Long-Legged Myotis
Rounded, short ears distinguish this common bat from the little brown myotis.
About This Species
This is Colorado's only medium-sized, short-eared myotis with a keeled calcar (the spur of bone that projects inward from the ankle and helps to support the uropatagium) and one of Colorado's most common bats. It is a fairly heavy-bodied bat, and the medium to dark brown fur on the back extends to the tail membrane. The short ears appear more round, less pointed than those of other species. Hairs of the venter are paler than those of the back and may even be buffy. The underside of the wing usually is well furred to the elbow. Tips of individual hairs may appear slightly burnished. The species most readily confused with the long-legged myotis is the little brown myotis, which differs in having relatively longer ears, lacking the distinct keel on the calcar and frequently having paler pelage.
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
Mean measurements of six males and nine females from Park County were: length, 97.3 and 102 mm; length of forearm, 37.8 and 38.2 mm; weight, 8.7 and 11.2 g. The wingspan is 250-270 mm.
Range
This species occurs throughout much of western North America from central Mexico to extreme northwestern British Columbia and from the Pacific Coast to the western margins of the Great Plains. The animals occur across the western three-fifths of Colorado and the wooded mesas of southeastern Colorado at elevations ranging from about 5,000 to 11,500 feet. This is the most common myotis at higher elevations in the state ranging up into the subalpine.
Habitat
The long-legged myotis is a generalist species using a range of habitats including wooded areas in foothills, mountains and high plateaus. Typical habitat is montane or subalpine forest, ponderosa pine woodland, pinyon-juniper woodland and montane shrubs with willows or well-watered stands of sagebrush. The animals roost by day in buildings, mines, fissures in rocks or beneath loose bark on trees. Usually they roost singly or in small groups. Night roosts are in dark places like caves or mines. Winter haunts of Colorado individuals are largely unknown, but they are thought to hibernate locally, making short migrations, as late fall activity has been observed at mines and caves. Elsewhere, they are known to hibernate singly in mines or caves.
Diet
The long-legged myotis mostly eats moths. They emerge to feed early (while it is light enough to observe them distinctly) and forage at heights of three to four meters over ponds, streams, open meadows or forest clearings, cruising a repetitive circuit through the evening. Flight is more relaxed and leisurely than that of other medium-sized species of Myotis, and experienced observers can distinguish it by the flight pattern.
Reproduction
Pregnant females form nurseries of up to a couple hundred individuals in buildings, crevices or trees. Males are segregated and solitary during the maternity season. In Colorado, males with scrotal testes have been captured in July and August. It has been noted that the long-legged myotis has a particularly long parturition season. Pregnant females have been noted from June to early August in Colorado and elsewhere, and births are spread throughout the summer. Lactating females are most abundant in samples beginning in August. Females apparently breed their first winter. Reproduction in this species has not been studied in detail.