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Montana Animal Field Guide

Montana Field Guides

Yuma Myotis - Myotis yumanensis

Potential Species of Concern

Global Rank: G5
State Rank: S3S4

Agency Status


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General Description
Similar appearance to, and difficult to distinguish from, Little Brown Myotis.

Species Range
Montana Range

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Western Hemisphere Range


Range Comments
The species' distribution in the state is uncertain due to the difficulties in differentiating it from the Little Brown Myotis (Myotis lucifugus). Acoustic surveys in northwestern Montana and museum vouchers identified with skull measurements indicate the species is present west of the Continental Divide, but genetic confirmation is needed.

Summary of Observations Submitted for Montana
Number of Observations: 50

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Relative Density



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

Found near water in dry coniferous forests and arid shrublands. Summer day roosts include buildings, bridges, mines, and bat houses, sometimes caves and trees. Hibernacula not described.
Food Habits
Often prey on beetles as well as a variety of soft-bodied insects including flies, mosquitoes, mayflies, moths, and termites.

Emerge when it is nearly dark, often foraging low over water. Sexes segregated; males roost singly or in small groups. Maternity colonies can include several hundred individuals. Females have one young, usually born in late June or July. April records in Montana could be spring migrants.

Reproductive Characteristics
This bat has only one young per year, and nothing is known about the mating and social system or natal sex ratio of this species. Mating is expected to be non-selective as in the Little Brown Myotis (Milligan 1993).

  • Literature Cited AboveLegend:   View Online Publication
    • Milligan, B.N., and R.M. Brigham, 1993. Sex ratio variation in the yuma bat (MYOTIS YUMANENSIS). Can. J. Zool. 71:937-940.
  • Additional ReferencesLegend:   View Online Publication
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    • Aldrich, Hugh. 1986. Manoeuverability and ecological segregation in little brown (MYOTIS LUCIFUGUS) and Yuma (M. YUMANENSIS) bats (Chiroptera: Vespertilionidae). Can. J. Zool. 64:1878-1882.
    • Berts, B. J. 1997. Microclimate in Hell's Canyon mines used by maternity colonies of Myotis yumanensis. Journal of Mammalogy 78:1240-1250.
    • Brigham, R.M. August 1992. Variation in Habitat Use and Prey Selection by Yuma Bats, Myotis yumanensis. Journal of Mammology 73(3):640-645.
    • Dalquest, W.W. 1947. Notes on the natural history of the bat, Myotis yumanensis, in California with a description of a new race. Amer. Midl. Nat. 38:224-247.
    • Harris, A. H. 1974. MYOTIS YUMANENSIS in interior southwestern North America with comments on MYOTIS LUCIFUGUS. J. Mammal. 55:589-607.
    • Herd, R. M. and M. B. Fenton. 1983. An electrophoretic, morphological, and ecological investigation of a putative hybrid zone between MYOTIS LUCIFUGUS and MYOTIS YUMANENSIS (Chiroptera: Vespertilionidae). Can. J. Zool. 61:2029-2050.
    • Parkinson, A. 1979. Morphological variation and hybridization in Myotis yumanensis sociabilis and Myotis lucifugus carrisma. J. Mammal. 60:489-504.
    • Rodhouse, T. J., S. A. Scott, P. C. Ormsbee, and J. A. Zinck. 2008. Field identification of Myotis yumanensis and Myotis lucifugus: a morphological evaluation. Western North American Naturalist 68:437-443.
    • Van Zyll de Jong, C.G. 1985. Handbook of Canadian mammals. Volume 2. Bats. National Museums of Canada, Ottawa. 212 pp.
    • Weller, T. J., S. A. Scott, T. J. Rodhouse, P. C. Ormsbee, and J. M. Zinck. 2007. Field identification of the cryptic vespertilionid bats, Myotis lucifugus and M. yumanensis. Acta Chiropterologica 9:133-147.
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Citation for data on this website:
Yuma Myotis — Myotis yumanensis.  Montana Field Guide.  Montana Natural Heritage Program and Montana Fish, Wildlife and Parks.  Retrieved on May 24, 2016, from