The population of striped whipsnake in Washington is low. The Washington status is based on the small number of populations. Currently only two populations are verified still existing. Threats include conversion of habitat to agriculture, degradation of native shrubsteppe habitat from irrigation water and invasive weeds, basalt mining, single home construction, and increasing vehicular traffic on roads and highways that bisect the occupied areas.
Description and Range
This is a long, slender, striped non-venomous snake. Adults range in size from 30 to 72 inches total length.
Ecology and life history
In Washington, striped whipsnakes are shrubsteppe obligates and occur primarily in the driest areas of the central Columbia Basin. The habitat of still existing populations included basalt outcrops and relatively undisturbed shrubland with grasses and a low cover of invasive cheatgrass. Striped whipsnakes use communal dens (i.e., hibernacula) in rock for winter dormancy. Clustering at hibernacula is important for surviving freezing winter temperatures and for locating mates in the spring. This species has high fidelity to hibernacula, returning to it each year to winter. Identification and protection of hibernacula sites is essential for conservation of this species.
Lizards, like the side-blotched lizard, are the predominant prey, but small mammals, snakes, young birds, and insects are also eaten.
Mammal burrows may be important for egg laying. Females lay eggs in July, and clutch sizes range from three to seven. The incubation period is 44 to 58 days.
This species is active in the daytime and may live as long as 20 years.
Striped whipsnakes reach the northern limit of their geographic range in Washington. Evidence indicates the species was never common in Washington and appears limited to the driest areas of the central Columbia Basin. All Washington occurrences are below 1,500 feet elevation.
The vast majority of lands below 1,500 feet in the Columbia Basin have been converted to agriculture or inundated by reservoirs for the Columbia Basin Irrigation Project. In addition, cheatgrass and other invasive weeds have altered the understory of shrubsteppe habitat. This is particularly problematic for this active, visual predator, as well as the ground-dwelling lizards on which it preys. Additional potential threats to striped whipsnakes include road mortalities, quarrying of basalt, construction of new transmission lines, and collecting.
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
Overall, there is a lack of information exists regarding sensitivity of the striped whipsnake to climate change. Sensitivity of this species may be influenced by its occurrence in shrub-steppe habitats, which are sensitive to changes in precipitation, invasive weeds, and altered fire regimes. Striped whipsnakes appear to show some specificity for selected den sites, at least in some areas; unfortunately, the basis of that specificity is unclear, so linking it to potential changes in climate is uncertain. Striped whipsnakes are a largely saurophagous (lizard-consuming) species that in Washington are highly dependent on side-blotched lizards for prey in the only known populations remaining in the state. Hence, climate change impacting the side-blotched lizard could directly impact this species. In northern Utah, Striped whipsnakes are locally heavily dependent on sagebrush lizards; if other populations of Striped whipsnake exist in Washington State, they could be tied to favorable sagebrush lizard locations, so climate impacts on that species could also have impacts on this snake.
Exposure to climate change
- Changes in precipitation
- Increased invasive weeds
- Altered fire regimes
Conservation Threats and Actions Needed
- Resource information collection needs
- Threat: Lack of information on status and distribution.
- Action Needed: Currently, only two extant populations are known in Washington. Inventory efforts and outreach must continue to determine if other populations occur in the state.
- Fish and wildlife habitat loss or degradation
- Threat: Loss and degradation of suitable shrubsteppe habitat that this species relies upon in Washington.
- Action Needed: Because of the apparent rarity of this species, lands where it occurs needs to be protected from agricultural conversion.
- Threat: Shrubsteppe habitat degraded by irrigation water.
- Action Needed: Protect habitat at risk for conversion to irrigated cropland that could provide suitable habitat within or between occupied areas.
- Threat: Changes in vegetation may result from unsustainable grazing through the removal of too much vegetation, the introduction of invasive weeds, crushing of mammal burrows (used by the snakes) and damage to the lower branches of shrubs from grazing under shrubs.
- Action Needed: Provide technical assistance to producers grazing within vicinity of known striped whipsnake hibernacula.
- Invasive and other problematic species
- Threat: Changes to vegetation/habitat. This species, and its lizard prey, requires habitat with bare ground between plants. Non-native, invasive species such as cheatgrass create dense ground cover.
- Action Needed: Prevent land use practices that increase non-native invasive plant species. Where these plants already occur, find ways to remove and/or prevent expansion.