Spider monkeys have been found to share insider knowledge about the location of the best fruit trees in their forest habitats, rather than foraging randomly, according to a new scientific study. This sophisticated information-sharing system allows the primates to maximise their collective feeding success across their environment.
Seven Years of Field Observations in Mexico
The research, which involved scientists from Heriot-Watt University, the University of Edinburgh, and the National Autonomous University of Mexico, was based on seven years of detailed field observations in Mexico's Yucatan Peninsula. The team collected data on a group of Geoffroy's spider monkeys between January 2012 and December 2017, tracking individual movements and mapping their core ranges.
Fluid Social Subgroups Enable Knowledge Exchange
Scientists discovered that spider monkeys constantly change their social subgroups, which typically consist of three or more individuals. This fluid social structure enables monkeys who know different parts of the forest to share information about where fruit is available. The same subgroup might never forage together twice, creating a dynamic system of information exchange.
Dr Matthew Silk, an ecologist from the University of Edinburgh, explained: "It isn't random social mingling; it's a clever system for sharing insider knowledge about where the best fruit trees are located across their forest home. By constantly changing their subgroups, monkeys who know different parts of the forest can share information about where fruit is available."
Optimal Balance Between Exploration and Information Sharing
The research revealed that some parts of the forest are known by multiple monkeys, while others are known by only one or two individuals. This creates enough overlap for monkeys to meet and exchange tips, but enough separation that each monkey scouts different areas of the forest.
Ross Walker, a PhD student at Heriot-Watt University who developed a novel mathematical method for the study, said: "We've shown that there's an optimal middle ground between the monkeys sticking together and spreading out too far. It's not helpful if every monkey knows exactly the same thing, and it's not helpful if no-one ever meets. It's best when individuals explore different areas, but still reconnect often enough to pool what they've learned."
Collective Intelligence in Natural Conditions
Professor Gabriel Ramos-Fernandez from the National Autonomous University of Mexico highlighted the significance of the findings: "We have shown that the fluid social dynamics of spider monkeys has an important consequence for their foraging success: by exploring their environment in a distributed fashion and then coming together to share their uniquely obtained information, the group as a whole can know the forest better than a single individual could on its own. This foraging strategy is a good example of collective intelligence in natural conditions."
The Geoffroy's spider monkey, also known as the Central American spider monkey or black-handed spider monkey, is considered an endangered species. The research team hopes to apply similar mathematical techniques to study other interactions between more than two individuals in future work.
The findings, which demonstrate how spider monkeys maximise their collective coverage of the best feeding spots through strategic information sharing, have been published in the journal npj Complexity.
