Prey Preferences and Body Mass Most Influence Movement Behavior and Home Range Area of Komodo Dragons

Abstract

Lizards, as predators, can use different prey foraging strategies that are expected to influence daily movement behavior and home range use. Variation in lizard movement behavior can be achieved via frequency changes in movement step lengths and turning angles that can facilitate distinctive prey-searching and foraging strategies. Komodo Dragons (Varanus komodoensis) exhibit a distinct dietary transition at ∼18 kg, where lizards switch from consuming small-bodied and abundant prey species to highly dispersed adult ungulate prey. Our study examined competing models for the relative effects of ontogenetic dietary shift, body mass, sex, time of day, and arboreal habitat use on Komodo Dragon movement behavior (i.e., the proportional use of Lévy flight movement steps) and home range area (i.e., 50 and 95% utilization distributions). Model ranking indicated that two models incorporating the proportion of adult ungulates and body mass best explained the increased use of Lévy flight movement behavior of Komodo Dragons. Body mass also best explained the increase in the 50 and 95% utilization distribution Kernel home range areas. However, the slope of this relationship was less steep than that predicted by metabolic scaling theory and suggested that attributes specific to Komodo Dragons, or their environment, may attenuate their spatial requirements. This study demonstrates that because of distinct shifts in diet and other activities associated with large body size, Komodo Dragons alter movement behavior and increase their home range area to optimize environmental resource use.