Above: Gila monster (Heloderma suspectum) at the American International Rattlesnake Museum. By I, Blueag9, CC BY-SA 3.0, Wikimedia Commons.
Gila monsters, the only venomous lizard native to Nevada, face escalating conservation challenges in the state amid limited habitat protection and pressures from climate change, University of Nevada, Reno alumnus Christopher Gienger told attendees at the UNR Ecology, Evolution & Conservation Biology Colloquium on Feb. 26.
Gienger, now a professor at Austin Peay State University in Tennessee, said Nevada represents the northern edge of the species’ distribution and remains one of the least studied areas for the reptile. Prior to 2000, only 12 verified Gila monsters had been documented in the state. The species is listed as near threatened in Nevada, and concerns about populations near Las Vegas prompted a collaborative research effort with University of Nevada, Reno professor Kenneth Nussear and U.S. Geological Survey scientist Amy Vandergast to examine habitat suitability and genetic connectivity.
The Nevada study tracked 41 Gila monsters using radio telemetry, with some individuals monitored for up to six years, Gienger said. Movement data were used to develop spatially explicit habitat suitability and connectivity models. Genetic material collected from captured animals was analyzed to evaluate population structure and connectivity across southern Nevada and Utah. The analysis identified moderate population clustering, suggesting that manmade barriers could limit gene flow between groups.
In a separate line of research, Gienger’s lab used species distribution models to examine habitat protection across the reptile’s broader range. That analysis found that only about 7% of suitable Gila monster habitat in the United States falls within protected lands. In Mexico, which contains roughly 58% of the species’ total range, that figure drops to about 3%, he said. Habitat fragmentation from roads and development may further isolate populations across the Southwest.
Gila monsters show strong site fidelity, meaning relocation efforts are unlikely to succeed, Gienger said. Individuals moved to new areas attempt to return to their original home ranges and are often killed crossing roads, resulting in what he described as “a 100% mortality rate.” Habitat modeling indicates the species prefers mid-elevation mountain ranges while avoiding valley bottoms and higher elevations, a pattern that could complicate future range shifts as temperatures rise in Nevada’s changing deserts.
Gila monsters spend roughly 95% of their time in underground burrows and move infrequently, traits that make them particularly vulnerable to habitat disturbance and fragmentation.
With much of the species’ suitable habitat outside protected areas, long-term conservation will depend on how land managers address development and climate pressures across the region. As temperatures rise and desert ecosystems shift, researchers say understanding where Gila monsters persist and how populations remain connected will be critical to preventing further decline.
Alanna Garcia is a master’s student in the Natural Resources and Environmental Science Department at the University of Nevada, Reno. Her work focuses on black bear ecology and movement in Nevada. She wrote this story for the Hitchcock Project’s Science & New Media course during spring 2026 in the Reynolds School of Journalism.
