04-24-2023

Study: Mean chimpanzees fare better in life than nice ones

Earth.com staff writer

In a world where the struggle for power and dominance is often characterized by aggressive and forceful behavior, new research on chimpanzees offers valuable insight into how brutish actions can lead to successful outcomes.

Scientists have long been fascinated by the power dynamics in both human and animal societies, and the latest study on chimpanzees offers further evidence that aggressive tactics might, in fact, be an effective way to climb the social ladder.

The research, which will be published on April 24 in the journal PeerJ Life and Environment, focused on the behavior of male chimpanzees in Gombe National Park, Tanzania.

The study found that male chimps exhibiting bullying, greedy, and irritable personalities were more likely to achieve higher social status and sire more offspring than their more deferential and conscientious counterparts. This finding raises the question: if aggression and dominance are so advantageous, why isn’t every chimp a bully?

How the study was done

A team of researchers led by Alexander Weiss of the University of Edinburgh and Anne Pusey of Duke University sought to answer this question by studying 28 male chimps living in Gombe National Park.

The study built upon previous work by the same researchers, which had identified variations in chimpanzee social behavior, ranging from highly sociable to solitary and from easy-going to overbearing.

Tanzanian field researchers with extensive knowledge of the chimpanzees conducted personality assessments based on years of near-daily observations. They recorded each chimp’s behavior and interactions with other members of the group, providing a comprehensive picture of the social dynamics within the community.

The results of the current study revealed that male chimpanzees with specific personality traits, namely a combination of high dominance and low conscientiousness, were more successful than others in terms of social status and reproduction, according to lead author Professor Joseph Feldblum.

Study results leave more questions than answers

While it may not come as a surprise that bullying behavior can provide certain advantages in the animal kingdom, recent findings on the relationship between personality traits and reproductive success in chimpanzees have left researchers with more questions than answers.

The new research begs the question: if males with specific personality tendencies are more likely to rise to the top and reproduce, passing the genes for those traits onto their offspring, why do personality differences exist at all? “It’s an evolutionary puzzle,” said Professor Feldblum.

One longstanding theory proposes that different personality traits may offer advantages at various points in an animal’s life. For example, while aggressive behavior might benefit young male chimpanzees, it could become detrimental as they grow older. Alternatively, certain traits could be a liability in youth but an asset in old age.

“Think of the personality traits that lead some people to peak in high school versus later in life,” explained Weiss. “It’s a trade-off.”

Understanding the factors that shape chimpanzee personalities

However, when the research team analyzed 37 years of data, including some of Jane Goodall’s early work in Gombe in the 1970s, they found that the same personality traits were linked to high rank and reproductive success throughout the chimpanzees’ lifespan. This discovery suggests that other factors must account for the diverse range of personalities observed in chimpanzees.

One possibility is that the “best” personality to possess varies depending on environmental or social conditions, or that a trait beneficial to males might be costly to females, according to Feldblum. If this were the case, then “genes associated with those traits would be kept in the population,” Weiss added.

Decades ago, the idea that animals even possessed personalities was considered controversial. Jane Goodall herself faced accusations of anthropomorphism when she described some Gombe chimpanzees as “bolder” or “more fearful” than others, or as “affectionate” and “cold.”

Since then, however, scientists have discovered evidence of distinct personalities in a wide variety of animals, from birds to squid. These personality traits, characterized by idiosyncrasies and ways of relating to the world, remain relatively stable over time and across situations.

Weiss claims that personality assessments for animals have proven to be as consistent from one observer to the next as similar measures for human personality. “The data just don’t support the skepticism,” Weiss concluded.

The implications of this research extend beyond the world of chimpanzees, raising important questions about the nature of power dynamics in various social contexts. If aggressive and forceful behaviors are indeed effective strategies for achieving dominance, what does this say about our own human societies and the ways in which we interact with one another?

As scientists continue to explore the complex relationships between personality, aggression, and success in both human and animal populations, these findings serve as a reminder of the potential dark side of the struggle for power. Perhaps the key to understanding and improving social dynamics lies in further examination of the role that individual personalities play in shaping the behavior of groups and communities.

More about chimpanzee culture

Chimpanzees (Pan troglodytes) are highly intelligent and social animals native to the forests of central and west Africa. They share around 98% of their DNA with humans, making them our closest living relatives.

Over the years, extensive research on chimpanzees has revealed fascinating insights into their societies, culture, and behaviors. Some key aspects of chimpanzee societies and culture include:

Chimpanzee communities are organized in a complex, fluid social structure called a fission-fusion society. These communities can include anywhere from 20 to 150 individuals. Members of a community form temporary sub-groups, or parties, that change in size and composition over time. These sub-groups can split (fission) or merge (fusion) depending on factors such as food availability, social preferences, and mating opportunities.

Hierarchy and dominance

Chimpanzee societies are characterized by a dominance hierarchy, with males typically being more dominant than females. A dominant male, known as the alpha male, asserts his authority through displays of aggression, grooming, and coalition-building. Dominance can be established and maintained through physical strength, intelligence, and social skills.

Communication

Chimpanzees communicate using a range of vocalizations, gestures, and facial expressions. They also engage in grooming, which serves as a means of social bonding and reinforcing relationships. Their communication repertoire includes various calls, such as pant-hoots, grunts, and screams, which can convey emotions, intentions, and information about their surroundings.

Tool use

Chimpanzees are known for their impressive tool-making and tool-using abilities. They have been observed using sticks to extract termites from their mounds, leaves as sponges to absorb water, and stones to crack open nuts. These behaviors indicate a high level of cognitive ability and problem-solving skills.

Chimpanzees are omnivorous, with a diet that includes fruits, leaves, seeds, insects, and occasionally meat. They have been known to hunt cooperatively, particularly when preying on small primates like colobus monkeys. Food sharing is a common practice among chimpanzees, particularly among males, and is thought to play a role in reinforcing social bonds, asserting dominance, and securing mating opportunities.

Cultural transmission

Researchers have identified various regional differences in chimpanzee behaviors, such as grooming styles, tool use, and foraging techniques, which are passed down through generations via social learning. This transmission of behaviors and traditions within and between communities is considered evidence of culture in chimpanzee societies.

Altruism and empathy

Chimpanzees have been observed displaying altruistic behavior, such as consoling one another after conflicts, adopting orphaned infants, and sharing food. These behaviors suggest that, like humans, chimpanzees possess a capacity for empathy and emotional intelligence.

Overall, chimpanzee societies and culture provide valuable insights into the evolutionary origins of human social behavior, cognition, and culture. Studying these close relatives of ours helps us better understand our own species and the factors that have shaped our development.

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