Skip to content. Skip to more features. Skip to most popular. Skip to footer.


Monkey Business


By Jean-Paul Renaud

Published Jul 1, 2015 8:00 AM


Photo by Sebastian Hernandez.

Says park ranger Manrique Montes: “Doña Susan,” as she’s respectfully referred to, “is our compañera de lucha,” or sister-in-arms.

“We don’t consider her just another foreign researcher,” he says. “She’s part of our team. She’s helped us understand how the reserve works and how the monkeys are a key part of its health.”

In The Jungle: Chapter 3

Abby’s splintered group spent much of April 2003 lost in the forest, longing to return to their group life.

Capuchins live in groups ranging from as small as five to as large as 40. Their social structure is complex, based on trust, power, lust and greed. And at the top of each group is a strong alpha male, always plotting, building alliances and, most important, mating. If the alpha remains in power long enough, Perry discovered through her study of Rambo’s group, he eventually allows others to start mating in order to avoid inbreeding.

The melee that destroyed Abby’s group changed the forest’s delicate dynamic and introduced new characters into this 25-year-old soap opera. Jester and Tattle, two low-ranking females tired of being bullied, led their descendants to form a leaner group, which researchers nicknamed “Flake’s group.”

Leaderless and in need of an alpha male, this group turned to some new characters. Four brothers in search of a group to lead, “determined to conquer the world,” as Perry describes them, stumbled upon the newly formed Flake’s group in October 2003. Once the brothers had secured their control over Flake’s group and driven off all of their enemies, they turned on one another. William Shakespeare couldn’t have written it any better.

There was betrayal. Deceit. Exile. The sole survivor and new leader of Flake’s group, Heinrich, had come from a family of 27 paternal siblings when he set out with his brothers to make his own mark on the forest. He was strong, smart and resourceful —just what Flake’s group needed from a leader.

Heinrich held power for four years before being deposed in a bloody confrontation with one of his own group members, Quixote. The two fought so fiercely that Heinrich suffered injuries that deformed his face. Although he lost the battle and his throne, he survived, and today he’s seen as the group’s elder statesman — a proven leader who still protects his group.

While the battles were stressful for Perry and her team to watch, there was a valuable discovery to be made: For capuchins, blood is thicker than water — as long as it’s convenient. The battles for power that ensued after the collapse of Abby’s groups proved that monkeys related to one another stick together and defend one another against foes.

New discoveries are still emerging, thanks to Flake’s group. Currently, Brendan Barrett, a doctoral student under Perry’s supervision, is using the group to examine whether and how the capuchin can transfer knowledge to a fellow monkey. The experiment currently under way exposes them to a fruit that is difficult to open; once one monkey has unlocked the fastest way to break into the center, the researcher documents how that technique is spread among others in the group.


Photo by Jamin Shih

“There’s always a new mystery,” Perry says. “These monkeys are so complex that we’ll never be done understanding how they function.”

Adventures In Primatology

The researcher family that has developed through the Monkey Project is now spread throughout the world.

There have been at least six “Monkey Project weddings” — researchers who have met during their fieldwork and fallen in love. Facebook groups have sprung up. Email blasts keep everyone in touch. And monkey drama is shared and devoured by project members throughout the world.

Perry’s biological family is not to be left out. Her husband and daughter, now 16, still come to Costa Rica every summer. And the Perry music tradition lives on. Primatologist and daughter now play violin duets in local restaurants and public schools, as well as under the bodega, the hangar that houses her researchers. Even Jimenez, the loyal driver and a lover of classical music, attends.

Amid the growing threat of climate change and human interference, Perry says she will continue to study her monkeys and to educate the local community on the importance of ecology as long as she is able.

“I know the day will come when I won’t be able to do this fieldwork, and I do dread that,” she says. “But every new answer inspires more questions, and each additional year of research enables us to address more mysteries. Finally, we’re ready to tackle some of the really big questions that were impossible to ask in the early years. We don’t know what the future holds for these monkeys, but we can be sure it won’t be just more of the same.”