Capuchin monkeys are stealing howler monkey babies in weird fad
A group of white-faced capuchins on a remote island have started stealing infants from another primate species, and researchers don’t know why
By Sofia Quaglia
19 May 2025
A male white-faced capuchin monkey carrying a baby howler monkey
Brendan Barrett/Max Planck Institute of Animal Behavior
Capuchin monkeys on a remote Panamanian island are abducting babies from howler monkey families, in a first-of-its-kind trend.
The wild population of white-faced capuchins living on Jicarón Island has been monitored with 86 motion cameras since 2017 to capture their sophisticated use of stone tools to crack open hard fruits, nuts and shellfish. Five years into recording the footage, in 2022, a researcher noticed one of the young male capuchin monkeys with an infant monkey from another species clinging to its back. This capuchin, nicknamed Joker, picked up at least four baby howler monkeys over four months, sometimes holding onto them for more than a week.
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At first, the researchers thought it was a case of “one individual who maybe is a little weird or a little quirky”, says Zoë Goldsborough from the Max Planck Institute of Animal Behavior, who spotted the behaviour. “We didn’t expect to find this.”
Then, five months after they saw Joker with an infant, four other young male capuchins were found carrying around howler babies. Over 15 months, the capuchin group took in 11 howler babies younger than four weeks old.
The behaviour spread around the population through social learning, like a “primate fad or fashion”, says Andrew Whiten at the University of St Andrews, UK, who wasn’t involved in the study.
