While baboons definitely have a hierarchical social structure, it turns out the top members of a group don't call the shots when it comes to hitting the road. For that, the group, and not the individual, calls the shots.
Those findings come thanks to research performed by a team of scientists from Princeton University and the University of California, Davis, whose work has just been published in the journal Science.
The researchers placed GPS trackers on individual baboons in a group and then logged their movement across the savannah in Kenya, to discern how the animals' collective decisions about group direction came about.
"What's fascinating about baboons is that they do absolutely everything together and therefore always have to reach a compromise," said Iain Couzin, of Princeton University and the Max Planck Institute for Ornithology, in a press release.
The baboons' movements indeed suggested a democratic approach to the big decision of where to go next. The process kicks off when some individual baboons elect together to take a new route by moving away from the larger group. The greater the number of such traiblazers, the team noted, the greater the chance that the rest of the group would follow.
"The alpha animal did not, therefore, decide dictatorially, but the group instead makes democratic decisions," said Couzin.
And what happens if there is not a bold push in a single new direction? The researchers said the baboons solved directional disagreements by compromising on a middle route, if the possible paths were not too far apart in angle. If the possible directions were far apart, though, they chose one or the other.
Evaluating the GPS data was no easy task, taking the scientists several years to conclude. "It was difficult for us to understand when the baboons were trying to influence one another and when not," Couzin explained. So difficult that Couzin flew to Kenya to perform supporting field observations of the animals. That journey paid off, as the field work and movement data ended up playing well together.
"We would never have been able to develop our algorithm without these field studies, and without the algorithm we could never have understood how the decision-making process works," Couzin said.
Next up, the team wants to analyze what role terrain may play in the baboons' movement decisions. To that end, the scientists are using a drone to make aerial 3-D maps. "We believe that information about the environment could provide us with very different insights into the animals' social behavior."