southeastern United States. Summer and winter (hibernation) ranges overlap but are not identical. Hibernation occurs in caves in northern Alabama, northern Arkansas, Kentucky, Missouri, and Tennessee. During summer, the species ranges further and can be found in eastern Oklahoma and Kansas, southern Illinois and Indiana, southwestern Virginia, western North Carolina and northwestern Georgia. A very small number of records from West Virginia and Mississippi are considered to represent vagrants. Historically attested populations in Florida appear to be absent as of 2020. Gray bats are cave obligate (or cave dependent) bats, meaning that with very few exceptions (in which cave-like conditions are created in man-made structures like sewers and culverts) gray bats only live in caves, not in abandoned barns or other structures as other species of bats are known to do. Less than 5% of all available caves are inhabited by gray bats. Thus, any disturbance to these cave habitats can be extremely detrimental to gray bat populations. Cave characteristics Although the habitat range of the gray bat incorporates much of the southeastern United States, the largest summer colonies of gray bats are located within the Guntersville Reservoir. This reservoir, found in northeastern Alabama, contains the Sauta (formerly Blowing Wind) and Hambrick caves which can accommodate over 200,000 gray bats combined. Gray bats use caves differently at different times of the year. For example, populations of gray bats tend to cluster in caves known as hibernacula to prepare for winter hibernation. In contrast, their populations disperse during the spring to establish sexually segregated colonies. Females form maternity colonies (also known as summer maternity roosts) while males aggregate in non-maternity, or bachelor colonies. These bachelor colonies also house yearlings of both sexes. Gray bats also utilize a third type of cave, the dispersal cave, which they inhabit only during migration. For their hibernacula, gray bats prefer deep, cool caves with average temperatures ranging from 5 to 11 °C. Multiple entrances and good airflow comprise the other characteristics that gray bats find desirable. Winter hibernacula are already cold when gray bats begin arriving in September. Summer caves are usually located along rivers and have temperatures that range from 14 to 25 °C. Summer caves typically contain structural heat traps (including domed ceilings, small chambers, and porous rock surfaces) that capture the metabolic heat from the clustered gray bats, allowing the nursery populations to succeed. Preferred summer colony caves are within 1 km