Ownership influences the outcome of male-male contests in the scincid lizard, Niveoscincus microlepidotus

Male snow skinks (Niveoscincus microlepidotus) in the Tasmanianhighlands have broadly overlapping home ranges, and fight vigorously(often with substantial damage to one or both participants)upon encountering another adult male. We observed 32 male-malecontests, involving at least 49 different males, during a five-yearfield study near the summit of Mount Wellington. Bouts involvingsimilar-sized lizards typically continued for longer than boutsinvolving a greater size disparity between the combatants. Residentmales won 72% of all bouts, despite a lack of any significantdifference between residents and intruders in body sizes, relativehead sizes or body condition. Thus, prior residency of a siteappears to be the major determinant of success in male-malerivalry.