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Aplodontia rufa

(Rafinesque, 1817)

Mountain Beaver

G5Secure Found in 17 roadless areas NatureServe Explorer →
G5SecureGlobal Rank
Least concernIUCN
PSESA Status
Identity
Unique IDELEMENT_GLOBAL.2.101780
Element CodeAMAFA01010
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVertebrate Animal
IUCNLeast concern
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomAnimalia
PhylumCraniata
ClassMammalia
OrderRodentia
FamilyAplodontiidae
GenusAplodontia
USESAPS
Other Common Names
Castor de montagne (FR) mountain beaver (EN) Sewellel (EN)
Concept Reference
Wilson, D. E., and D. M. Reeder (editors). 1993. Mammal species of the world: a taxonomic and geographic reference. Second edition. Smithsonian Institution Press, Washington, DC. xviii + 1206 pp. Available online at: http://www.nmnh.si.edu/msw/.
Taxonomic Comments
This is the only species in this family. Based on mitochondrial and nuclear DNA data, Piaggio et al. (2013) revised the subspecific taxonomy of A. rufa as follows. All populations north of the Columbia River belong to A. rufa olympica, which now includes the formerly recognized subspecies A. rufa ranieri and part of A. rufa rufa). Aplodontia rufa rufa occurs in Oregon (Cascades in northern Oregon, coastal region in southern Oregon) and extreme northwestern California. Aplodontia rufa pacifica occurs only in the coastal region of northwestern Oregon. The range of other nominal subspecies were not changed.
Conservation Status
Rank MethodExpertise without calculation
Review Date2016-04-04
Change Date1996-11-05
Edition Date1995-05-30
Edition AuthorsWilliams, Daniel F., and G. Hammerson
Range Extent20,000-2,500,000 square km (about 8000-1,000,000 square miles)
Number of Occurrences81 to >300
Rank Reasons
Except for two small relictual populations in California, the species is widespread in the Pacific Northwest, common, and not vulnerable to extinction.
Range Extent Comments
Pacific coast of western North America, from southwestern British Columbia south to central California. From near Merritt, British Columbia, south along the Cascade, Olympic, Coast, and Siskiyou ranges to Rio Dell, California; Mt Shasta, California, southeastward through the Sierra Nevada of eastern California and west-central Nevada; Point Arena, Mendocino County, California; and near Pt. Reyes, Marin County, California (Carraway and Verts 1993).
Occurrences Comments
Over a thousand EOs are known from throughout historic range.
Threat Impact Comments
Common and considered a pest throughout much of range in coastal areas of Northern California, Oregon, Washington and southern British Columbia. Areas inhabitated are generally not visited frequently by humans.
Ecology & Habitat

Habitat

Forested areas from near sea level to timberline. Damp ravines and shaded hillsides in coastal and montane forests with an abundance of herbaceous ground cover. Typically in riparian habitat in moist coniferous forests. Most abundant near water courses in early to mid-seral stages vegetated by a tangle of second growth tree species, shrubs and forbs, and containing debris left from earlier forests (Carraway and Verts 1993). See Beier (1989) for information on habitat in the Sierra Nevada. Prefers damp soils; digs network of tunnels along stream banks. Tunnels generally are just below the ground surface, usually on north slopes in California, on south slopes in British Columbia. Primarily fossorial but can climb trees and swims well (but not arboreal or aquatic). Mostly underground in winter. Oval nests are constructed with leaves, twigs and grasses in a chamber that may be about 2 feet below the surface of the ground.

Ecology

Usually solitary but may live in loose colonies. Population density estimates generally range from 4 to 8 per hectare, but up to 15-20/ha (see Carraway and Verts 1993). Home range of 10 adult radiotracked for 3-19 months was 0.03-0.20 ha (mean 0.12 ha); moved up to 43 m from nest (see Carraway and Verts 1993). Significant predators include coyote and bobcat.

