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Little Brown Bat
Myotis lucifugus
NatureServe conservation status
Global (G-rank): G3G4
State (S-rank): S3
External links
Species range
The little brown bat is widespread throughout most of the contiguous United States, Canada, and Alaska, and historically was regarded as one of the most common bats in North America. This small bat occurs in all of Utah except for the extreme southeastern corner (Oliver 2000, UDWR data).
Ecology
Members of this species are nocturnal and are found in urban areas, coniferous forests, and other woodlands. They forage over or near water and in open areas among vegetation. In Utah, they are often found at moderately high elevations (Oliver 2000). They have adapted well to man-made structures for summer roosting, although caves and dead or hollow trees are also used. The little brown bat is primarily an aerial insectivore, feeding on mosquitoes, midges, caddisflies, mayflies, moths, various hoppers, small beetles, and sometimes spiders (Whitaker and Lawhead 1992).
In winter, populations hibernate and are believed to use a variety of caves, mines, cliffs, crevices, and rocky talus (Weller et al. 2018). In Utah, the little brown bat is suspected to hibernate in relatively small aggregations. Winter hibernation sites generally have a relatively stable temperature of about 36 to 54 degrees Fahrenheit (Kunz and Reichard 2010).
Threats or limiting factors
The fungal disease, white-nose syndrome (WNS), has resulted in the precipitous decline of little brown bats across eastern North America (Frick et al. 2010). Although the fungus was detected in Utah in 2024, no bats have shown signs of the WNS disease. WNS has spread more slowly in the west, and it is suggested that bats may respond differently to WNS based on alternative hibernation strategies, habitat use, and greater genetic structure (Blejwas et al. 2023). Slow reproductive rates, limited suitable maternity colony availability, nuisance colony eradications, insecticide impacts to prey-base, logging and improper forest management, and inappropriate fire frequency and intensity may all have compounding effects on the little brown bat.
