Western Small-Footed Myotis
The western small-footed myotis is very similar to the California myotis.
About This Species
A small bat with a very small (eight mm) foot and dull to burnished brown pelage. The ears are dark, nearly black, and a distinct facial mask is frequent. It is almost impossible to distinguish from the California myotis, and only specialists can tell them apart with certainty.
Like most species of Myotis, the small-footed myotis is often misidentified. It can be confused with the canyon bat or other mouse-eared bats, especially the California myotis. Earlier information on this species in Colorado was published under the names Myotis subulatus or Myotis leibii.
Living with Bats
There are 18 species of bat that call Colorado home. These amazing mammals are not only fantastic insect control, but are also valuable pollinators. Learn more about how humans and bats can live in harmony in our guide.
Bat Conservation
Bats remain one of the most mysterious land mammals, especially in Colorado, where 18 species spend at least part of the year. For example, the little brown bats in our state seem to hibernate differently than those on the east coast, and we are constantly learning about their whereabouts, habitats and behaviors. Our current research suggests that bat populations in Colorado are doing quite well.
One little brown bat can eat up to 18,000 small insects (like mosquitoes) each night. Their economic impact is estimated to be billions of dollars, and much of the agricultural industry relies on their insect control.
Beyond their economic impact, bats flaunt some impressive adaptations. They are the only mammal that truly flies, which requires a very unique anatomy. Their upside-down lifestyle requires adaptations in their “feet” to consistently grip. If people hanged upside down for even an hour, we’d lose consciousness; bats have developed amazing blood pressure accommodations to fit the lifestyle.
We are currently involved in a monitoring partnership called the North American Bat Monitoring Program (NA Bat). The program utilizes acoustic surveys to collect information on bat populations without interfering with their behaviors. We also are using PIT tags, like the chips put in household pets, to monitor a number of maternity sites. While data collection will take years, we’ve already learned new information about Colorado’s bat population, the most heartening of which is that the population appears larger and more widespread than we’d thought. This is an excellent start to learning more about the species, but we’ve got lots of problem-solving and technological innovation left to do.
Our priorities also include learning more about bats so that we are prepared for the potential spread of White-nose Syndrome. Finding and monitoring bats is crucial to this effort, but also comes with its own challenges. Because bats are small, flying mammals, much of the equipment used to track other species is too heavy for them. And during the winter, Colorado bats are very elusive, choosing to hibernate in small groups often in locations that are inaccessible to people.
More Information:
Physical Characteristics
Total length, length of forearm and weight are 80 mm, 30 mm and four g, respectively. The wingspan is about 220 mm.
Range
This bat is widespread and common in the western United States. In Colorado it occurs statewide in suitable habitat. It seems to be most common in the canyon country of the Western Slope and along the Front Range in rocky areas of northeastern and southeastern Colorado.
Habitat
Despite its wide occurrence, little is known of habitat preferences of this species, although it is known to inhabit rocky areas and is more common at lower elevations. Summer roosts are highly variable and include rock crevices, buildings, mines, under bark on trees, beneath stones and a variety of other sites. Individuals are solitary.
The small-footed myotis is a year-round resident of Colorado. It hibernates in caves, mines, and possibly rock crevices alone or in small groups. Despite its small size, it is known to hibernate in open tunnels at low temperature and low humidity, a situation one would assume is stressful. It sometimes hibernates near other bats, including Townsend's big-eared bat, at elevations to 9,500 feet.
Diet
The western small-footed myotis feeds early in the evening on small flying insects such as flies, small beetles and winged ants. This species is highly maneuverable in flight, often foraging among boulders, along cliffs or shrubs and trees.
Reproduction
Little is known about the reproduction of small-footed myotis. Small nursery colonies of 10 to 15 are found occasionally in caves, mines or buildings. One young per year is usual. Young are born in mid-June following a gestation of about two months.