Spatial ecology of an apex predator, the perentie, in arid Australia

Animals are thought to use space non-randomly in relation to key resources that may change over time. Understanding these movements and the space use of wide-ranging species is particularly challenging. I studied the spatial ecology of Australia’s largest lizard, the perentie (Varanus giganteus), in the southwest Northern Territory of Australia using radio telemetry. I asked how home range size varies intraspecifically and examined the effect of individual (sex, mass and snout-vent-length) and environmental factors (month, season, mean temperature, rainfall) on the temporal movement patterns in 25 perenties over a 25-month period using minimum convex polygon and kernel density home range estimates. The perenties were highly mobile with home ranges among the largest recorded for terrestrial ectotherms. Male perenties had significantly larger home ranges and travelled longer daily distances compared to females. Home ranges for both sexes frequently overlapped spatially and were consistent across multiple years. Minimum temperature was a significant predictor for monthly variation in daily distances travelled, underscoring the importance of temperature for perentie movement. This study provides novel insight into the ecology of the perentie, an apex reptilian predator. Its extensive space use challenges our perception of the energetics and movement patterns of large predatory reptiles.