When it comes to bonobo hierarchy, the ladies stick together. New research out of the Max Planck Institute for Animal Behavior finds that female bonobos team up to keep male bonobos in line, even though the males are larger and stronger than the females.
This type of social structure is uncommon among social mammals in the animal kingdom, and researchers now have a better understanding of why, according to a new study published in Communications Biology.
Bonobos: Queens of the Jungle
According to the Max Planck Institute for Animal Behavior (MPI-AB), male and female bonobos have a strange relationship, at least on a biological level. Among social mammal societies, larger, stronger males are typically the dominant force, controlling mating and food resources.
However, the opposite is true among bonobos. The female bonobos dictate who gets to mate and when. Females also get first dibs on any food sources, while males wait patiently in the treetops above until the females are finished.
Apparently, this behavior, according to Harvard University’s Martin Surbeck, is “totally bizarre for an animal like a bonobo.”
Researchers have debated several theories as to why female bonobos dominate their societies, but to no avail.
“There were competing ideas for how,” said Barbara Fruth from MPI-AB, who has led the LuiKotale bonobo research station for 30 years, in a press release. “None of which had ever been tested in wild bonobos living in the jungles in which they evolved.”
Read More: Study Alters Bonobos’ Reputation as the ‘Make Love not War’ Ape
Forming the Bonobos Female Coalition
Through the new study, an international research team, including Fruth and Surbeck, analyzed 30 years of data from six wild bonobo communities across the Democratic Republic of Congo.
From it, they found some of the first concrete evidence of female bonobos teaming up to outrank males. In about 85 percent of the observations, these female-led teams, known as coalitions, would target male bonobos and force them to submit, structuring the hierarchy towards female dominance.
The team noted that there were 1,786 observed conflicts between male and female bonobos in the data. The female bonobos were victorious in 1,099 of those conflicts.
“To our knowledge, this is the first evidence that female solidarity can invert the male-biased power structure that is typical of many mammal societies,” said Surbeck, in a press release. “It’s exciting to find that females can actively elevate their social status by supporting each other.”
According to the research team, when a coalition forms, you’ll know. They start out by screaming unbearably loudly. They then target the male and chase him through the trees, sometimes leaving him with fatal wounds.
For researchers, it’s challenging to know exactly what triggers a coalition, as it can happen within seconds. In some cases, it’s happened after a male has injured one of their young.
“It’s a ferocious way to assert power,” said Fruth in a press release. “You know why these males don’t try to overstep boundaries.”
The Dominance Spectrum
Even though female dominance is prevalent in most of the observed groups, according to Fruth, this is “by no means the rule.” Instead, the research team looked at female dominance as being on a spectrum.
“It’s more accurate to say that in bonobo societies, females enjoy high status rather than unchallenged dominance,” Fruth said in a press release.
According to the study, female coalitions are just one of the ways female bonobos can stay on top; another includes the ability to hide their ovulation, so males don’t try to monopolize females when they’re in heat. Instead, calmer and less aggressive males who patiently wait seem to be granted access more often than more aggressive males, although more research is needed to confirm this.
“I’m still puzzled why, of all animals, bonobos were the ones to form female alliances. We might never know, but it gives me a glimmer of hope that females of our closest living relatives, in our evolutionary line, teamed up to take the reins of power alongside males,” said Fruth.
Read More: Bonobos Communicate Like Humans, At Least When It Comes to Combining Calls
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
Communications Biology. Drivers of female power in bonobos
A graduate of UW-Whitewater, Monica Cull wrote for several organizations, including one that focused on bees and the natural world, before coming to Discover Magazine. Her current work also appears on her travel blog and Common State Magazine. Her love of science came from watching PBS shows as a kid with her mom and spending too much time binging Doctor Who.
