The Indiana myotis, or Indiana bat, is a medium-sized bat; it is one of six Missouri species in genus Myotis (the mouse-eared bats). Indiana bats have brownish-gray fur with cinnamon overtones. The ears and wing membranes are blackish brown. The nose is pinkish. Indiana bats are difficult to distinguish from our other myotises (mouse-eared bats).
In addition to the coloration described above, note the following:
- A distinct keel is present on the calcar (the cartilaginous supporting structure on the rear edge of the tail membrane). (The eastern small-footed myotis also has a calcar keel, but that bat is smaller and has a different coloration, including a black mask, which the Indiana bat lacks.)
- The wing is attached along the side of the foot, all the way to the base of the toes.
- The toe hairs are shorter than the toes (this helps distinguish the Indiana bat from the little brown bat).
Similar species: Missouri has five other species of bats in genus Myotis:
- Southeastern myotis (M. austroriparius)
- Gray myotis (M. grisescens)
- Eastern small-footed myotis (M. leibii)
- Little brown myotis (M. lucifugus)
- Northern long-eared myotis (M. septentrionalis)
For more information about Missouri’s bats as a group, visit the Bats page.
Total length: 69–98 mm (2¾–3⅞ inches); tail length: 28–50 mm (1⅛–2 inches); weight: 6–10 g (about 0.2–0.4 ounce); forearm length: 35–41 mm (about 1⅜–1⅝ inches); wingspan: 24–27 cm (about 9½–10½ inches).
More than 85 percent of Missouri's total population of Indiana myotises hibernate in only eight specific locations, three of which are located in Shannon, Washington, and Iron counties of Missouri. Summer roosting Indiana myotises have been recorded in northern Missouri.
Habitat and Conservation
In summer, Indiana myotises live in wooded habitats, often roosting under loose bark of trees such as shagbark hickory.
For winter hibernation, Indiana myotises need cool caves with stable temperatures of around 40F and relative humidity of 66–95 percent. Of Missouri's more than 7,000 known caves, only 27 ever had sizable populations of this species.
Historically, Indiana bats suffered major declines due to habitat loss and disturbance of hibernation and maternity sites, though more recently white-nose syndrome has become the largest threat. That disease caused an approximately 10 percent annual decline between 2006 and 2009.
Conservation efforts include avoiding disturbing hibernating bats and nursery colonies, maintaining cave habitats, improving streamside habitats, and reducing use of pesticides.
Food
Indiana myotises are insectivores, eating primarily moths and beetles but also true flies, true bugs, and aquatic insects such as caddis flies and stone flies. These insects are captured and eaten in flight.
Status
Listed as endangered by the Missouri Department of Conservation and by the U.S. Fish and Wildlife Service.
Life Cycle
Indiana myotises spend summers along streams and rivers in north Missouri, raising their young under the bark of certain trees.
They hibernate through the winter in caves and abandoned mines (never in houses) in the Ozarks. Females enter hibernation in early autumn, shortly before the males. This species hibernates in clusters of several hundred to several thousand.
They emerge from hibernation in early spring and begin migrating to their summer roosting and foraging areas.
Indiana bats ordinarily live for only 5–9 years, but they can live to be at least 20 years old.
Control
Human Connections
Myotis bats together consume hundreds of tons of flying insects per year, including many crop pests and other insects that are troublesome to people.
Meanwhile, pesticide use, habitat disruption, and disturbance during habitation negatively impact the populations, and possibly the existence, of these agile little flyers.
Hannibal, Missouri, has incorporated Indiana bat conservation into what is now its second-largest city park. The Sodalis Nature Preserve was created to protect the bat species the park was named for. The nonprofit Conservation Fund enabled the purchase of the property. The park has miles of hiking and biking trails and provides nature education opportunities. But within the preserve, more than 200,000 Indiana bats — about one-third of the species' global population — hibernate in the extensive network of a former limestone mine and nearby caves. Gates at the mine entrances allow bats to move freely in and out while excluding people from the sensitive colonies. People, however, come to watch the bats emerge at night in spring and summer. The highest concentration is when the bats swarm in October.
This species is called the Indiana bat because the first described specimen came from that state. The species name, sodalis, means "companion" (as in the word sodality — a brotherhood, community, or society); it refers to this bat's habit of hibernating in great masses.
Ecosystem Connections
Bats not only control populations of night-flying insects but also play an important role in the cave ecosystems that most of us rarely see or even think about. Yet healthy caves and springs harbor many unique life forms and are an important Missouri natural resource.
