Western Small-footed Myotis: Myotis Ciliolabrum

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Physical Characteristics Of The Western Small-footed Myotis

Western small-footed myotis are creatures that have wings made of a stretched membrane called a patagium. The average body measurements of the western small-footed myotis:

  • Total Height Height: 87.3mm
  • Wingspan: 205-245 mm
  • Ear Length: 11-16mm
  • Weight: 5.88g
  • Tail Length: 1.5-2.0mm
  • Foot Length: 9mm
  • Forearm Length: below 34mm
  • Total Teeth: 38

In western small-footed bats, sexual dimorphism has been suggested, as females can be larger than males. In Nevada, Bat weights reported that females were averaging 4.7g, while males were only 4.0g. Also, bats are larger in the southern portion of the range than those in the range’s northern end.

These bats have black masks on their faces, and they have dark ears and forearms, too. Depending on the subspecies, their fur is yellow or buff-colored. There is a much lighter pelage in Myotis ciliolabrum than in Myotis ciliolabrum melanorhinus.

Pups are born fur-less, about 1.1 to 1.6g in weight. Anecdotal measures have reported neonates with forearm lengths of 12.4m and total lengths of 20mm. 1Go To Source animaldiversity.org -“Myotis ciliolabrum western small-footed myotis”

Learn More: American Bats

Western Small-footed Myotis Behavior

In canyon walls, caves, mining tunnels, behind loose tree bark, or abandoned houses, her daytime roosts may be in cracks and cracks. These bats do not winter in Texas, as specimens were only taken from March through July.

This bat species is known to hibernate in suitable caves or mine tunnels within their summer range in other sections of their distribution. In the rock ceilings of old mines, bats observed in winter are often found wedged deeply into narrow cracks and crevices. They were able to fly when examined from these crevices, which suggests that they do not go into deep winter sleep.

They can feed on water and desert chaparral vegetation close to the ground. This bat is powerful enough to take off from the water’s surface. 2Go To Source depts.ttu.edu -“WESTERN SMALL-FOOTED MYOTIS Myotis ciliolabrum (Merriam 1886)”

Reproduction Habits Of The Western Small-footed Myotis

This bat follows a typical mating pattern in the fall, storage of sperm in the winter, and fertilization in the spring following ovulation. Records indicate that the single young born annually appears in late May to early July and begins to fly about 1 month later.

Habitats The Western Small-footed Myotis Call Home

Despite its wide presence, this species’ habitat preferences are little known, although it is known to inhabit rocky areas and is more prevalent at lower elevations. Summer roosts include rock crevices, buildings, mines, under bark on trees, under stones, and various other sites and are highly variable.

Western Small-footed Myotis is a reclusive species. The small-footed myotis is a resident of Colorado throughout the year. It hibernates alone or in small groups in caves, mines, and possibly rock crevices. Despite its small size, at low temperatures and low humidity, it is known to hibernate in open tunnels, a situation one would assume is stressful. It sometimes hibernates near other bats at elevations up to 9,500 feet, including Townsend’s big-eared bat. 3Go To Source us-parks.com -“WESTERN SMALL FOOTED MYOTIS

Range Of The Western Small-footed Myotis Species

M. Ciliolabrum ranges from British Columbia, Alberta, and Saskatchewan in Canada, throughout the western half of North America, through most of the United States west of the 100th Meridian, and into central Mexico. In deserts, chaparral, riparian zones, and western coniferous forest, ciliolabrum occurs; above the pinon-juniper forest, it is most common. In Texas, these bats are found primarily in the region of Trans-Pecos. 4Go To Source tpwd.texas.gov -“Western Small-footed Myotis (Myotis ciliolabrum)”

Western Small-footed Myotis Diet

Little is known about the diet of the western small-footed myotis. In the guts of the few specimens thus far studied, moths, beetles, flies, and caddisflies have been found. All these prey presumably are taken on the wing relatively close to the ground. 5Go To Source webapps.fhsu.edu -“WESTERN SMALL-FOOTED MYOTIS Myotis ciliolabrum”

Conservation Of The Western Small-footed Myotis

Closure of abandoned mines without adequate surveys and recreational caving may affect western small-footed myotis. Water source poisoning from contaminants is also a possibility.



  1. Thomas, D. 2019. “Myotis ciliolabrum” (On-line), Animal Diversity Web. Accessed January 04, 2021 at https://animaldiversity.org/accounts/Myotis_ciliolabrum/
  2. Schmidly, David, and Robert Bradley. “A Species Account of the Western Small-Footed Myotis (Myotis Ciliolabrum) | Mammals of Texas | Natural Science Research Laboratory | TTU.” Texas Tech University Natural Science Research Laboratory, Texas Tech University, www.depts.ttu.edu/nsrl/mammals-of-texas-online-edition/Accounts_Chiroptera/Myotis_ciliolabrum.php. Accessed 4 Jan. 2021.
  3. U.S. National Parks. “Western Small Footed Myotis.” US-Parks.Com, www.us-parks.com/nature-and-wildlife/mammals/western-small-footed-myotis.html. Accessed 4 Jan. 2021.
  4. Texas Parks And Wildlife. “Western Small-Footed Myotis (Myotis Ciliolabrum).” Texas Parks And Wildlife, tpwd.texas.gov/huntwild/wild/species/westsmfoot. Accessed 4 Jan. 2021.
  5. “Kansas Mammal Atlas: Western Small-Footed Myotis.” Sternberg Museum of Natural History, Fort Hays State University, webapps.fhsu.edu/ksmammal/account.aspx?o=32&t=175. Accessed 4 Jan. 2021.