https://phys.org/news/2024-04-bonobos-aggressive-previously-thought.html

Chimpanzees and bonobos are often thought
to reflect two different sides of human
nature—the conflict-ready chimpanzee versus
the peaceful bonobo—but a new study
published in Current Biology shows that,
within their own communities, male bonobos
are more frequently aggressive than male
chimpanzees. For both species, more
aggressive males had more mating
opportunities.

"Chimpanzees and bonobos use aggression in
different ways for specific reasons," says
anthropologist and lead author Maud Mouginot
of Boston University. "The idea is not to
invalidate the image of bonobos being
peaceful—the idea is that there is a lot
more complexity in both species."

Though previous studies have investigated
aggression in bonobos and chimpanzees,
this is the first study to directly
compare the species' behavior using the
same field methods. The researchers focused
on male aggression, which is often tied to
reproduction, but they note that female
bonobos and chimpanzees are not passive,
and their aggression warrants its own
future research.
...


https://www.cell.com/current-biology/fulltext/S0960-9822(24)00253-7
Differences in expression of male aggression
between wild bonobos and chimpanzees

Summary
Researchers investigating the evolution of
human aggression look to our closest living
relatives, bonobos (Pan paniscus) and
chimpanzees (Pan troglodytes), as valuable
sources of comparative data. Males in the
two species exhibit contrasting patterns:
male chimpanzees sexually coerce females
and sometimes kill conspecifics, whereas
male bonobos exhibit less sexual coercion
and no reported killing. Among the various
attempts to explain these species differences,
the self-domestication hypothesis proposes
negative fitness consequences of male
aggression in bonobos. Nonetheless, the
extent to which these species differ in
overall rates of aggression remains unclear
due to insufficiently comparable observation
methods. We used 14 community-years of focal
follow data—the gold standard for
observational studies—to compare rates of
male aggression in 3 bonobo communities at
the Kokolopori Bonobo Reserve, Democratic
Republic of Congo, and 2 chimpanzee
communities at Gombe National Park, Tanzania.
As expected, given that females commonly
outrank males, we found that bonobos
exhibited lower rates of male-female
aggression and higher rates of female-male
aggression than chimpanzees. Surprisingly,
we found higher rates of male-male
aggression among bonobos than chimpanzees
even when limiting analyses to contact
aggression. In both species, more aggressive
males obtained higher mating success.
Although our findings indicate that the
frequency of male-male aggression does not
parallel species difference in its
intensity, they support the view that
contrary to male chimpanzees, whose
reproductive success depends on strong
coalitions, male bonobos have more
individualistic reproductive strategies.

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