Social Networks and the Formation and Maintenance of River Otter Groups

Male social congregations (sensu Parish et al. 1997) outside of the breeding season have been documented in ungulates, whales, seals, primates, and carnivores (Ruckstuhl & Neuhaus 2000; Begg 2001; Blundell et al. 2002a,b). Several hypotheses have been proposed to explain why males form social congregations or coalitions. These include increased mating success, territorial defense, predator detection and avoidance, and cooperative foraging. For example, in elk (Cervus elaphus) and bighorn sheep (Ovis canadensis), male bachelor-groups are thought to facilitate increased predator detection and avoidance, and decreased competition with females for forage throughout the year except during the rut (Geist & Petocz 1977; Berger 1978; Lawson & Johnson 1982; Peek 1982). Red howler monkeys (Alouatta seniculus) form male coalitions in order to increase mating success and compete for reproductive females (Pope 1990). Male lions (Panthera leo) form coalitions in order to compete jointly for opportunities to join Correspondence Merav Ben-David, Department of Zoology and Physiology (3166), 1000 E. University Ave. University of Wyoming, Laramie, WY 82071, USA. E-mail: [email protected]