Northern Rubber Boa - Charina bottae
(see State Rank Reason below)
State Rank Reason (see State Rank above)
Species is apparently secure and not at risk of extirpation or facing significant threats in all or most of its range.
- Details on Status Ranking and Review
ScoreF - 20,000-200,000 km squared (about 8,000-80,000 square miles)
Comment192,908 square Kilometers from Natural Heritage Program range maps
ScoreU - Unknown. Long-term trend in population, range, area occupied, or number or condition of occurrences unknown
CommentNo data on trends available
ScoreU - Unknown. Short-term trend in population, range, area occupied, and number and condition of occurrences unknown.
CommentNo data on trends available
ScoreU - Unknown. The available information is not sufficient to assign degree of threat as above. (Severity, scope, and immediacy are all unknown, or mostly [two of three] unknown or not assessed [null].)
CommentUnknown. Range is poorly defined, threats to eastern populations may exist, but are unknown at this time
ScoreC - Not Intrinsically Vulnerable. Species matures quickly, reproduces frequently, and/or has high fecundity such that populations recover quickly (< 5 years or 2 generations) from decreases in abundance; or species has high dispersal capability such that extirpated populations soon become reestablished through natural recolonization (unaided by humans).
CommentNot Vulnerable. Species is long lived, births 2-8 young per year and has good connectivity within its habitat
ScoreB - Narrow. Specialist. Specific habitat(s) or other abiotic and/or biotic factors (see above) are used or required by the Element, but these key requirements are common and within the generalized range of the species within the area of interest.
CommentAssociated with mesic forests and rock outcrops
Raw Conservation Status Score
3.5 + 0 (geographic distribution) + 0 (environmental specificity) + 0 ( trend) + 0 (intrinsic vulnerability) = 3.5
This snake looks and feels like rubber, hence its name. It is a small, shiny, stout snake (12 to 28 inches) with very small eyes and a blunt tail. The scales are small and smooth, except for those on the head, which are enlarged. Dorsum of adult is plain brown to olive green, venter is cream to yellow, sometimes with dark flecks or brown, orange, or black mottling; young are pinkish to tan above, light yellow to pink below. Top of head is covered with large symmetrical plates; pupil is vertically oval. Males and some females have a spur on each side in the anal region. Total length of adults usually is 35 to 83 cm (Stebbins 1985).
The Eastern Racer is much more active, has larger eyes, and has a thin, tapered tail.
Western Hemisphere Range
Observations in Montana Natural Heritage Program Database
Number of Observations:
(Click on the following maps and charts to see full sized version)
Map Help and Descriptions
(Observations spanning multiple months or years are excluded from time charts)
Rubber Boas are secretive, slow-moving, docile snakes, usually found under logs and rocks in either moist or dry forest habitats. They are primarily nocturnal, but occasionally may be observed sunning on roads, trails, or in open areas. They feed primarily on small mice but also take shrews, salamanders, snakes, and lizards. Two to eight young are born alive in late summer or early fall. In Mission Mountains, were usually found in large talus slides or under logs/rocks near slides (Brunson and Demaree 1951) or in leaf-litter in deep shaded Douglas-fir/cedar forest (Franz 1971). Often found in areas with many flat rocks and near water (Baxter and Stone 1980).
Ecological Systems Associated with this Species
- Details on Creation and Suggested Uses and Limitations
How Associations Were Made
We associated the use and habitat quality (common or occasional) of each of the 82 ecological systems mapped in Montana for
vertebrate animal species that regularly breed, overwinter, or migrate through the state by:
- Using personal observations and reviewing literature that summarize the breeding, overwintering, or migratory habitat requirements of each species (Dobkin 1992, Hart et al. 1998, Hutto and Young 1999, Maxell 2000, Foresman 2012, Adams 2003, and Werner et al. 2004);
- Evaluating structural characteristics and distribution of each ecological system relative to the species' range and habitat requirements;
- Examining the observation records for each species in the state-wide point observation database associated with each ecological system;
- Calculating the percentage of observations associated with each ecological system relative to the percent of Montana covered by each ecological system to get a measure of "observations versus availability of habitat".
Species that breed in Montana were only evaluated for breeding habitat use, species that only overwinter in Montana were only evaluated for overwintering habitat use, and species that only migrate through Montana were only evaluated for migratory habitat use.
In general, species were listed as associated with an ecological system if structural characteristics of used habitat documented in the literature were present in the ecological system or large numbers of point observations were associated with the ecological system.
However, species were not listed as associated with an ecological system if there was no support in the literature for use of structural characteristics in an ecological system, even if
point observations were associated with that system.
Common versus occasional association with an ecological system was assigned based on the degree to which the structural characteristics of an ecological system matched the preferred structural habitat characteristics for each species as represented in scientific literature.
The percentage of observations associated with each ecological system relative to the percent of Montana covered by each ecological system was also used to guide assignment of common versus occasional association.
