caa a22 4500 60546264X CHVBK 20210128100249.0 cr unu---uuuuu 210128e20150601xx s 000 0 eng 10.1007/s10211-014-0190-8 doi (NATIONALLICENCE)springer-10.1007/s10211-014-0190-8 Fission-fusion group dynamics in reindeer reveal an increase of cohesiveness at the beginning of the peak rut [Elektronische Daten] [Guillaume Body, Robert Weladji, Øystein Holand, Mauri Nieminen] Knowledge of the processes of group formation is important to understand the evolution of animal societies. Ungulates typically aggregate during the breeding season. According to the self-organization theory, proximal processes such as mating tactics should explain variation in average group size through their influences on group dynamics. Here, we tested whether variation of the fusion rate or fission rate led to an increase of average group size at the beginning of the peak rut. We followed the movement of marked animals within an enclosed herd of reindeer Rangifer tarandus during two breeding seasons (2009 and 2011). We used synchronized GPS collars that fixed the animals' position every hour (2009) and every 15min (2011). Group dynamics occurred in three steps as follows: (1) a continuous aggregation of groups, (2) a continuous departure of single females from these groups, and (3) the aggregation of these solitary females to form new groups. We attributed the increase in average group size mainly to a decrease in the number of groups due to a decrease in the group and individual splitting propensities, rather than to an increase of their merging propensities. A decrease in the splitting propensity at the beginning of the peak rut may be due to males herding females, female mate choice, or female harassment avoidance. Further research on fission-fusion group dynamics should calculate merging and splitting propensities by controlling for variables such as group size, group density, or habitat characteristics. Springer-Verlag Berlin Heidelberg and ISPA, 2014 Caribou nationallicence Global positioning system nationallicence Harem nationallicence Mating nationallicence Sexual selection nationallicence Sociality nationallicence Body Guillaume Department of Biology, Concordia University, 7141 Sherbrooke Street West, H4B 1R6, Montreal, QC, Canada aut Weladji Robert Department of Biology, Concordia University, 7141 Sherbrooke Street West, H4B 1R6, Montreal, QC, Canada aut Holand Øystein Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, P.O. Box 5003, N-1432, Aas, Norway aut Nieminen Mauri Finnish Game and Fisheries Research Institute, Reindeer Research Station, 99910, Kaamanen, Finland aut acta ethologica Springer Berlin Heidelberg 18/2(2015-06-01), 101-110 0873-9749 18:2<101 2015 18 10211 https://doi.org/10.1007/s10211-014-0190-8 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10211-014-0190-8 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Body Guillaume Department of Biology, Concordia University, 7141 Sherbrooke Street West, H4B 1R6, Montreal, QC, Canada aut NATIONALLICENCE 700 1- Weladji Robert Department of Biology, Concordia University, 7141 Sherbrooke Street West, H4B 1R6, Montreal, QC, Canada aut NATIONALLICENCE 700 1- Holand Øystein Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, P.O. Box 5003, N-1432, Aas, Norway aut NATIONALLICENCE 700 1- Nieminen Mauri Finnish Game and Fisheries Research Institute, Reindeer Research Station, 99910, Kaamanen, Finland aut NATIONALLICENCE 773 0- acta ethologica Springer Berlin Heidelberg 18/2(2015-06-01), 101-110 0873-9749 18:2<101 2015 18 10211