Humans have always loved the idea that we’re special. We build cities, write poetry, and send rockets into space. But every now and then, science reminds us that we’re not as unique as we’d like to think.
Case in point: a new study from researchers at Utrecht University and Universidad Carlos III de Madrid found that our closest living relatives, chimpanzees and bonobos, organize their social lives in ways that look strikingly familiar. They have best friends. They have acquaintances. They even narrow their social circles as they get older, just like many of us do.
The researchers analyzed grooming behavior across 24 groups of chimpanzees and bonobos. Grooming isn’t just about hygiene for these animals. It’s their way of maintaining relationships, strengthening bonds, and figuring out who matters to them. Using a mathematical model, the team examined how individuals distributed their limited time and social effort among other group members.
What they found was a pattern that should feel incredibly familiar to anyone with a phone full of contacts and a small handful of people they actually text back.
Most apes devoted the bulk of their grooming time to a small number of preferred partners while keeping lighter connections with many others. This layered structure mirrors the way human social circles work. You have your inner circle, maybe two or three people who really know you. Then there’s a wider ring of friends you catch up with occasionally. And finally, there’s the vast periphery of acquaintances who exist somewhere in the background of your social life.
Here’s where it gets even more interesting. The researchers noticed that apes living in larger groups tended to be more selective about where they invested their social attention. Sound familiar? In big cities, people often have fewer close friends than those living in smaller communities. It’s a trend that’s been documented in human social networks, and now it shows up in primate groups too.
But the two species didn’t behave identically. Bonobos distributed their grooming time more evenly across group members, creating a more egalitarian social network. Chimpanzees, on the other hand, concentrated more effort on a smaller number of favored companions. This aligns with what we already know about their broader social behavior. Chimpanzee societies tend to be more hierarchical and competitive, while bonobo groups are known for their fluid relationships and cooperation across boundaries.
The age factor added another layer of intrigue. As chimpanzees aged, they increasingly invested in fewer social partners, narrowing their inner circle. Bonobos didn’t show the same pattern. One researcher suggested this might be because bonobos live in more fluid social systems where bonds transcend group boundaries in ways that chimpanzees simply don’t exhibit.
Lead author Edwin van Leeuwen put it plainly: the findings suggest that similar principles govern how social relationships are formed and maintained across multiple species. That’s a pretty significant statement. It implies that the way we build and manage relationships isn’t some uniquely human invention. It’s deeper than that. It’s evolutionary.
This raises uncomfortable questions for anyone who likes to think of human society as a singular achievement. If chimps and bonobos are out here managing friend groups, navigating social hierarchies, and allocating their limited social energy in ways that look eerily like our own, then perhaps the foundations of complex sociality run much further back in our family tree than we typically acknowledge.
Of course, there’s still more than one way to do this. The differences between chimpanzees and bonobos show that evolution has produced multiple strategies for managing social connections. What works for one species isn’t necessarily the blueprint for all others.
Still, there’s something slightly humbling and oddly comforting about this. We’re not as alone in our social complexity as we might think. Our closest relatives are out there in the forest, grooming their best friends, navigating the nuances of group dynamics, and probably dealing with the same exhausting reality that time and energy for social connection are finite resources.
Maybe we’re not so special after all. Or maybe that’s exactly what makes us special.
