Mental Floss

Capuchins Are ‘Kidnapping’ Baby Monkeys of Different Species, And Scientists Are Baffled

The scientists suspect the odd behavior is motivated by boredom.
ByCaLea Johnson|
These adorable guys look like they wouldn‘t steal babies.
These adorable guys look like they wouldn‘t steal babies. | Paul Souders/GettyImages

Capuchin monkeys are mainly known for their intelligence and resourcefulness. However, scientists have come across a strange, new behavior among the primates: child abduction.

Per Smithsonian, Zoë Goldsborough, a researcher at the Max Planck Institute of Animal Behavior, first observed footage of a young male capuchin monkey carrying a baby howler monkey in June 2022—an action that’s never been documented in the species. The findings appear in a study in the journal Current Biology.  

To see if this was a one-off situation, Goldsborough and her colleagues reexamined videos from their motion-sensing cameras placed throughout Jicarón Island near Panama‘s Pacific coast. They found another instance of a male capuchin monkey with a baby howler monkey dating back to January 2022. However, the other males didn’t seem to copy the behavior until five months later.

Their videos captured male capuchin monkeys carrying 11 baby howler monkeys in total. The juveniles wouldn’t hurt the infants nor pay much attention to them. Since male primates can’t produce milk, several babies died of malnutrition. You can watch the footage above.

Scientists are at a loss for what’s making the capuchin monkeys steal babies of a different species. Both monkeys have different diets, so food competition wouldn’t be an issue. The behavior also didn’t seem to evoke a positive social response from peers. 

The study authors suggest the kidnappings might be motivated by boredom. Since capuchins have no predators and very little competition on Jicarón Island, they may be trying to make up for the lack of stimulation by experimenting with new behaviors.

Susan Perry, a primatologist at the University of California in Los Angeles who wasn’t part of the study, disagrees with their conclusion. The expert tells Smithsonian that male capuchin monkeys often steal other capuchin infants. She believes their goal is to build relationships by raising these potential “sidekicks/henchmen.” The primates may be trying to do the same with howler monkey babies. 

The Jicarón Island group of capuchin monkeys is particularly unique. In addition to their strange interest in another species’s young, they’re also the only known monkeys of their kind to use stone tools regularly. 

Read More About Animals:

Home/ANIMALS