Side-blotched lizard (Uta stansburiana)

Close up of a side-blotched lizard on sand
These are the only Washington lizards with a gular fold on the throat and a dark blotch on the body behind each forelimb. (National Park Service)
Category: Reptiles
Family: Iguanidae - Iguanids
Ecosystems: Shrubsteppe
Vulnerability to climate change (More details)

Moderate

If you see this species, please share your observation using the WDFW wildlife reporting form. Providing detailed information such as a photo and exact coordinates will improve the confidence and value of this observation to WDFW species conservation and management.

This lizard's status is of concern in Washington based on the small number of populations and a distribution that is restricted to the heavily altered shrubsteppe vegetation of eastern Washington. 

Description and Range

Physical description

This is a small (maximum size 2.2 inches snout to vent length) brown or gray lizard with a mottling of black, brown and light-colored markings on the dorsal surface. They are very cryptic and blend into their surroundings. A gular fold is present on the throat. Mature males have small, light blue spots on the back and an orange tinge to the neck, sides, forelimbs and tail.

For more details, see the Washington Herp Atlas.

Ecology and life history

Side-blotched lizards are associated with arid areas that support shrubsteppe habitat. They are most common in areas with bare ground interspersed with shrubs and other vegetation (e.g., shrubland with grasses). They also occupy dry washes, rocky canyons, sand dunes and road edges.

Typically, individuals can be seen on the ground at the edge or under shrubs or other vegetation that provides cover from predators. During the heat of the day and during rainy and/or cool periods, they retreat underground or move under cover objects such as rocks and woody debris.

Habitat for these lizards is degraded by invasive plants such as cheatgrass and knapweed that grow densely between shrubs and eliminate bare ground. Excessive livestock grazing can also degrade habitat by removing too much vegetation and damaging the lower limbs of shrubs. Without the lower limbs, shrubs do not provide retreats for side-blotched lizards.

In Washington, this lizard's activity typically starts in early to mid-March and continues through October. They are ground dwelling lizards that do not climb in vegetation although they will climb on rocks and basalt outcrops. They are gregarious and interact with other lizards, often under the canopy of shrubs. They are active mid-day during spring and fall but in summer are inactive during the middle of the day when temperatures are at their maximum. They are not surface active on rainy days or cool cloudy days.

Eggs are probably laid in May and hatchlings start to appear in mid-July.

Both adults and juveniles prey on insects and arachnids.

Geographic range

In Washington, side-blotched lizards are shrubsteppe obligates that occur primarily in the driest areas of the central Columbia Basin. Most documented occurrences are in Grant and Benton Counties with additional occurrences in adjacent counties. Side-blotched lizards are gregarious and tend to be common to abundant where they occur.

This map from the Washington Herp Atlas illustrates the known distribution of side-blotched lizard in Washington as of 2016. 

Side-blotched lizard distribution map:Klickitat,Kittitas,Chelan,Yakima,Benton,Walla Walla,Franklin,Grant counties
Washington Herp Atlas (2017)

For a map of range-wide distribution and conservation status of this species, check out NatureServe Explorer.

Climate vulnerability

Sensitivity to climate change

Moderate

Side-blotched lizards appear to exhibit low reproductive sensitivity to climate, as warming temperatures (particularly warmer nights during breeding season) may increase reproductive output and subsequent survival. In Washington, side-blotched lizards are at the northern end of their geographic range, where they emerge later seasonally, have a shorter season of activity, and longer diel activity periods that are unimodal versus bimodal than at more southerly locales. Hence, warming trends linked to climate change are anticipated to result in earlier seasonal emergence, increase the length of seasonal activity, and perhaps shift unimodel diel activity periods toward bimodal ones. Further, side-blotched lizards appear to select specific temperature microhabitats, indicating behavioral thermoregulation. However, this species may exhibit some physiological sensitivity to changes in precipitation and warming winter temperatures (e.g., if warmer temperatures increase energetic demands).

