Behaviour 2019
"Female reindeer do not spatially associate based on relatedness, but socialize less as they grow older"
Julienne T. Bonoan1, Robert B. Weladji1, Guillaume Body2, Øystein Holand3, Knut H. Røed4. 1Concordia University, Montreal, Quebec, Canada; 2Office National de la Chasse et de la Faune Sauvage, Paris, Île-de-France, France; 3Norwegian University of Life Sciences, Ås, Follo, Norway; 4Norwegian School of Veterinary Science, Ås, Follo, Norway

Understanding the drivers of how animals socialize and associate with each other in a population can provide insights into the ecology, biology, and behaviour of its members. The effect of age and genetic relatedness on the social patterns of an animal population exhibiting fission-fusion group dynamics was assessed using a semi-domestic herd of female reindeer (Rangifer tarandus), situated in Kaamanen, Finland. Analyses were done using GPS-telemetry and Social Network Analysis (SNA) in 2009 and 2011 during the breeding season (or rut). We found that females had distinct communities and associated non-randomly in both years; however, genetic relatedness and age were not significant predictors of community structure. Although age did not influence community structure, age affected association levels, where females associated with each other significantly less after the age of 7. Overall, our results provided insights into the social patterns of a population exhibiting fission-fusion group dynamics, in which females do not associate based on relatedness and age but socialize less as they grow older during the rut.