July 22 (UPI) -- When foraging for food, spider monkey groups utilize collective computation to organize the hunt for fruit-filled trees.
Mexico's wild spider monkeys form fission-fusion societies -- when it's time to forage for food, the larger society splits into smaller groups -- according to a study published this week in the journal Frontiers in Robotics and AI.
When forming teams, there are no captains or coaches to direct the monkeys into specific groups. The monkeys are on their own to organize, and their individual decisions yield a range of foraging team sizes.
To form ideal sized teams for finding fruit in the forest, the spider monkeys use what's called collective computing, researchers say.
"By forming these subgroups -- constantly coming together and splitting -- the spider monkeys develop a more thorough knowledge of their environment," lead study author Gabriel Ramos-Fernandez said in a news release.
"They seem to be pooling information about resources, so that as a group they know their environment better than any individual does on its own," said Ramos-Fernandez, a researcher at the National Autonomous University of Mexico.
To better understand this process, researchers in Mexico spent two years observing the interactions of 47 monkeys for five hours per day. Researchers found the monkeys typically form subgroups ranging in sizes of 2 to 17 monkeys. Subgroups typically remained intact for one to two hours.
"We noted who was where, and with whom, at any given time," Ramos-Fernandez said.
With the help of scientists at the Santa Fe Institute, in New Mexico, Ramos-Fernandez and his colleagues used inductive game theory to codify the decision making process for each monkey. The scientists were able to identify rules that dictate whether a monkey decides to join or leave a group.
Instead of assuming the strategies that govern monkey decision making, as is done using traditional game theory, researchers amassed a list of possible decision making rules, and let the monkey's behavior reveal which rules apply and when.
"This kind of methodology is useful for studying optimal foraging because it requires no a priori assumptions about benefits and costs," said Ramos-Fernandez.
Their analysis showed a monkey's decision to stay or leave is heavily influenced by the decisions of the other moneys in a team or subgroup. Effectively, each monkey polls the group to get a sense for the proper team size.
Researchers found this decision making process produces a diversity of team sizes, a range that works well for finding fruit trees in the forest.
Ramos-Fernandez and his colleagues suggest similar methodology could be used to study the formation and organization of flocks of birds, schools of fish or financial markets.