Reproduction

Low rate of reproduction. Monoestrous. Gestation lasts 28-30 days. One litter of 2-4 (usually 2-3) altricial young born March-April, sometimes as late as early May in north. Young are weaned in about 6-8 weeks. Females sexually mature in about 2 years; yearling females may ovulate but do not breed (see Carraway and Verts 1993). A few live up to 5-6 years.
Terrestrial Habitats
Forest - ConiferForest - Mixed
Palustrine Habitats
Riparian
Other Nations (2)
United StatesN5
ProvinceRankNative
WashingtonS5Yes
CaliforniaSNRYes
NevadaS1Yes
OregonS4Yes
CanadaN4
ProvinceRankNative
British ColumbiaS3Yes
Roadless Areas (17)
California (3)
AreaForestAcres
Devil GulchSierra National Forest30,490
Lake EleanorShasta-Trinity National Forest397
Raymond PeakStanislaus National Forest3,646
Oregon (7)
AreaForestAcres
Badger CreekMt. Hood National Forest847
DoneganUmpqua National Forest5,914
Echo MountainWillamette National Forest8,098
Jackson Creek AppendageUmpqua National Forest4,673
Roaring RiverMt. Hood National Forest27,316
Smith UmpquaSiuslaw National Forest7,622
Waldo - FujiWillamette National Forest15,273
Washington (7)
AreaForestAcres
Eagle RockMt Baker-Snoqualmie National Forest34,064
Glacier Peak IMt Baker-Snoqualmie National Forest15,175
Madison CreekOlympic National Forest1,223
Mt. Baker MaMt Baker-Snoqualmie National Forest24,847
Mt. Baker Noisy - DiobsudMt Baker-Snoqualmie National Forest56,039
Mt. BaldyOlympic National Forest3,557
Silver StarGifford Pinchot National Forest7,779
References (14)
  1. American Society of Mammalogists (ASM). 2024. The Mammal Diversity Database (MDD). Online. Available: www.mammaldiversity.org
  2. Banfield, A. W. F. 1974. The mammals of Canada. University of Toronto Press, Toronto, Canada. 438 pp.
  3. Beier, P. 1989. Use of habitat by mountain beaver in the Sierra Nevada, J. Wildl. Manage. 53:649-654.
  4. Carraway, L. N., and B. J. Verts. 1993. Aplodontia rufa. Am. Soc. Mamm., Mammalian Species No. 431:1-10.
  5. Engeman, R. M., D. L. Campbell, and J. Evans. 1991. An evaluation of two activity indicators for use in mountain beaver burrow systems. Wildl. Soc. Bull. 19:413-416.
  6. Epple, G., et al. 1993. Effects of predator odors on feeding in the mountain beaver (APLODONTIA RUFA). J. Mamm. 74:715-722.
  7. Ingles, L. G. 1965. Mammals of the Pacific States. Stanford University Press, Stanford, California.
  8. Jones, J. K., Jr., R. S. Hoffman, D. W. Rice, C. Jones, R. J. Baker, and M. D. Engstrom. 1992a. Revised checklist of North American mammals north of Mexico, 1991. Occasional Papers, The Museum, Texas Tech University, 146:1-23.
  9. Lovejoy, B. P., and H. C. Black. 1979. Movements and home range of the Pacific mountain beaver <i>Aplodontia rufa pacifica</i>. American Midland Naturalist 101:393-402.
  10. Martin, P. 1971. Movements and activities of the mountain beaver (<i>Aplodontia rufa</i>). Journal of Mammalogy 52:717-723.
  11. Piaggio, A. J., B. A. Coghlan, A. E. Miscampbell, W. M. Arjo, D. B. Ransome, and C. E. Ritland. 2013. Molecular phylogeny of an ancient rodent family (Aplodontiidae). Journal of Mammalogy 94:529-543.
  12. Todd, P. A. 1992. Mountain beaver habitat use and management implications in Yosemite National Park. Natural Areas Journal 12:26-31.
  13. Wilson, D. E., and D. M. Reeder (editors). 1993. Mammal species of the world: a taxonomic and geographic reference. Second edition. Smithsonian Institution Press, Washington, DC. xviii + 1206 pp. Available online at: http://www.nmnh.si.edu/msw/.
  14. Wilson, D. E., and D. M. Reeder (editors). 2005. Mammal species of the world: a taxonomic and geographic reference. Third edition. The Johns Hopkins University Press, Baltimore. Two volumes. 2,142 pp. [As modified by ASM the Mammal Diversity Database (MDD) at https://www.mammaldiversity.org/index.html]