cognitive learning component to task success.”

Humans have the ability to keep learning throughout their lives, and it is thought that this is why they are able to use tools with such flexibility. This ability has been an essential part of the evolution of human culture and cognition, a press release from the Public Library of Science (PLOS) said.

The research team examined whether chimpanzees also have this ability by looking at how their tool techniques evolved with age. They recorded 70 chimps of various ages retrieving food with sticks over the course of several years in the wild at Côte d’Ivoire’s Taï National Park.

The chimpanzees became more skilled at using suitable finger grips in handling the sticks as they got older and continued honing their gripping techniques well into adulthood.

Some more advanced skills like using sticks to pull insects out of places that were difficult to reach or adjusting their grip for different tasks were not completely developed until the age of 15. This suggests the more complex skills are not only a matter of physical maturity, but a product of learning capacities for novel technological methods that progress as they age.

The team found that retention of learning capacity as adults seems to be a useful attribute for species that use tools — an important insight into chimpanzee and human evolution. The authors noted that additional study would be necessary to fully understand the learning process of chimpanzees, such as how memory and reasoning play a role and how important experience is in comparison to instruction from peers.

“In wild chimpanzees, the intricacies of tool use learning continue into adulthood. This pattern supports ideas that large brains across hominids allow continued learning through the first two decades of life,” the authors said in the press release.

The study, “Protracted development of stick tool use skills extends into adulthood in wild western chimpanzees,” by Mathieu Malherbe and colleagues from France’s Institute of Cognitive Sciences, was published in the journal PLOS Biology.