Hobbies And Interests
Distinquishing the Indiana Bat from the Little Brown Bat
Indiana brown bats grow to just under 2 inches in length and weigh only from 2/10 to 3/10 of an ounce. They are most easily distinguished from their relative, the little brown bat (Myotis lucifugus) by having pink lips or a pink nose. They also have a cartilage extending at right angles from the wrist joint of their forelegs known as a calcar. This thumb-like appendage has a curve toward the end like that of the front of a row-boat. This is known as the keel. The calcar of the little brown bat is straight. The Indiana bat has brownish-black fur that is less glossy than that of the little brown bat. It also has small hind feet which are only slightly haired, with hair ends not extending beyond the toe tips.
The Indiana Bat Life Cycle
Females and males mate in August or early September. However, the female holds the male's semen until they leave hibernation in late March or early April, at which point the females fertilize their eggs and become pregnant. Females separate from the males after hibernation while females congregate in nursery colonies, often under the dead bark of trees or in tree hollows. Females give birth to one pup, born late in June or early in July. The pups are ready to fly after just one month.
Endangered Status
The Indiana bat's numbers are declining despite efforts at protection. This decrease appears to be due to habitat destruction. The bats prefer limestone caves, known as hibernacula, for winter hibernation that have temperatures ranging between 39 and 46 degrees Fahrenheit and a humidity of 86 percent. Because of these narrow requirements, 85 percent of the bats hibernate in only nine locales. Efforts at restricting human incursion into caves also restrict the bat's use of suitable caves. Barriers alter temperatures and humidity levels and make caves they might use less attractive. Flooding and human vandalism also play parts in habitat destruction for these bats.
Other Threats
Even well-meaning cavers can disrupt the hibernation of the Indiana bat. A bat roused from hibernation has to use hard-won fat stores during the time of wakefulness for energy. This means they have less energy to see them through hibernation. In addition, pesticide use has an impact on Indiana bat insect food sources.