Overall sensitivity of this species is somewhat higher due to its association with shrub-steppe habitats, which are sensitive to altered fire regimes and invasive weeds that degrade or eliminate habitat. Northern populations appear more dependent on grasshoppers and crickets than southern populations, but it is unclear how climate change may alter the side-blotched lizard prey base. Northern females generally lay one or two clutches of eggs during a 2 to 4 month oviposition period, whereas southern females lay one or two clutches over oviposition periods lasting as long as 5 to 6 months; hence, a shift in length of the oviposition interval may occur with increased seasonal breadth. Northern populations generally produce fewer clutches of large eggs, and produce fewer offspring each year. As northern populations appear primarily climatically challenged, climate change could reduce that challenge if the seasonal breath increases without disfavoring the available prey base, and altering energetic demands in a disfavorable way, i.e., making it more costly to maintain equivalent energy levels seasonally. High uncertainty in the pattern of response points to downgrading that confidence in the Sensitivity Rank from Moderate to Low-Moderate.

Lastly, thermal heterogeneity of microhabitats has been shown to be associated with higher rates of infection of microparasites, which result in lizards electing to bask at lower temperature outside their range of preferred temperatures. Hence, if climate change promotes thermal heterogeneity of microhabitats, it may induce a higher rate of infection of microparasites, which has uncertain, but potential negative consequences for side-blotched lizards.

Exposure to climate change

Moderate

  • Increased temperatures
  • Changes in precipitation
  • Altered fire regimes
  • Increased invasive weeds
  • Increased thermal heterogeneity

Regulations

Licenses and permits

Be advised that collection of this species is only permitted under a WDFW Scientific Collection Permit for research and educational activities.

Conservation

This species is identified as a Species of Greatest Conservation Need (SGCN) under the State Wildlife Action Plan (SWAP). SGCN-classified species include both those with and without legal protection status under the Federal or State Endangered Species programs, as well as game species with low populations. The WDFW SWAP is part of a nationwide effort by all 50 states and five U.S. territories to develop conservation action plans for fish, wildlife and their natural habitats—identifying opportunities for species' recovery before they are imperiled and more limited.

Conservation Threats and Actions Needed

  • Resource information collection needs
    • Threat: Lack of information status and distribution.
    • Action Needed: Research, survey and monitoring are needed to understand the status, distribution and habitat needs of this species.
  • Fish and wildlife habitat loss and degradation
    • Threat: Loss and degradation of suitable shrubsteppe habitat that this species relies upon in Washington.
    • Action Needed: Protect native shrubsteppe habitat from conversion and degradation due to agriculture.
    • Threat: Changes in vegetation due to livestock grazing. Livestock grazing can result in removal of too much vegetation, introduction invasive weeds, crushing of burrows and changes to the structure of shrubs as they graze under the shrubs).
    • Action Needed: Prevent livestock use and grazing practices that remove excessive amounts vegetation (change the character of the habitat), introduce invasive weeds, and change the structure of shrubs (example: cattle can damage/destroy the lower branches of shrubs as they graze under the shrubs).
  • Invasive and other problematic species
    • Threat: Changes to vegetation/habitat from non-native invasive plant species. The side-blotched lizard requires habitat with bare ground between plants. Non-native, invasive species, such as cheatgrass, create dense cover that is not suitable for this species.
    • Action Needed: Prevent land use practices that increase non-native invasive species. Where these plants already occur, find ways to remove and/or prevent expansion.

See the Climate vulnerability section for information about the threats posed by climate change to this species.

Resources

References

Dvornich, K. M., K. R. McAllister and K. B. Aubry. 1997. Amphibians and Reptiles of Washington State: Location Data and Predicted Distributions, Volume 2 in Washington State Gap Analysis - Final Report, (K.M. Cassidy, C.E. Grue, M.R. Smith and K.M. Dvornich, eds.), Washington Cooperative Fish and Wildlife Research Unit, University of Washington, Seattle, 146 pp.

Nussbaum, R. A., E. D. Brodie, Jr., and R.M. Storm. 1983. Amphibians and Reptiles of the Pacific Northwest. University of Idaho Press, Moscow, Idaho. 332 pp.

Stebbins, R. C. 1985. A Field Guide to Western Reptiles and Amphibians, 2nd Edition. The Peterson Field Guide Series. Houghton Mifflin Company, Boston. 336 pp.

Storm, R. M. and W. P. Leonard (Coordinating Editors). 1995. Reptiles of Washington and Oregon. Seattle Audubon Society The Trailside Series, Seattle, Washington. 176 pp.

WDFW publications

WDFW educational resources

Other resources