Sociality in a solitary carnivore, the wolverine

Abstract: The social organization of animal societies has important implications for several fields of biology, from managing wild populations to developing new ecological and evolutionary theory. Although much attention has been given to the formation and maintenance of societies of group living individuals, less is known about how societies of solitary individuals have been shaped and maintained. Traditionally, the evolution of social organizations in the mammalian order Carnivora has been regarded as a directional selection process from a solitary ancestry into progressively more advanced forms of sociality. In this thesis, I tested this model against an alternative model, assuming radiation from a socially flexible ancestry. I further explored sociality, resource use and dispersal of a solitary carnivore, the wolverine (Gulo gulo), in the light of these two evolutionary models. Phylogenetic reconstruction generally supported that carnivore social organizations evolved through directional selection from a solitary ancestor. However, results from captive wolverine females indicated that they might have rudimentary social tendencies, which rather support that sociality in carnivores radiated from a socially flexible ancestry. Wild wolverines in northwestern Brooks Range, Alaska, adhered to the commonly found ecological niche as a largely ungulate dependent generalist carnivore. Lack of sexual asymmetry in dispersal tendencies indicated that resource competition among wolverine females probably was high. I suggest that wolverines have latent abilities to aggregate, but that their phylogenetic legacy in terms of morphology has constrained them into an ecological niche where resource abundance and distribution generally inhibit aggregations. Due to contradictory results, I suggest further research to test evolutionary theory regarding carnivore social evolution, and particularly to explore new avenues into social evolution that better explain intra-specific variation in sociality, as well as formation and maintenance of solitary social systems.