Indiana Bat (Myotis sodalis)

Indiana Bat (Myotis sodalis)

Ryan Chase

The Indiana Bat’s scientific name is derived from latin for “mouse ear companion”, in reference to the species smaller rounder ears, and their social habits. Indiana bats hibernate in closely huddled groups, sometimes hundreds strong. The bats are incredibly light, weighing in around a quarter ounce, and have wingspans up to 11 inches. The Indiana Bat can be identified from other types of bat by the structure of their feet and specific color variations in their fur. They have an insect diet, and will eat up to half their body weight in insects each night. There are approximately 207,000 individuals spanning the eastern US, about half of which are in Indiana

Habitat:

Myotis sodalis rely on caves and occasionally mines for hibernating, but have very limited acceptable temperature ranges. They bats require caves that are under 50º F, but above freezing, which is hard to come by in their range. The bats hibernate because the insects they survive on are not present in winter, and thus the bats must conserve their energy until the spring when food is available again. When spring and summer come around, the bats move to wooded areas, but in different groups. Males roost alone, or in smaller groups, while females cluster in groups in the hundreds.

Reproduction:

Indiana bats have an interesting reproduction cycle. The bats mate before going into hibernation, but the female stores the sperm until springtime, where they impregnate soon after waking from hibernation. They then go into what are known as “maternity colonies”, groups of hundreds of pregnant bats. Each bat has only one offspring, and that pup is cared for throughout the first summer, with the mother only leaving to gather food. 

Threats:

The Indiana Bat is threatened in a few ways. The most concerning is due to human disturbance. The bats do not have many choices when it comes to habitat, so if humans effect just one cave, they can be doing harm to thousands of bats. The largest hibernating group is between 20,000 and 50,000 individuals. Because the bats hibernate in winter, they are not getting any sustenance during this time, and are relying on fat stored from summer and fall. If humans disturb their habitat, the bats may starve before they have a chance to eat again the next year. Human disturbance can come from mine usage, because the bats dwell there as well, or from cave exploring tourists.

The winter months are not the only time the bats are in trouble though. In summer, the bats prefer dead standing trees, which are useless to logging companies, which often remove them. Fragmenting these sites also poses huge problems because the bats prefer large communities, and if there is not enough room for them, they are forced out. Because the bats are located in the Eastern US, there is a lot of farming, and unfortunately for the bats, many farmers use pesticides, which kills off insects, the bat’s food supply, or poisons them.

Recovery Plan:

In 2007, the FWS published a revision to the Indiana Bat’s recovery plan. Currently, the plan aims to monitor the population, conserve the bat’s habitat, research more of the threats to the bats, and improve public education and outreach. The plan is an improvement on the previous version which accounted for the bats wintertime roosting, but was not inclusive of damage done to their summertime locations. To meet the objectives, and to reclassify the bat as threatened, which is the ultimate goal of this recovery plan, we must protect 80% of the Indiana Bat’s habitat permanently, a minimum population count similar to the 2005 estimate of 457,000. At this point, the bats will be up for consideration to be reclassified. See more here

Ways to Help:

The Indiana Bat requires very a specific habitat, so anything that can be done to avoid damaging these areas would help. If you are going on vacation in the Eastern US, avoid going into caves that could be habitat for Indiana Bats. If you live in the Eastern US, and have a dead tree, leave it be, it may be habitat for a variety of wildlife, including the Indiana Bat. If you have crops there, reducing pesticide usage can also help out. 

References:

http://www.fws.gov/midwest/endangered/mammals/inba/inbafctsht.html

http://ecos.fws.gov/docs/recovery_plan/070416.pdf

http://www.wildlife-pros.com/wp-content/uploads/2014/06/Bat-Removal.jpg

http://www.conservewildlifenj.org/images/artmax_275.jpg

https://upload.wikimedia.org/wikipedia/commons/8/85/Indiana_Bat_Range_FWS.jpg