National Park Service Klamath Network Featured Creature U.S. Department of the Interior

Natural Resource Stewardship & Science Klamath Network Little Brown Bat August 2016 Myotis lucifugus

Less is known about their winter Conservation roosts in the West, which appear to be Little brown bats were a common less populous and more dispersed. species until the arrival of a deadly disease in New York in 2006: White Reproduction and Life History Nose Syndrome (WNS), caused by the In the fall, little brown bats fungus, Pseudogymnoascus congregate at “swarming” sites destructans. Over 6 million bats in outside of cave or mine entrances to North America have succumbed to it, mate. Females actually delay including over 1 million little brown fertilization until spring, storing the bats. The fungus gives the muzzle a Little brown bat cluster. FWS/Keith Shannon. sperm overwinter. After a 2-month powdery white appearance and pregnancy that begins in spring at Field Notes infects the skin, damaging wing tissue maternal nursery roosts, females give essential to flight. Bats with WNS also General Description birth to one pup in the summer, which deplete precious fatty deposits over The little brown bat, or little brown they catch in their tail membranes as it the winter by waking up more myotis, is a member of the large and emerges. Most little brown bats live frequently (as often as every 2–4 days) well-known Vespertilionidae family of just under a decade, but some live up than normal (every 13–15 days). Until bats. With a wingspan of 9 to 11 to 20–30 years, making them one of WNS was detected in Washington inches, it weighs only about half an the longest-lived small mammals. State in March 2016, the disease was ounce. Its specific name, lucifugus, concentrated in the eastern US. Little comes from the Latin “lux,” for light, Diet brown bat populations appear to be in and “fugio,” meaning to flee—true to Little brown bats forage over water severe decline as a result of WNS. its nocturnal nature. Its variable for insects, such as midges, coloring tends to be cinnamon-buff or mosquitoes, mayflies, and caddisflies. brown on the back and yellowish or They also hunt moths, beetles, and olive brown underneath. The fur on other insects over forested and open landscapes. Little brown bats can eat its back has a metallic sheen, and its ears are glossy dark brown. up to 1200 insects an hour during their peak feeding time—sparing us all Habitat and Range

a few mosquito bites. WNS symptoms: s This species ranges from Alaska south white muzzle to central Mexico, although its core Behavior (above); damaged wing tissue (right). population is in the northeastern US. As daylight fades, these bats emerge FWS photo from daytime roosts to feed, being Where to See While little brown bats occupy a wide most active during the first 2 to 3 The little brown bat is probably present at range of habitats, including forests, hours after sunset, and then again for Whiskeytown NRA and occurs in all of the shrublands, and grasslands, they need a second bout of foraging after remaining Klamath Network parks. access to protected roosting sites. In midnight. By bouncing sound waves the summer, they’ll find dark, warm off objects (echolocation) up to 200 References and Further Reading roosting sites in the attics of buildings, times/second, these bats can zero in under bridges, in hollow trees, and in Bat Conservation International: on tiny insects in complete darkness. http://www.batcon.org/ caves. Over the winter, in the eastern A smaller appendage (the tragus) at US, they’ll congregate in the tens and the base of the large outer ear helps to Western Bat Working Group http://wbwg.org/western-bat-species/ thousands to hibernate in moist caves pinpoint their targets. or mine shafts that keep a constant https://www.whitenosesyndrome.org/ temperature—just above freezing. EXPERIENCE YOUR AMERICATM August 9, 2016