Capuchin Monkey Soap Opera in Costa Rica

Sex and political intrigue: That’s not the latest scandal to hit Washington, D.C., but rather Susan Perry’s summation of what she has witnessed every day for the past 25 years.

Perry is an anthropologist and National Geographic explorer who has spent most of her career studying the social behaviors of capuchin monkeys in Costa Rica. After all these years, Perry is still intrigued by how the monkeys form alliances.

“Capuchins invent special bond-testing rituals—ways of testing whether somebody is really, truly, their friend and is dependable. And these are behaviors like poking one another deep in the eye socket or sticking their fingers up one another’s nose or special games that involve biting chunks of hair out of somebody’s face and passing it back and forth from mouth to mouth,” Perry explains. With friends like that, who needs enemies?

These alliances are critical since capuchins frequently face lethal threats from their actual enemies. Infanticide is a common type of aggression and is often carried out by a new male who “comes into a group from the outside and takes over the leadership and breeding role,” Perry says. Nursing prohibits females from conceiving more offspring, so by killing the infants, the new male can begin mating with the females and building his empire all the sooner.

Perry’s team recently watched as one of their favorite babies, Huxley, was killed by a male newcomer. Perry recalls that the male “just walked over and calmly administered a hard bite to this baby’s head and then let the mother go. He didn’t seem angry or at all riled up about it, he just acted like he had a job to do.”

While killing may be business as usual for the capuchins, watching the deaths has more of an emotional impact on Perry. “We’ve been studying these monkeys for so long that we’re really pretty attached to all of them. I’m able to walk through the forest and run into individuals I know personally, and I can predict 99 percent of the time what they’re going to do next.” This level of connection may make the deaths and struggles more difficult to bear, but it has its upside, too. For Susan Perry, “it’s a really, really satisfying kind of relationship to have.”

To learn more about Perry’s relationships with the capuchins and the monkeys’ relationships with one another, listen to Perry’s interview on National Geographic Weekend.

Changing Planet


Meet the Author
Nora Rappaport is a producer and editor on National Geographic's Science and Exploration Media team. She produces content that highlights the awe-inspiring work of National Geographic explorers around the globe. When not working with her colleagues to inspire people to care about the planet, Nora can be found hanging out with any number of dogs.