29th Annual Meeting and Symposium of the
Desert Tortoise Council, February 20-23, 2004
Abstracts

Interactions Between Gila Monsters and Desert Tortoise

C. M. Gienger, C. Richard Tracy, Scott Sheldon, and Seth Cohen
Biological Resources Research Center, University of Nevada, Reno, Reno NV 89557

Gila monsters and desert tortoises share many of the same ecological characteristics including similar geographic distributions, low reproductive rate, and long life-span. We describe interactions among these species at a single study site in southern Nevada. Gila monsters and tortoises used many of the same refuge sites, both concurrently and at separate times. Gila monsters shared refuge sites with female tortoises disproportionately than would be expected by chance, and analysis of diet samples for Gila monsters suggest that desert tortoise eggs are an important food resource. We also describe agonistic encounters between the species, and report on nest defense behavior by a female tortoise against a Gila monster.