Chimpanzees are renowned for their impressive intelligence and tool usage, leading researchers to ponder whether their cultures could also evolve over time like those of humans. A recent interdisciplinary study from the University of Zurich indicates that some of their most intricate behaviors may have been inherited and improved over generations.
Chimpanzees are renowned for their impressive intelligence and tool usage, leading researchers to ponder whether their cultures could also evolve over time like those of humans. A recent interdisciplinary study from the University of Zurich indicates that some of their most intricate behaviors may have been inherited and improved over generations.
In recent years, research has convincingly shown that chimpanzees, similar to humans, transfer elaborate cultural practices such as tool use across generations. However, human culture has evolved significantly over time, from the Stone Age to the Space Age, by adopting new innovations. In contrast, the cultures of chimpanzees have not experienced such dramatic transformations, which implies that only humans possess the extraordinary ability to develop increasingly sophisticated cultures through time.
Yet, some scientists studying wild chimpanzees challenge this view, suggesting that some of the animal’s most intricate technologies—where multiple tools are employed in a series to access concealed food sources—likely evolved cumulatively from previous knowledge.
Uncovering genetic connections
“Due to the perishable nature of most chimpanzee tools, like sticks and stems, there exist limited historical records to substantiate this theory—unlike human technological advancements such as the wheel or computers,” explains Cassandra Gunasekaram from the Department of Evolutionary Anthropology at the University of Zurich, the study’s lead author.
In this new research, a consortium of anthropologists, primatologists, physicists, and geneticists from institutions in Zurich, St. Andrews, Barcelona, Cambridge, Konstanz, and Vienna collaborated to trace genetic connections among chimpanzee populations spanning thousands of years, utilizing novel genetic insights to reveal significant aspects of chimpanzee cultural history in unprecedented ways.
Foundations of cumulative culture
The researchers gathered data on genetic similarity markers—evidence indicating relationships between different chimpanzee groups—along with various foraging behaviors that have been previously identified as culturally learned, across 35 chimpanzee research sites in Africa. They categorized the behaviors into three groups: those that need no tools; those that utilize simple tools, such as employing a leaf sponge to extract water from a tree hole; and the most complex actions that depend on a specific set of tools.
Passing toolsets through generations
For instance, chimpanzees in the Congo area first employ a sturdy stick to dig a deep tunnel through hard soil to reach an underground termite mound,” Gunasekaram elaborates. “Next, they fashion a ‘fishing’ probe by drawing a long plant stem through their teeth to create a brush-like tip, shaping it into a point and skillfully inserting it down the tunnel they have excavated. They then extract it and nibble off any defending termites that have latched onto it.”
“We uncovered the surprising fact that it is the most sophisticated chimpanzee technologies—specifically, the use of entire ‘toolsets’—that exhibit the strongest connections across now isolated populations,” remarks Andrea Migliano, the study’s corresponding author and a professor of evolutionary anthropology at UZH. “This finding aligns perfectly with the prediction that these advanced technologies are rarely created anew or re-invented, making it more probable that they were shared among groups.”
Female migrations as a conduit for innovation
In chimpanzee societies, it is the migrating females, rather than males, who leave to join new groups to prevent inbreeding. This process allows genetic mixing between nearby populations and extends over years, decades, and centuries. The researchers found that these same female migrations could facilitate the spread of new cultural advancements among communities that may not yet possess them.
The study further revealed that when both complex toolsets and their more straightforward counterparts (primarily the components of the toolsets) are found at different study sites, the genetic markers indicate a historical connection between these sites through female migrations. This implies that the more intricate versions developed as a result of gradually refining or enhancing the simpler forms. “These groundbreaking findings offer a fresh perspective on illustrating that chimpanzees possess a cumulative culture, albeit in its early stages,” Migliano concludes.
