Abstract # 121:

Scheduled for Friday, June 19, 2015 10:15 AM-10:30 AM: (Cascade E) Oral Presentation


MEANDERING AND MARCHING: GROUP MOVEMENT AND INDIVIDUAL BEHAVIOUR IN BABOONS

T. R. Bonnell1,2, P. Henzi1,2 and L. Barrett1,2
1University of Lethbridge, 4401 University Dr, Department of Psychology, Lethbridge, Alberta T1K 3M4, Canada, 2Applied Behavioural Ecology and Ecosystems Research Group, UNISA, South Africa
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      Group behaviours are the outcome of individual-level interactions among group members, where individuals are thought to be predominantly reacting to, and altering, local social and ecological conditions. In heterogeneous groups, individuals of different age, rank, sex, and knowledge deal with a large array of information, but are thought largely to rely on simple rules. We measured movement patterns, capturing individual positions during daily movements (N=77 days), of a troop of baboons in De Hoop Nature Reserve, South Africa. We find that at the group level, movements largely fall within two modes of travel: marches and meanders. A K-means classification using speed and tortuosity of travel selected two classes: slow and tortuous vs. fast and straight travel events (average silhouette width = 0.61). We found differences in the spatial patterning. Associations between individuals were more frequent during meandering and showed lower measures of network centrality (e.g., closeness centrality: marching 0.36, meandering 0.10). Animals were more widely spread during marches (mean inter-individual distances: marching 6146 m, meandering = 5721 m, Cohen’s d = 0.3). To explain this movement dichotomy and the resulting spatial structures, we make use of simulation models to test between possible individual-level rules leading to observed group marches and meanders. The ability to test individual-level behavioural hypotheses in a structured way using simulations is discussed, as are opportunities for combining spatial and behavioural datasets.