If you have any questions or comments on species associations with ecological systems, please contact the Montana Natural Heritage Program's Senior Zoologist.
Suggested Uses and Limitations
Species associations with ecological systems should be used to generate potential lists of species that may occupy broader landscapes for the purposes of landscape-level planning.
These potential lists of species should not be used in place of documented occurrences of species (this information can be requested at: mtnhp.org/requests
) or systematic surveys for species and evaluations of habitat at a local site level by trained biologists.
Users of this information should be aware that the land cover data used to generate species associations is based on imagery from the late 1990s and early 2000s and was only intended to be used at broader landscape scales.
Land cover mapping accuracy is particularly problematic when the systems occur as small patches or where the land cover types have been altered over the past decade.
Thus, particular caution should be used when using the associations in assessments of smaller areas (e.g., evaluations of public land survey sections).
Finally, although a species may be associated with a particular ecological system within its known geographic range, portions of that ecological system may occur outside of the species' known geographic range.
- Adams, R.A. 2003. Bats of the Rocky Mountain West; natural history, ecology, and conservation. Boulder, CO: University Press of Colorado. 289 p.
- Dobkin, D. S. 1992. Neotropical migrant land birds in the Northern Rockies and Great Plains. USDA Forest Service, Northern Region. Publication No. R1-93-34. Missoula, MT.
- Foresman, K.R. 2012. Mammals of Montana. Second edition. Mountain Press Publishing, Missoula, Montana. 429 pp.
- Hart, M.M., W.A. Williams, P.C. Thornton, K.P. McLaughlin, C.M. Tobalske, B.A. Maxell, D.P. Hendricks, C.R. Peterson, and R.L. Redmond. 1998. Montana atlas of terrestrial vertebrates. Montana Cooperative Wildlife Research Unit, University of Montana, Missoula, MT. 1302 p.
- Hutto, R.L. and J.S. Young. 1999. Habitat relationships of landbirds in the Northern Region, USDA Forest Service, Rocky Mountain Research Station RMRS-GTR-32. 72 p.
- Maxell, B.A. 2000. Management of Montana's amphibians: a review of factors that may present a risk to population viability and accounts on the identification, distribution, taxonomy, habitat use, natural history, and the status and conservation of individual species. Report to U.S. Forest Service Region 1. Missoula, MT: Wildlife Biology Program, University of Montana. 161 p.
- Werner, J.K., B.A. Maxell, P. Hendricks, and D. Flath. 2004. Amphibians and reptiles of Montana. Missoula, MT: Mountain Press Publishing Company. 262 p.
- Commonly Associated with these Ecological Systems
Forest and Woodland Systems
Recently Disturbed or Modified
Shrubland, Steppe and Savanna Systems
Sparse and Barren Systems
Wetland and Riparian Systems
- Occasionally Associated with these Ecological Systems
Forest and Woodland Systems
Human Land Use
Recently Disturbed or Modified
Shrubland, Steppe and Savanna Systems
Sparse and Barren Systems
Wetland and Riparian Systems
One found dead on road contained a Microtus longicaudus (Brunson and Demaree 1951).
In western OR, found in variety of habitats except areas with regular grazing or cultivation, or areas periodically flooded (Hoyer 1974). Largely crepuscular or nocturnal (Stebbins 1954).
Probably mate later inland. In eastern OR, mate late April to early May. Young usually born in September (Nussbaum et al. 1983). Reported parturition dates are September (UT) and September 20 to 21 (WA). Average number of young is 4.4 (2 to 8) (Fitch and Fleet 1970).
- Literature Cited AboveLegend: View Online Publication
- Baxter, G.T. and M.D. Stone. 1980. Amphibians and reptiles of Wyoming. Wyoming Game & Fish Department, Cheyenne. 137 pp.
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- Fitch, H.S. and R.R. Fleet. 1970. Natural history of the milk snake (Lampropeltis triangulum) in northeastern Kansas. Herpetologica 26: 387-396.
- Franz, R. 1971. Notes on the distribution and ecology of the herpetofauna of northwestern Montana. Bulletin of the Maryland Herpetological Society 7: 1-10.
- Hoyer, R.F. 1974. Description of a rubber boa (Charina bottae) population from western Oregon. Herpetologica 30(3): 275-283.
- Nussbaum, R.A., E.D. Brodie, Jr. and R.M. Storm. 1983. Amphibians and reptiles of the Pacific Northwest. University of Idaho Press. Moscow, ID. 332 pp.
- Stebbins, R.C. 1954. Amphibians and reptiles of western North America. McGraw-Hill, New York. Xxii + 528 pp.
- Stebbins, R.C. 1985. A field guide to western reptiles and amphibians. Houghton Mifflin Company, Boston. 336 pp.
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?
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- Additional Sources of Information Related to "Reptiles"