Spider monkeys found to share ‘insider knowledge’ to help locate best food | Animal behaviour

Spider monkeys share tips on where to find food by changing social groups in an “intelligent insider knowledge sharing system,” research shows.

They were observed to frequently change subgroups of three or more individuals in a way that allowed them to share information about the location of fruit trees and when they would ripen.

This meant they could not only complement each other’s knowledge, but also “combine their information in ways that produce new knowledge”, according to the research.

The report, published in the journal njp Complexity, says: “An example would be if a subset of individuals contributed to the location of a food source and another subset contributed to the timing of that source’s fruiting.

“The combined knowledge of the two subsets of individuals would be synergistic in the sense that it would allow all to exploit the food source based on its location and timing.”

He concluded that the evidence constituted a “compelling example of collective intelligence under natural conditions.”

The study, involving scientists from Heriot-Watt University, the University of Edinburgh and the National Autonomous University of Mexico, draws on seven years of field observations in Mexico’s Yucatán Peninsula.

The scientists used the data to explore a feature of Geoffroy’s spider monkey social behavior in which group members divide into small subgroups and then come together in different combinations to enhance shared knowledge.

The same subgroup may never feed together twice.

Dr Matthew Silk, an ecologist from the University of Edinburgh, said: “This is not random social mixing. This is an intelligent system for sharing insider knowledge about where the best fruit trees are in their forest.”

“By constantly changing subgroups, monkeys who are familiar with different parts of the forest can share information about where fruits are available.

“We tracked the movements of individual monkeys and mapped their main ranges, or areas that each monkey knows well. Some parts of the forest are known by several monkeys, like the most popular restaurant in a town, while others are known by only one or two monkeys, like a hidden gem.

“There is enough overlap for the monkeys to meet and exchange advice, but enough separation for each monkey to explore different parts of the forest. This maximizes the entire group’s collective coverage of the best places to forage.”

Ross Walker, a doctoral student at Heriot-Watt, developed a mathematical modeling method to analyze what monkeys gain from these relationships.

“We showed that there is a happy medium between monkeys who stick together and those who overextend,” he said.

“It’s best for individuals to explore different areas, while reconnecting often enough to share what they’ve learned.”

The team used data on a group of Geoffroy’s spider monkeys collected by experienced observers between January 2012 and December 2017.

The species, considered endangered, is also known as the Central American spider monkey and the black-handed spider monkey.

Professor Gabriel Ramos-Fernandez from the National Autonomous University of Mexico said: “We have shown that the fluid social dynamics of spider monkeys have an important consequence on their foraging success.

“By exploring their environment in a distributed manner, and then coming together to share the information gained in unique ways, the group as a whole can learn more about the forest than a single individual could alone.”