Scientific name: Sceloporus graciosus graciosus
- Only lizard in Yellowstone.
- Maximum size of five inches from snout to the tip of the tail; males have longer tails and may grow slightly larger than females.
- Gray or light brown with darker brown stripes on the back set inside lighter stripes on the sides, running the length of the body; stripes not always prominent and may appear as a pattern of checks down the back; underside usually cream or white.
- Males have bright blue patches on the belly and on each side, with blue mottling on the throat.
- Usually found below 6,000 feet elevation, but in Yellowstone it can live up to 8,300 feet.
- Populations living in thermally influenced areas are possibly isolated from others.
- Most common along the lower portions of the Yellowstone River near Gardiner, Montana and upstream to the mouth of Bear Creek; also occurs in Norris Geyser Basin, Shoshone and Heart Lake geyser basins, and other hydrothermal areas.
- Comes out of hibernation about mid-May and is active through mid-September.
- Diurnal, generally observed during warm, sunny weather in dry, rocky habitats.
- During the breeding season, males do push-ups on elevated perches to display their bright blue side patches to warn off other males.
- Feeds on various insects and arthropods.
- Eaten by bullsnakes, wandering garter snakes, rattlesnakes, and some birds.
- May shed tail when threatened or grabbed.