GIENGER, C.M.; TRACY, C. Richard; University of Nevada-Reno: Field investigation of the ecology of the Gila monster in Nevada

The Gila monster ( Heloderma suspectum ) was studied in southern Nevada over three seasons using radio-telemetry. Activity, thermal biology, refuge selection, hibernation, and spatial habitat use were quantified. Gila monsters were most active in late May and early June, and they generally maintained lower body temperatures than do other diurnal lizard species in this part of the Mojave Desert largely by remaining in underground refugia for most of the year. Refuge site selection and activity patterns differed among seasons and they were influenced primarily by the above ground thermal environment. Gila monsters in Nevada typically travel over twice as far as Gila monsters in other parts of the species range where studies have quantified movements. Consequently, Nevada Gila monsters also had larger home ranges than those reported for Gila Monsters from southwestern Utah and western New Mexico. This result was especially salient insofar as the Nevada lizards are significantly smaller than are Gila Monsters in other parts of the species range.