Spider monkeys search for food by exchanging secret knowledge.

For seven years, researchers observed Geoffroy’s spider monkeys on the Yucatán Peninsula in Mexico, uncovering a sophisticated system of exchanging “insider” information about food among these .
A team of scientists from Heriot-Watt University, the University of Edinburgh (UK), and the National Autonomous University of Mexico documented how moved between groups, sharing information about where to find the ripest fruits.
The observations made by ecologists, zoo psychologists, and biologists shed new light on the unique social behavior of this species, where group members form small subgroups and then reunite in various combinations to enhance knowledge sharing.
Researchers noted that the primates often banded together in subgroups of three or more individuals to more effectively exchange information about the locations of trees bearing ripe fruit.
According to the study, the animals not only supplemented each other’s knowledge but also “combined information in such a way as to create new knowledge,” the scientists wrote in their report for the journal njp Complexity.

“For example, one group indicated the location of a food source, while another provided the timing of its fruiting,” the scientists explained. Interestingly, one subgroup may never gather twice to search for food, as reported by The Guardian.
The researchers assert that this is a compelling example of “collective intelligence in natural conditions.”
Dr. Matthew Silk, an ecologist at the University of Edinburgh, emphasized: “This is not random communication. It is a sophisticated system for exchanging insider information about where the best fruit trees grow in the forest environment.”
The scientist also shared that he and his colleagues tracked the movements of individual monkeys and mapped their core areas, which each individual knows well. “Some parts of the forest are known to several monkeys, like the most popular restaurant in town, while other areas are known only to one or two monkeys, like a hidden treasure,” he added.
Another co-author of the study, Ross Walker, a graduate student at Heriot-Watt University, developed a mathematical modeling method to analyze this system. It turns out there is an optimal compromise between monkeys staying together and spreading too thin. “It’s best when primates explore different areas but meet often enough to exchange the knowledge they’ve gained,” the researcher said.
Geoffroy’s spider monkey, or the black-handed spider monkey, is currently endangered. Researchers believe that their systematic search for food is one of the key factors helping these animals survive.
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