Bats of the United States and Canada

Gray Bat, Myotis grisescens

162 bats of the united states and canada GRAY BAT (Gray Myotis) Myotis grisescens Endangered–United States Weight is 8-11 grams (0.3–0.4 ounce); wingspan is 27–30 centimeters (11–12 inches). Distribution includes cave regions of Arkansas, Missouri, Kentucky, Tennessee, and Alabama, with occasional colonies in adjacent states. Gray bats are cave residents year-round, but different caves usually are occupied in summer and winter. Few have been found roosting outside of caves. They hibernate primarily in deep vertical caves with large rooms acting as cold-air traps (5–11°C [42–52°F]). In summer, females form maternity colonies of a few hundred to many thousands of individuals , often in large caves containing streams. Maternity colonies occur in caves that trap warm air (14–25°C [58–77°F]) or provide restricted rooms or domed ceilings capable of trapping combined body heat from clustered individuals. Because of gray bats’ specific habitat requirements, fewer than 5% of available caves are suitable for them. Males and nonreproductive females form bachelor colonies in summer . Gray bats primarily forage over water of rivers and lakes. Moths, beetles, flies, mosquitoes, and mayflies are important in the diet, but gray bats also consume a variety of other insects. Mating occurs in September and October, and females enter hibernation immediately after mating, followed by males. Females store sperm through winter and become pregnant after emerging from hibernation. One baby is born in late May or early June; it begins to fly within 20–25 days of birth. Lifespan may exceed 14–15 years. Listed as endangered, about 95% of these bats hibernate in only about 15 caves, making them extremely vulnerable to destruction by humans or from natural catastrophic events. During recent years, numerous roost caves have been gated, resulting in population increases throughout most of this bat’s geographic range. If this trend continues and if it is not decimated by white-nose syndrome, the species will likely be downlisted from endangered to threatened. recto runninghead 163 ...