Capuchin Monkey Snatches Baby Howler Monkey in Unusual Trend

Capuchin monkeys on a remote island in Panama are gaining attention as they acquire infants from the Howler monkey species.

A wild group of white-faced capuchins (Cebus capucinus imitator) residing on Zikaron Island has been under observation with 86 motion cameras since 2017. Researchers are studying their complex use of stone tools to open hard fruits, nuts, and shellfish. By 2022, five years into their study, they observed one young male capuchin, nicknamed Joker, frequently carrying a baby howler monkey (Alouatta coibensis) for over four months, sometimes for weeks at a time.

Initially, researchers speculated this might be an unusual behavior. According to Zoë Goldsborough from the Max Planck Institute for Animal Behavior, “I didn’t think we would find this.”

Months later, after observing Joker with the baby, four other young capuchins were spotted carrying howler infants as well. Over a span of 15 months, the capuchin group acquired 11 howler babies under four weeks old.

Researchers believe this behavior may spread through social learning, likening it to “primates and fashion,” notes Andrew Whiten, who was not involved in the study, from St Andrews University in the UK.

Mature female monkeys might adopt abandoned infants from other species as a way to practice nurturing. However, in this case, it’s immature male capuchins engaging in the behavior. Instead of merely adopting abandoned young, they appear to be actively taking howler infants from their families. Although there is no direct footage of theft, researchers documented a capuchin preventing a howler baby from escaping, while howler parents called out to find their infants, showcasing the capuchins’ defensive behavior.

The abducted infants are likely too young to survive without maternal care, leading to their eventual death from malnutrition. Investigators have observed at least three howler infants being carried even after they have died.

Learning from peers can be advantageous. Even if the behavior does not yield any tangible benefits, Whiten suggests it may simply be an expression of curiosity.

The capuchins on Jikarón Island face little competition and lack natural predators, allowing them to explore new behaviors, perhaps as a response to ennui. Goldsborough notes that Joker, who is frequently seen utilizing tools, may embody this trend. “If a tradition exists, individuals are likely to imitate other behaviors as well.”