The population size of pygmy short-horned lizard in Washington is unknown. This species is of conservation concern because its distribution is primarily restricted to the highly altered and fragmented shrubsteppe in eastern Washington.
Description and Range
This species is a medium-sized lizard, rather toad-like in appearance with a blunt snout, round flattened body, short legs, and a short triangular tail. They are commonly called "horny toads," but they are reptiles. From snout to vent (excretory opening), the length ranges between a little over an inch to less than 3 inches. They are cryptic and their coloration tends to match the substrate. The females are significantly larger than the males.
Ecology and life history
In Washington, pygmy short-horned lizards occupy shrubsteppe habitat. They require soil conditions that allow them to burrow below the surface and substrate that is well-drained.
Adults are active mid-day during spring and fall, but in summer they are inactive during the middle of the day when temperatures are at their maximum.
A study in Washington found that "neonates" (young lizards) feed almost exclusively on ants, while ants made up about 72 percent of the adult diet.
Mating takes place soon after emergence in the spring.
Pygmy short-horned lizards reach the northern extent of their range in Washington and occur primarily in the Columbia Plateau Ecoregion. Abundance varies from site to site. The statewide trend is unknown.
The map illustrates potential range and habitat distribution of this species in Washington. For a map of worldwide distribution and other species' information, check out NatureServe Explorer.
Sensitivity to climate change
Little to no information exists regarding sensitivity of the pygmy horned lizard to climate change. Physiological sensitivity of this species may be low to moderate as it is inactive during cold weather or extended periods of heat, and it is a live-bearer. It appears to exhibit behavioral thermoregulation and burrows when inactive. Its inability to disperse long distances may increase sensitivity of this species. Overall sensitivity of this species is likely driven by its occurrence in shrub-steppe habitats, which are sensitive to altered fire regimes and invasive weeds. Though not as extremely myrmecophagous (ant-eating) as other horned lizards species, it is still preys rather heavily on ants (about three-quarters of the diet); its ability to switch to other prey should its ant prey decline as a result of climate change issues is uncertain.
Exposure to climate change
- Increased temperatures
- Altered fire regimes
- Increased invasive weeds
Conservation Threats and Actions Needed
Conservation threats to the pygmy short-horned lizard include conversion of shrubsteppe to agriculture leading to loss and degradation of suitable habitat. Conservation actions needed to address this threat include development and implementation of a strategy to ensure enough suitable shrubsteppe is maintained to support viable populations of this species. Additional threats include a lack of status and distribution information. Research, surveys, and monitoring are needed to address this issue.