Why male bonobos engage in conflicts more often than common chimpanzees 0 12

However, their behavior in social environments differs significantly. Common chimpanzees exhibit extreme aggression: their groups engage in brutal wars with each other, where mutual killings become the norm; moreover, violence can even occur within a single group. For male chimpanzees, the display of strength and aggression means a greater number of offspring — they sometimes force females to mate through violence.

In contrast, bonobos do not wage wars and readily befriend members of other groups. Conflicts, which inevitably arise in any community, are resolved through consensual sexual affection. From an evolutionary perspective, this implies that among bonobos, reproductive advantage should favor the more peaceful individuals. In other words, females tend to avoid aggressive males, preferring calmer partners. (Some researchers even argue that bonobos, like humans, have undergone a process of self-domestication.)

Researchers from the University of Toulouse, along with colleagues from Harvard and other scientific institutions in the U.S., decided to study the behavior of male common chimpanzees and bonobos in their natural habitats. They observed twelve males from three groups of bonobos and fourteen males from two groups of common chimpanzees. Observations were conducted throughout the day, from waking to sleeping; special attention was paid to aggressive actions when a male either attacked someone or was forced to respond to an attack.

The results were unexpected: in an article published in Current Biology, it was reported that male bonobos participated in various skirmishes three times more often than their chimpanzee counterparts. However, in fights, bonobos exhibited greater moderation: they pushed, bit, and hit each other, but fatalities did not occur (mutual killings among bonobos either do not happen or occur so rarely that it is difficult to speak of intentional killing). Bonobos inflicted injuries on each other, but the severity of these injuries remains unknown. Furthermore, male bonobos always fought one-on-one, unlike common chimpanzees, who often band together to attack one of their kind. Male bonobos also rarely exhibited aggression towards females.

It is important to note that female bonobos generally preferred more aggressive males as sexual partners. This means that bonobos do not shy away from aggressive behavior. Most likely, females have a positive view of fighting males as long as their aggression is not directed at them; moreover, a group of female bonobos may unite against a male who begins to behave inappropriately. (Females sometimes use social tricks to smooth over conflicts during mating periods.)

Overall, the differences between bonobos and common chimpanzees can be explained by their living conditions. Common chimpanzees live in conditions of active competition for food, including with gorillas; it is more advantageous for them to exist in small groups, periodically raiding neighbors. Bonobos, on the other hand, inhabit areas where competition for resources is not as fierce, allowing them to unite in larger groups where females form long-term alliances. Despite the fact that male bonobos engage in fights more often than common chimpanzees, the cost of such conflicts is lower for them. In common chimpanzees, a skirmish can end in murder, and one of the males may call upon his companions to fight. These circumstances compel them to control their behavior.

Thus, the results of the observations do not fundamentally change the perception of bonobos: they still appear more peace-loving compared to common chimpanzees. However, it is also not advisable to idealize them, portraying them as 'flower children'; such representations can distort the understanding of primate evolution, especially in the context of changes in their social lives.