Columbia Oregonian (snail) (Cryptomastix hendersoni)

Close up of three Columbia Oregonian snails on a white sheet of graph paper
Three Columbia Oregonian snails. (J. S. Applegarth)
Category: Molluscs
Ecosystems: Riparian areas
State status: Candidate
Vulnerability to climate change (More details)


If you see this species, please share your observation using the WDFW wildlife reporting tool or email us at Be sure to include a photo of the species for verification and location (latitude/longitude coordinates) of your observation. 

The Columbia Oregonian's population size is critical and has a declining trend. These snails are in the Family Polygyridae. Snails in this family are of conservation concern because they have specialized habitat requirements. Snails do not readily disperse and populations are isolated. They are vulnerable to alteration of their habitat.

Description and Range

Physical description

The Columbia Oregonian snail is in the Polygyridae Family, which is a large and diverse family of roughly 294 described snail species in North America. The Cryptomastix species are medium to moderately large Pacific Northwest endemics.

Ecology and life history

Life history of the terrestrial Polygyrids, like the Columbia Oregonian, may resemble that described for the Oregon Forestsnail (Allogona townsendiana). This species is most active during the wet spring months when mating occurs. Adults lay eggs in new or existing flask-shaped nesting holes, or sometimes in pre-existing depressions in soil, moss, and under coarse woody debris, or at the base of vegetation. Juvenile snails hatch approximately eight to nine weeks after oviposition, and disperse from the nest site within hours of hatching. 

The Columbia Oregonian occurs at seeps and spring-fed streams and in associated talus in the semi-arid eastern portion of the Columbia River Gorge. Inhabits margins of low to mid-elevation seeps, and spring-fed streams in an otherwise arid landscape. Typically found among moist talus, leaf litter and shrubs, or under logs and other debris.

Polygyrids are generally herbivorous and fungivorous snails. The Columbia Oregonian consume herbaceous plants in captivity, and may also consume algae on wet surfaces and decaying remains of herbaceous plants.

Geographic range

The Columbia Oregonian snail is known from 13 locations at the east end of the Columbia Gorge along both sides of the river from The Dalles to Rufus, Wasco and Sherman Counties in Oregon; this includes only four small sites in Klickitat County, Washington. Most locations are isolated from one another by the arid surrounding landscape. Originally also occurred in Skamania County, and in The Dalles, Oregon, but these sites were lost to by development. Specimens that may be this species suggest its range may extend north into Yakima County, and east along the Columbia and Snake Rivers and the Washington-Oregon border, in Umatilla and Wallowa Counties, Oregon, to Adams and Washington Counties, Idaho, but this requires confirmation.

For a map of this species' world-wide location and conservation status, check out NatureServe Explorer.

Climate vulnerability

Sensitivity to climate change


There is limited information on the sensitivity of the Columbia Oregonian snail to climate change. This species is found in low-elevation seeps and streams of the Columbia River Gorge as well as mid-elevation upland habitats (782-1000 meters) in hemlock forests. In each of these locations, the snails find cover provided by herbaceous riparian vegetation in aquatic environments and large woody debris in forests. Loss of these refugia would likely alter the temperature and moisture regimes – low temperature and moderate to high humidity – upon which this species relies.

Confidence: Low

Exposure to climate change


  • Increased temperatures
  • Reduced soil moisture and/or drought
  • Altered fire regimes
Confidence: Low


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

  • Fish and wildlife habitat loss or degradation
    • Threat: Loss of perennial flow due to diversions
    • Action Needed: Taxonomic clarification for additional taxa; delineate occupied sites
    • Threat: Habitat loss to development
    • Action Needed: Delineate and protect sites

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