A young bonobo grooming. Photo by Joachim S. Müller/Flickr.com

Kuni found herself face to face with a starling.

Although she’d seen winged creatures fly above her habitat, she finally had one in her hands. A voice urged her to let the bird go. Obeying, she encouraged it to move away from her, perhaps to avoid unwanted trouble.

She nudged it a bit. Then, a bit more.

The starling didn’t move or take flight.

The female bonobo surprised her keepers with what she did next.

With the bird in hand, she climbed to the highest point of the tallest tree and straddled it with her legs. She manually spread the bird’s wings, one at a time, to prepare it for an avian journey.

Next, she tried throwing the bird beyond the limits of the habitat — perhaps similar to the way humans propel a paper airplane.

The bird didn’t make it beyond the barriers of Kuni’s habitat, but keepers presumed it recovered and flew away minutes later because it was nowhere to be found.

Without directly assuming Kuni’s intentions, it seems through her actions that she wanted to help the bird, not hurt it. On some level, she understood the bird’s situation and wanted to solve the problem.

This story from the Twycross Zoo in England, along with many others, highlights the striking emotional resemblance between humans and nonhuman primates. Socially and morphologically, behaviorally and physiologically — we share much in common with our closest ancestors.

Kuni’s actions, originally featured in one of primatologist Frans de Waal’s books, came to mind after reading about new research suggesting physiological differences between bonobos and chimpanzees in efforts to explain why chimps are known to “make war” while bonobos “make love.”

Contrasting these two species contributes to our understanding of what makes us human or essentially, why our temperaments commonly dip into the spheres of love and hate.

In the research, Yerkes Primate Center researchers (at Emory University) found that bonobos’ brains possessed more gray matter in areas that usually play an active role in identifying distress in social contexts. These apes also have larger connections between the brain’s amygdala and anterior cingulate cortex, suggesting a more emotional spin on resolving conflicts among conspecifics when compared to chimpanzees.

Though such research does not distinguish whether brain structure dictates behavior or the other way around, it does give us a better understanding of why bonobos might be more empathetic, and possibly more attentive to others at times.

But, first, let’s briefly look at where our perceptions of bonobos came from.

Bonobos’ anthropomorphic description as “hippies” originates from the species’ ecology and social structure. Or maybe it’s their perfectly parted, black tuft the most hair-savvy humans would envy (see below).

Photo by Kabir/Wikimedia Commons

One of the key differences between bonobos and chimps is the fact that bonobo society is maintained equally among males and females. Female bonds are the strongest in bonobo society, and some even argue that females are more in charge. In addition, bonobos have sex casually, often to dissipate tensions or reinforce affiliations among members of the group. Females routinely rub genitals, kiss and even give oral sex to others of the same sex — it’s just how their social system works.

This all contrasts with chimps, which at times, settle disagreements with violence or destructive dominance displays. Sex isn’t as fluid and mostly reserved for when females are in estrus.

Also, it’s important to keep in mind the environmental conditions in which each species evolved. Chimps, whose range spans across equatorial Africa, inhabit a diversity of landscapes ranging from mixed savannas to dense rainforests. These environments produce different demands on social groups, and thus, different chimp cultures.

Chimps in Senegal, some of my favorite groups to read about, transfer hunting traditions generationally. Sharpening handmade spears with their teeth, they hunt bush babies – nocturnal primates that sleep in tree holes and crevices during the day.

On the other hand, in Jane Goodall’s Gombe chimp group, red colobus monkey meat frequents the menu.

But what about bonobos?

Found only in a shrinking patch of forest in the Democratic Republic of Congo, this endangered species relies mostly on fruit and plant vegetation. Bonobos occasionally feed on insects and small mammals but are not considered active hunters like chimps.

It’s likely that food abundance in bonobo habitats limits extreme competition for food and perhaps the need for active hunting.

In addition to treating each other with great empathy, bonobos’ reposeful demeanors may give them different brains from chimps in another way — perhaps through their ability to learn.

I’m speculating a bit here, but neural brain differences between bonobos and chimps highlighted in the Yerkes research may make it clearer why bonobos represent a few of the most advanced cases of language acquisition in the animal kingdom.

Take the bonobo Kanzi, for instance. With intensive learning and training using lexigrams, he is a formidable lingual opponent to any other animal language contenders (see videos below).

Could it be that Kanzi’s neural wiring contributes to his attentiveness and ability to use symbols and understand language? Is his ability to empathize with others what makes him a good listener and communicator?

It seems to be one of many factors, but certainly not the only prerequisite. As the structure/function debate continues, I still find it fascinating to see our notions of the brain as an impenetrable “black box” turn grayer with time.

Special thanks to my colleague Tim Oleson for bringing the research to my attention.

Twycross Zoo anecdote: de Waal, Frans. “Bonobo: The Forgotten Ape.” University of California Press. 1998.

More background: Angier, Natalie. “Bonobo Society Amicable, Amorous and Run by Females.” http://www.unl.edu/rhames/bonobo/bonobo.htm