Figure 3. | Habitat and social factors shape individual decisions and emergent group structure during baboon collective movement

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Habitat and social factors shape individual decisions and emergent group structure during baboon collective movement

Figure 3.

Affiliation details

Princeton University, United States; Max Planck Institute for Ornithology, Germany; University of Konstanz, Germany; University of Oxford, United Kingdom; University of California, Davis, United States; Smithsonian Tropical Research Institute, Panama
Figure 3.
Download figureOpen in new tabFigure 3. The interplay between habitat and social features in shaping individual movement decisions.

We compare each real location where a baboon moved to an alternative location that it could have moved. We randomly select one of these two locations and denote it location 1, denoting the other location 2. Each plot shows the probability that location 1 was the true location actually chosen by the baboon, as a function of the difference between the numbers of other baboons that had recently (within the past 4.5 min) occupied location 1 and the number that had recently occupied location 2. (A) Across all data, the location chosen by the focal baboon is more likely to be the one recently occupied by more of its group mates. Moreover, the greater the difference between the number of baboons to have occupied each location, the stronger the effect (sigmoidal shape of curve). (B,C) Movement decisions are altered by the influence of roads. Here, data are shown from when the focal baboon started on a road (B) and when it started off a road (C), in three different cases: neither location was on a road (black line), both locations were on a road (blue line) or location 1 was on a road whereas location 2 was not (red line). (DF) Movement decisions are influenced by the direction of the sleep site in the morning (D) and evening (F), but less in the midday (E). Each colored line shows data from instances when the difference in the steps’ directedness toward the sleep site between location 1 and location 2 fell into a different bin (given in the legend), with lighter (more yellow) colors indicating a greater difference. When there is little difference (dark purple lines), the curve resembles that shown in panel A. As the difference increases, the location that is in the direction away from (in the morning) or towards (in the evening) the sleep site becomes more likely to be chosen by the baboon. Shaded regions denote 95% confidence intervals (based on Clopper-Pearson intervals). See also Appendix 1—figure 12 (other environmental influences) and Appendix 1—figure 13 (10 m steps rather than 5 m steps).