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Montana Animal Field Guide

Montana Field Guides

Long-eared Myotis - Myotis evotis

Global Rank: G5
State Rank: S4

Agency Status


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General Description
Ears are black and the longest of any other North American bat in the genus Myotis; > 0.84 inches (>21 millimeters). When bent forward, ears extend > 5 millimeters beyond the tip of the nose. Wingspan of 10-12 inches (25-30 centimeters) and weighs 0.2-0.3 inches (5-8 grams). Coat color is dull brown to straw-colored with individual hairs black at the base (Adams 2003).

Species Range
Montana Range

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Western Hemisphere Range


Summary of Observations Submitted for Montana
Number of Observations: 1321

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Possibly partially migratory; few winter records for Montana.

Occupy a wide range of rocky and forested habitats over a broad elevation gradient (Jones et al. 1973). Summer day roosts include abandoned buildings, bridges, hollow trees, stumps, under loose bark, and rock fissures. Hibernacula include caves and abandoned mines. The species has been located hibernating in a mine in riverbreaks habitat in northeastern Montana (Swenson and Shanks 1979).
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 (high, medium, or low) of each of the 82 ecological systems mapped in Montana for vertebrate animal species that regularly breed, overwinter, or migrate through the state by:
    1. 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 2001, Adams 2003, and Werner et al. 2004);
    2. Evaluating structural characteristics and distribution of each ecological system relative to the species’ range and habitat requirements;
    3. Examining the observation records for each species in the state-wide point database associated with each ecological system;
    4. 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 associated as using 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 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.  High, medium, and low habitat quality was assigned based on the degree to which the structural characteristics of an ecological system matched the preferred structural habitat characteristics for each species in the 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 assignments of habitat quality.  If you have any questions or comments on species associations with ecological systems, please contact Bryce Maxell at or (406) 444-3655.

    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: 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.

    Literature Cited
    • 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.  2001.  The wild mammals of Montana.  Special Publication No. 12.  Lawrence, KS: The American Society of Mammalogists.  278 p.
    • 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.

Food Habits
Known to primarily eat moths and beetles, but also flies, lacewings, true bugs and spiders. Stomach content analysis of 3 specimens from the Ekalaka and Long Pines Hills area of southeast Montana revealed a cicadellid, a chironomid, a small moth (Lepidoptera), a scarab beetle; a dragon fly (Agrion spp.); and a large, black bristly muscoid fly (Calliphoridae Diptera) (Jones et al. 1973).

Typically emerge 10-40 minutes after dark. Highly maneuverable; glean prey from leaves and bark or off ground.

Reproductive Characteristics
Sexes segregated in summer with females in small maternity colonies. Females have one young per year, usually born in late June or July, and return to previously used maternity roosts.

  • Literature Cited AboveLegend:   View Online Publication
    • Adams, R.A. 2003. Bats of the Rocky Mountain West: natural history, ecology and conservation. University Press of Colorado: Boulder, CO. 289 pp.
    • Jones, J.K., Jr., R.P. Lampe, C.A. Spenrath, and T.H. Kunz. 1973. Notes on the distribution and natural history of bats in southeastern Montana. Occasional papers (Texas Tech University Museum) 15:1-11.
    • Swenson, J.E. and G.F. Shanks, Jr. 1979. Noteworthy records of bats from northeastern Montana. Montana. Journal of Mammalogy 60:650-652
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Albers, Mark., 1995, Draft Biological Assessment: Tongue River Basin Project. May 1995. In Tongue River Basin Project Draft Environmental Impact Statement. Appendix B. June 1995.
    • Butts, T. W. 1993. Azure Cave bat surveys, Little Rocky Mountains, Montana, September 1992 and March 1993. Unpublished report for Zortman Mining, Inc. 13 pp.
    • Chruszcz, B. J., and R. M. R. Barclay. 2003. Prolonged foraging bouts of a solitary gleaning/hawking bat, Myotis evotis. Canadian Journal of Zoology 81:823-826.
    • Findley, J.S. 1960. Identity of the long-eared myotis of the southwest and Mexico. J. Mammal. 41:16-20.
    • Flath, Dennis L., 1979, Nongame species of special interest or concern: Mammals, birds, reptiles, amphibians, fishes. January 1979.
    • Foresman, K.R. 2001. The wild mammals of Montana. American Society of Mammologists, Special Publication Number 12. Lawrence, KS. 278 pp.
    • Genoways, H.H., and J.K. Jones, Jr. 1969. Taxonomic status of certain long-eared bats (genus Myotis) from the southwestern USA and Mexico. Southwest. Nat. 14:1-13.
    • Hendricks, P. 2000. Preliminary bat inventory of caves and abandoned mines on BLM lands, Judith Mountains, Montana. Montana Natural Heritage Program, Helena, Montana. 21 pp.
    • Hendricks, P., J. Carlson, and C. Currier. 2003. Fatal entanglement of Western Long-eared Myotis in burdock. Northwestern Naturalist 84:44-45.
    • Hendricks, Paul., 1998, Bats surveys of Azure Cave and the Little Rocky Mountains: 1997-1998. November 1998.
    • Jones, J. Knox Jr. and J.R. Choate. June 1978. Distribution of two species of long-eared bats of the genus Myotis on the Northern Great Plains. Prairie Nat. 10(2):49-52.
    • Madson, M., G. Hanson, S. Martinez, and D. Genter. 1993. Wintering bats in Montana: results of surveys in the Pryor Mountains with annotation on area caves and mines. Montana Natural Heritage Program. Helena, MT. 36 pp.
    • Manning, R. W. and J. K. Jones, Jr. 1989. MYOTIS EVOTIS. Mamm. Species 329:1-5.
    • Marcot, B. G. 1984. Winter use of some northwestern California caves by western big-eared bats and long-eared Myotis. Murrelet 65(2):46.
    • Maxim Technologies, Inc., 2002, Western Energy Company Rosebud Mine, Colstrip, Montana: 2002 Annual Wildlife Monitoring Report; December 1, 2001 - November 30, 2002. Febr. 24, 2002.
    • Reid, F. 2006. Peterson Field Guide to Mammals of North America, 4th Edition. Houghton Mifflin Company: Boston and New York, 608 pp.
    • Solick, D. I., and R. M. R. Barclay. 2006. Morphological differences among Western Longeared Myotis (Myotis evotis) populations in different environments. Journal of Mammalogy 87:1020-1026.
    • van Zyll de Jong, C.G. 1979. Distribution and systematic relationships of long-eared Myotis in western Canada. Can. J. Zool. 57:987-994.
    • Vonhof, M. J., and R. M. R. Barclay. 1997. Use of tree stumps as roosts by the Western Longeared Bat. Journal of Wildlife Management 61 :674-684.
    • Waage, Bruce C., 1991, Western Energy Company Rosebud Mine, Colstrip, Montana: Annual Wildlife Monitoring Report, 1990 Field Season. September 1991.
    • Waage, Bruce C., 2001, Western Energy Company Rosebud Mine, Colstrip, Montana: 2000 Annual Wildlife Monitoring Report; December 1, 1999 - November 30, 2000. March 30, 2001.
    • Western Technology and Engineering, Inc. (WESTECH)., 1994, Wildlife Monitoring Absaloka Mine Area Annual Report, 1994. Montana SMP 85005. OSMP Montana 0007D. Febr. 24, 1994.
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Citation for data on this website:
Long-eared Myotis — Myotis evotis.  Montana Field Guide.  Montana Natural Heritage Program and Montana Fish, Wildlife and Parks.  Retrieved on May 24, 2016, from