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| Photo of Indiana Bat |
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Class: Mammalia
Order: Chiroptera
Family: Vespertilionidae
Genus: Myotis sodalis
The Indiana Bat was first discovered in Indiana in 1928. On March 11, 1967 the Indiana Bat was designated as Endangered in its entire range. It can be found in Alabama, Arkansas, Georgia, Iowa, Illinois, Indiana, Kansas, Kentucky, Maryland, Michigan, Missouri, Mississippi, North Carolina, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Viginia, Vermont, and West Virginia.
Sadly the population has been declining since the 1960's. Their winter caves are entered by people who disturb the bats and alter the cave temperature. They always return to their birth caves and unfortunately very few of these caves remain undamaged. The Indiana bat breeds during the summer in forests near wetlands which also have been affected by development and logging.
In the 1950’s the estimated population was 808,000 to approximately 350,000 in 1997.
The scientific name for the Indiana Bat is Myotis sodalist. It comes from two Greek words meaning mouse ear and the word sodalist which is Latin for- companion. This name was given because they tend to hibernate in large groups known as clusters. They are also called the social bat.
Appearance and Life Span
The Indiana Bat is only about the size of a house sparrow at 3 inches tall. It’s fur is grayish chestnut in color with pinkish to cinnamon under parts, pink lips and nose with pinkish forearms. Their average life span is 10-20 years althouth they can live up to 30 years!
Benefiting the environment
The Indiana Bat’s diet is insects. These bats help keep insect numbers under control and will eat pests such as gypsy moths and alfalfa weevils. They eat a variety of night flying aquatic and terrestrial insects along rivers, lakes and upland areas. They also add to the biological diversity of forest communities.
Habitat
Indiana bats hibernate in the winter in caves and abandoned mines. They prefer limestone caves. Some caves can support over 80,000 bats. More than 85% of the population hibernates in only nine sites. The caves must be draft-free and have a constant temperature (39-46 degrees F.). During the summer, they roost at the edges of hardwood forests. Males will roost alone or in small groups but females are found in larger groups of up to a 100 bats.
Reproduction
Indiana Bats mate in the fall just before they hibernate. The females store the sperm during the winter hibernation and become pregnant in the spring. They roost under peeling bark of dead or dying trees to have their young. These young are called pups and they have only 1 per year.
Why is the Indiana Bat Endangered?
Humane disturbance is one of the leading causes of their decline. They tend to live together in large groups in only a few caves. They become very vulnerable to even samll disturbances. A significant portion of the population can be affected by events such as the increase in cave temperature. For example, during the winter, a camper using a cave may set a campfire and alter the natural temperature. During the winter months bats do not eat. They store enough food to sustain them until the spring. If they are disturbed, they become aroused and can use up to 10-30 days of stored fat.
Another problem occurs with cave commercialization and improper gating. A gate or structure placed on a cave or mine entrance may prevent bat access or changes in the air flow, temperature, humidity or amount of light, and can have disastrous consequences.
Low birth rate is a serious problem. Since mating will produce 1 pup a year along with a potentially high death rate, it can take years for the species to recover.
Other reasons for their decline are speculation and include habitat loss or degradation and exposure to agricultural chemicals. Many midwestern forests have evolved into urban and agricultural uses which resulted in the loss of forest habitat. Pesticides may kill the insects that bats eat. They also may eat contaminated insects, drink contaminated water, or absorb chemicals when feeding in recently treated areas.
Steps to Recovery
There are many ways we can help in the recovery of these bats. One of the key ways is to avoid disturbing hibernating bats. They tend to hibernate near the entrance of caves so it is quite easy to disturb them. People should avoid caves that are known to have a hibernating bat population. People should also respect signs and gates constructed to notify people of resident bats. And remember- Avoid building fires in or near a cave’s entrance.
Additional recovery efforts include: Placing gates or fences across caves entrances that do not disturb the air flow but allow the bats free access to the caves. Maintaining vegetation around cave entrances. Efforts should also include minimizing the removal of timber (live and dead) from known habitat areas- especially during the summer when they have their young. They favor oak and hickory but will also use cottonwood and elm trees.
Another way to help protect these bats is to reduce the use of pesticides near their summer foraging areas. Spraying should be avoided near their roosting areas.
Recovery Prognosis
The wintering population in Indiana appears to be increasing and in the state of Kentucky the population has remained stable. A better understanding of their summer habitat requirements may help their survival. Little is known about the factors that do affect their survival and reproduction. Unfortunately, until the factors that do effect their population negatively are removed, the recover will be very slow primarily due to their low reproductive rate. Since nearly 85% of the known population winters in only 7 caves and mines in Missouri, Indiana, and Kentucky and one-half of the population use two caves, it becomes increasingly important to protect these areas if the species is to survive.
For more information, vist the links provided. |
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