Big Free-Tailed Bat
Big free-tailed bats are found in deserts and arid grasslands, where they roost in rocky outcrops and cliffs.
About This Species
Like the Brazilian free-tailed bat, these animals have a tail that extends well beyond the uropatagium. This bat is much larger than the Brazilian free-tailed bat, and its ears join at the midline of the forehead. Color varies from pale brown to black.
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
Wingspan is approximately 425 mm. Average measurements are: total length, 140 mm; length of ear, 25 mm; length of forearm, 60 mm.
Range
The big free- tailed bat occurs mainly in southern California, Arizona, New Mexico, Texas and Mexico. Relatively few individuals have been documented in Colorado, on both sides of the Continental Divide and as high as Gunnison (at 7,700 feet). Long thought to be an accidental wanderer in Colorado, recent data now suggest the presence of breeding colonies has been confirmed in western Colorado.
Habitat
This bat frequents rocky or canyon country where it roosts in crevices of high cliff faces. This migratory species is a swift, powerful flier, and occasional individuals wander as far north as Canada. Little is known of mortality and longevity.
Diet
Moths seem to be the mainstay of their diet, although little data has been collected. This bat emerges late in the evening and forages at high altitudes.
Reproduction
Breeding probably occurs in midwinter while the species is in warmer latitudes. A single young is born in mid-June to early July. Females form nursery colonies, and the young do not leave the nursery until they are almost full grown.