Common sharp-tailed snake (Contia tenuis)

Close up of a coiled common sharp-tailed snake on the ground
This is the only snake in Washington with a spine at the tip of the tail and alternating bands of white and black on the ventral (underside) scales. (Don Loarie, Creative Commons)
Category: Reptiles
Family: Colubridae - Colubrids
Ecosystems: Shrubsteppe Riparian areas
State status: Candidate
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 snake is of conservation concern in Washington based on the small number of documented populations, patchy distribution, and lack of information.

Common sharp-tailed snakes are rarely encountered and little studied. Nothing of what is known about this species in Washington explains their apparent rarity, but there is also no evidence that they are more common based on the small number of observations reported to WDFW and  iNaturalist.

Description and Range

Physical description

This is a diminutive, semi-fossorial species that is usually less than 12 inches long, and rarely exceeds 16 inches. It is reddish brown above with with indistinct reddish dorsolateral stripes. It has a distinct ventral pattern of alternative black and cream colored bands. It has a short tail that terminates with a small spike-like scale and is the only snake in Washington with this trait (the tails starts after the vent opening). The tail spine is occasionally absent due to injury. Young snakes are redder in coloration and have more distinct lines down the sides than adult snakes.

These snakes have relatively long, re-curved teeth, that are thought to be a specialization for grasping and holding slugs and other soft-bodied invertebrates that are the primary prey of this snake.

See the Washington Herp Atlas for more information about this species.  

Ecology and life history

In the Pacific Northwest, the common sharp-tailed snake are found on the edges of coniferous or open hardwood forest. In Washington, the snakes have been found in: 1) forest openings dominated by Garry Oak often with rock accumulations; 2) riparian/river floodplain with deciduous trees, shrubs and accumulations of decaying down woody logs; 3) shrub-steppe uplands with riparian areas that support deciduous trees and have accumulations of woody debris and rocks.

The snakes are usually found under cover objects in moist rotting logs or stumps, talus, or other accumulations. They are often near streams or in other damp habitats. Small canopy gaps with rocky substrates, particularly those that are south-facing, may be important for thermoregulation, egg development and growth of young. Snakes show evidence of site tenacity, with some snakes found repeatedly under the same cover objects.

Most surface activity occurs when the surface is cool and moist in the spring and fall although observations have been made in most months of the year.

Breeding takes place in April or May. Eggs are laid in late June or July and hatching occurs in the fall. Activity is confined to relatively small areas. The greatest distance moved by two study snakes in Canada was 128 and 305 feet. Many biologists have noted that they find small aggregations of these snakes, for instance, inside of a decaying log.

Geographic range

Common sharp-tailed snakes occur from British Columbia, Canada into southern California. In Washington, common sharp-tailed snakes are known from thirteen disjunct areas. West of the Cascade Mountain crest, there is an historical record for Pierce County and two recently discovered sites on Orcas and San Juan Islands. East of the Cascade Crest observations are from Chelan, Kittitas, Yakima, Klickitat and Skamania Counties. Almost nothing is known about abundance and some occurrences are based on a single observation.

This map from the Washington Herp Atlas illustrates the known distribution of common sharp-tailed snake in Washington as of 2016. 

2016 common sharp-tailed snake state distribution map: San Juan, Skamania, Klickitat, Chelan, Kittitas, Yakima 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

Overall, a lack of information exists regarding sensitivity of the sharp-tailed snake to climate change. Sensitivity of this species may be influenced by its occurrence along edges of coniferous or open hardwood forest, which are sensitive to warming temperatures, moisture stress, and changing fire patterns. This species may also exhibit some sensitivity to warmer temperatures and changes in precipitation as they are often associated with moist habitats.  This species is often found in and under decaying downed woody debris.  Increased fire frequency and intensity could result in loss of this microhabitat type.  This species is also an egg-layer that could be influenced by soil moisture patterns at oviposition sites; but lack of data on typical oviposition sites makes any prediction of potential changes highly uncertain. Furthermore, this species is a mollusc and soft-bodied invertebrate specialist, so its typical prey base has a high probability of being influenced by soil moisture levels; however, it ability to switch to alternative prey is unknown, so the degree of influence on its prey base is uncertain. Lastly, the species appears to be near-surface active only during periods of higher moisture levels; whether this is directly related to its prey base or its intrinsic moisture requirement or both is unclear. Regardless, the influence of shortened or lengthened periods of surface activity resulting from climate change is uncertain. 
 

