Chimpanzee Culture and Tool Use: A Window Into Cumulative Evolution
Research reveals the role of social learning and genetics in the development of tool-based foraging techniques in chimpanzees.
Bridging the Cultural Divide
Chimpanzees, long regarded as close relatives of humans, exhibit behaviors that hint at a form of cultural transmission. Researchers have uncovered a fascinating connection between genetic relatedness and advanced tool use among chimpanzee populations in East and Central Africa. This discovery suggests that chimpanzees may possess a form of cumulative culture—a characteristic previously thought unique to humans.
The findings, published in Science1, reveal that these apes demonstrate a remarkable ability to innovate, adapt, and socially transmit knowledge across generations and populations.
Sophisticated Tools for a Snack
In the rain-forests of the Congo, chimpanzees display an impressive array of foraging techniques. One such behavior involves crafting a tool to fish termites out of their subterranean nests. The apes poke holes in the ground with sticks, fashion lures by stripping plant stems, and use the modified tools to extract their meal.
“It’s difficult to imagine that it can just have appeared out of the blue,” remarks Dr. Andrew Whiten, a cultural evolution expert from the University of St. Andrews.
This level of ingenuity and problem-solving raises an intriguing question: Are these behaviors the result of individual creativity, or do they reflect the accumulation of knowledge passed down through social learning?
Evidence of Cumulative Culture
Culture, as seen in various species, refers to socially learned behaviors. However, cumulative culture involves building upon these behaviors over time, creating techniques too complex for a single individual to devise.
Chimpanzees using rocks as hammers and anvils to crack nuts, for example, might initially seem spontaneous. However, researchers argue that such methods likely require social learning. Dr. Whiten’s team suggests that the sophisticated foraging techniques observed in some chimpanzee groups are an example of cumulative culture.
“Chimpanzees have a ‘tiny degree of cumulative culture,’” Whiten and colleagues write, challenging the long-standing assumption that this trait is exclusive to humans.
Genetic Connections and Cultural Transmission
The study, led by evolutionary biologist Cassandra Gunasekaram, analyzed the genetic data of 35 chimpanzee populations across East and Central Africa. The researchers found a strong correlation between genetic relatedness and the complexity of tool use.
Chimpanzee groups exhibiting advanced tool-based behaviors, such as sequentially using tools to extract food, were closely related to each other and to populations using simpler versions of these techniques. In contrast, populations that used no tools or rudimentary tools showed less genetic relatedness.
“Sophisticated foraging tricks might need some sort of social transmission and social learning, an exchange of ideas between different places,” Gunasekaram explains.
The Role of Migration in Spreading Culture
Female chimpanzees, which often migrate between groups to reproduce, may act as carriers of culture. By introducing new behaviors and innovations to their adopted communities, they facilitate the spread of tool-use techniques and the gradual enhancement of these methods over generations.
“The ‘modestly cumulative culture’ of chimpanzees depends on migration between local populations, where mingling allows for social learning,” notes Dr. Peter Richerson of the University of California, Davis.
A Debate Over Cumulative Culture
Not all researchers agree on the implications of these findings. Dr. Claudio Tennie, an expert in ape culture, argues that the behaviors observed in chimpanzees could still arise independently without social learning.
“What I’ve been saying for all these years is ‘You’re underestimating the apes’ cleverness!’” Tennie states, suggesting that even complex foraging techniques may be within the cognitive capabilities of individual chimpanzees.
However, Whiten counters that experiments, such as offering chimpanzees complex straws to drink juice, provide strong circumstantial evidence that these behaviors rely on cultural transmission.
Insights Into Human Evolution
Understanding chimpanzee culture provides valuable insights into the origins of human cumulative culture. While chimpanzees’ abilities are modest compared to humans, their behaviors may represent the early stages of a process that culminated in the intricate cultural achievements of modern societies.
By examining the genetic and social dynamics underlying chimpanzee tool use, researchers can better understand how humans developed the capacity for cumulative innovation—an ability that underpins everything from medicine to engineering.
Rewriting the Narrative on Culture
Chimpanzees’ tool use and social learning challenge the notion that cumulative culture is exclusive to humans. While the debate continues over the extent of this ability in apes, the evidence points to a complex interplay of genetics, migration, and social transmission. These findings not only reshape our understanding of chimpanzee behavior but also offer a glimpse into the evolutionary pathways that led to human culture as it exists today.
Richerson, P. J., & Boyd, R. T. (2024). Culture in humans and other animals. Science (New York, N.Y.), 386(6724), 846–847. https://doi.org/10.1126/science.adt8896