Description: Townsend's big-eared bats can be distinguished from other Kansas bats by: 1) very large naked ears, 2) long slender tragus, 3) prominent skin glands between the nostrils and eyes, 4) bases of ears meet on the forehead, 5) long, soft pelage that is uniform in color along the shaft of the individual hairs, and is brownish dorsally and lighter ventrally, and 6) relatively thin, dark brown wing membranes. There is no seasonal variation and the sexes are alike. This bat is one of the larger species in Kansas, having a wingspread of 340 mm or more.
Size: Adults may attain the following dimensions: total length 95-105 mm; tail 40-50 mm; hind foot 9-16 m; ear 29-38 mm; weight 8-11 grams.
Range and Habitat: This bat is a year-round Kansas resident and is known only from the southcentral part of the state (Barber, Kiowa, and Comanche counties). It inhabits natural caves, mines, and buildings in the summer and hibernates in small clusters in caves from October to April.
Reproduction: Breeding occurs mostly in autumn and winter. Males separate from females during spring and early summer and are solitary. Sperm are retained in the females' uteri until ovulation. The small maternity colonies are located on cave ceilings or walls. After a variable gestation period (56-100 days), a single naked, blind bat is born between late June and early July. They become covered with light gray fur by about three days of age. Their eyes open and their ears become erect in one week. Although the young are capable of flying at three weeks, they do not forage until a month and a half of age, but are left in the nursery and nursed by the females. A female may continue to nurse her offspring for several weeks after it begins to forage on its own. Young males do not mate during their first autumn, but females are capable of breeding at that time.
Habits: Both sexes of big-eared bats hibernate in small clusters, up to 50 in number, hanging upside down from the ceiling or walls in drier parts of caves near entrances. During the hibernation period in Kansas, there is considerable movement from one area of the cave to another, or even to nearby caves. At other times of the year they fly only at night. Big-eared bats do no leave their roost until well after dark. The flight pattern is near the ground, and rather rapid and twisting. On occasions this bat may hover and flutter. Active bats can rapidly extend or contract their ears; the extended position with ears pointed forward nearly parallel to the body is assumed during flight. The tragus remains extended at all times.
Food: Townsend's big-eared bats emerge late in the evening to feed, taking nocturnal insects in the air, from foliage, or the ground surface. They seem to feed mostly on moths. Following the first foraging trip, they go to night roosts, probably forage again before dawn, and then return to their day roosts shortly before sunrise.
Remarks: Raccoons and snakes that hunt in caves and, to a lesser extent, hawks and owls, are their principal predators. These bats live from four to ten years; maximum longevity recorded is sixteen years.
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