On an isolated island in Panama, white-faced capuchin monkeys have developed unprecedented behavior. A recent study reveals how this social practice spread among young males.
The white-faced capuchins of Jicarón Island are known for their use of stone tools. This ability, observed since 2017, has been studied using camera traps. In 2022, a surprising new discovery was made: a young male was carrying a baby from another species, a howler monkey, on its back.
A young male capuchin carrying a baby howler monkey.
Credit: Brendan Barrett / Max Planck Institute of Animal Behavior
Zoë Goldsborough, a doctoral student at the Max Planck Institute, identified this behavior as a first. Analysis of the footage showed it was not an isolated incident. Four different howler monkey babies were carried by the same individual, nicknamed Joker, over several months. A behavior that could be described as kidnapping.
Researchers initially considered the adoption hypothesis. However, most adoptions are carried out by females. The uniqueness of this case led scientists to investigate further. They discovered the behavior had spread to four other young male capuchins.
Over 15 months, five capuchins transported 11 howler monkey babies. The footage shows the young males going about their usual activities with the babies clinging to them. This practice, though seemingly without benefit for the capuchins, appears to have been socially transmitted among the young males.
The consequences for the howler monkey babies were tragic, with at least four documented deaths. Researchers emphasize that the capuchins did not mistreat the babies but were unable to care for them. This social tradition raises questions about the origins of cultural behaviors in animals.
The study suggests that the absence of predators and the easy living conditions on the island might explain the emergence of such traditions. The capuchins, with plenty of free time, seem to be exploring new social interactions. This discovery opens new perspectives for studying animal cultures.
Researchers continue to analyze data to understand the evolution of this tradition. Its impact on the already threatened howler monkey population could become a conservation issue. This study provides a unique insight into the dynamics of cultural behaviors in wild animals.