Christian Willisch Univ. Neuchatel, CH Title The role of social dominance in rutting male Alpine ibex: mechanisms and consequences Abstract In large herbivores adult survival is a major factor affecting population growth. Therefore life-history strategies of animals, and consequently their allocation of resources to reproduction and survival, play an important role in the dynamics of populations. A recent study of Toïgo et al. (2007) on Alpine ibex indicates that yearly survival of adult males up to the age of 13 is with 85-99% extraordinarily high compared to males of other size dimorphic, polygynous ungulates. The authors propose that the relatively low mortality rate of adult males might be a direct consequence of an unusually conservative reproductive strategy during the rut where males keep the energy expenditures to get access to oestrous females low. In most polygynous ungulates large parts of energetic costs in rutting males are attributed to intense intra-male competitions, including displays and fights, which usually culminate concurrently with the peak of breeding activity. Therefore, the most effective way for male Alpine ibex to cut down on energy expenditures during the rut would be to minimize agonistic interactions among themselves. A possible mechanism to achieve such an energetically favourable situation could be the establishment of a strictly obligatory dominance hierarchy among males before the rut, which renders unnecessary to fight for the access to oestrous females during the rut. By presenting preliminary data from my ongoing PhD thesis on the ecology of the reproductive behaviour in Alpine ibex I would like to investigate if males are able to reduce energetically costly interactions among each other during the rut to get access to oestrous females by establishing a strictly obligatory dominance hierarchy among themselves. CV Studies in biology, University of Berne, 1997-2001 Diploma thesis on sex- and age-specific differences in the behavior of Alpine chamois during the rut, University of Berne, 2000-2001 Scientific collaborator in a project on the impact of human activities on Alpine chamois, Ethology & Nature Conservation, University of Berne, 1998-2002 Scientific collaborator in different wildlife projects on ungulates, WildARK Berne, 1999-2005 Scientific collaborator in the Swiss lynx translocation project LUNO, KORA Berne, 2001-2003 PhD thesis on the ecology of the reproductive behavior in Alpine ibex, University of Neuchâtel, 2005 to present Research interests In general my research interests are broad within the field of wildlife ecology. Particularly, I am interested in behavioural ecology and population dynamics of wild ungulates. In my PhD thesis, I plan to investigate reproductive behaviour of Alpine ibex (Capra ibex ibex), a highly dimorphic mountain ungulate. There is indication that life-history strategies of ibex differ markedly from those known in other ungulates. Therefore, a major focus of my study will be on measuring individual reproductive effort and reproductive success in male and female ibex. Furthermore by promoting our understanding of ibex ecology, the results are thought to provide reliable data necessary to optimize current management strategies for this species. Publications Willisch C.S & Ingold P. 2007. Feeding or resting? The strategy of rutting male Alpine chamois. Ethology 113: 97-104 Institution address Christian Willisch Eco-ethology Zoological Institute University of Neuchâtel Rue Emile-Argand 11 CH-2009 Neuchâtel christian.willisch@unine.ch http://www2.unine.ch/ethol/