Dynamic of social interactions: analysis and modeling from movement in several large mammal species

Mammals and birds display a large diversity of social organisations. The evolutionary and ecological processes that shape them have been partly explained but a lot of questions remain. Particularly, the temporal and spatial flexibility in social interactions in species that display fission-fusion dynamics. Ungulates are amongst those species where social groups coalesce and split dynamically in sub-groups according to environmental constraints. However, whether the social associations are randomly made or not have been poorly studied. On a large spatio-temporal scale, it could shape the home-range of individuals and their overlap accordingly to the social bond. We used a location data to study the dyadic association dynamics and their relation with the spatial structure of the population of four ungulate species. We analysed the interaction between dyadic contact, home-range overlap and distance. We then investigated if movement prior and anterior contact could indicate that individuals are willing to modify their displacement for social purpose. We found that the four species were discriminated by the metrics accordingly to their sociality and ecological constraints. We found that that the solitary species, roe deer, displayed low dyadic overlap and contact rates. The gregarious species showed high rates, in mouflon with close individuals; and in the chamois and ibex with individuals further away, suggesting a looser spatial segregation between groups than in mouflon. We did not highlight different patterns of flee or attraction effect before contact between species though. Our study is a first step in the understanding of the link between sociality and movement, which has implication in many aspects of animal ecology.