Confidence: Low

Exposure to climate change

Moderate

  • Increased temperatures
  • Changes in precipitation
  • Altered fire regimes
  • Altered prey base as a consequence on one or more of the above
Confidence: Low

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.
This species is identified as a Priority Species under WDFW's Priority Habitat and Species Program. Priority species require protective measures for their survival due to their population status, sensitivity to habitat alteration, and/or recreational, commercial, or tribal importance. The PHS program is the agency's main means of sharing fish and wildlife information with local governments, landowners, and others who use it to protect priority habitats for land use planning.

Conservation Threats and Actions Needed

  • Resource information collection needs
    • Threat: Lack of information on 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 or degradation
    • Threat: Loss of prairie and oak habitat. With observations on San Juan Island, no extant occurrences are known from western Washington. This species is thought to have been associated with prairie habitat in western Washington and most of this habitat type was converted to agriculture or developed for housing.
    • Action Needed: Inventory and outreach to determine if this small, secretive snake still occurs in areas of western Washington other than the San Juan Islands.
    • Threat: Loss of suitable habitat due to harvest of trees. Little is known about threats to this species from habitat alteration but forestry practices likely impact local populations because the loss of canopy changes the moisture regime, increases temperature and removes down woody debris and leaf litter.
    • Action Needed: Identify where this species occurs and work with landowners to conserve habitat features important for the persistence of this species, such as downed woody debris and rock features.

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

Living with wildlife

Snakes are among the most misunderstood of all animals. Of the dozen or so species of snakes found in Washington, only the western rattlesnake is capable of inflicting a venomous bite, which it seldom does. All snakes are an important part of the natural food chain, eating a variety of prey—from mice and birds to frogs and insects.

Observe snakes, like all wild animals, from a respectful distance. Learn more about living with snakes.

 

Resources

References

Cook, S. F. 1960. On the occurrence and life history of Contia tenuis. Herpetologica 16: 163-173.

Hallock, L. 2009. Conservation Assessment for the Sharp-tailed Snake (Contia tenuis) In Washington and Oregon. Unpublished Report. Washington Natural Heritage Program, Department of Natural Resources, Olympia. Submitted to the Interagency Special Status/Sensitive Species Program, Washington and Oregon. USDS Forest Service and Bureau of Land Management.

Leonard, W. P., D. M. Darda, and K. R. McAllister. 1996. Aggregations of Sharptail Snake (Contia tenuis) on the east slope of the Cascade Range in Washington State. Northwestern Naturalist 77: 47-49.

Leonard, W. P. and M. A. Leonard. 1998. Occurrence of the Sharptail Snake (Contia tenuis) at Trout Lake, Klickitat County, Washington. Northwestern Naturalist 79: 75-76.

Leonard, W.P. and K. Ovaska. 1998. Contia, C. tenuis. Catalogue of American Amphibians and Reptiles: 677.1-677.7.

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. ,

Ovaska, K. E. and C. Engelstoft. 2008. Conservation of the Sharp-tailed Snake (Contia tenuis) in urban areas in the Gulf Islands, British Columbia, Canada. In Mitchell, J., R. Jung Brown and B. Bartholomew Editors. 2008. Urban Herpetology. Herpetological Conservation 3:557-564. Society for the Study of Amphibians and Reptiles. Salt Lake City.

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.

Zweifel, R.G. 1954. Adaptation to feeding in the snake Contia tenuis. Copeia 1954(4): 299-300.

Personal communications

William (Bill) Leonard, Washington Department of Transportation, Olympia, Washington.
Robert Weaver, Graduate Student, Central Washington University, Ellensburg, Washington.

WDFW publications

PHS Program

WDFW educational resources

Other resources