WILDLIFE IN RYERSONS WOODS
Bats
Lasionycteris

There are twelve species of Bats flying through, or living in Illinois. Two are on the federal and state endangered species lists: the Indiana bat (Myotis sodalis), and the gray bat (Myotis grisescens). At least three make their homes at Ryerson Woods: the little brown bat (Myotis lucifugus), the big brown bat (Eptesicus fuscus) and the red bat (Sasiurus borealis).

Bats are the only mammals that fly. The bones in a bat's wing correspond to the bones in the arms and hands of humans. Unlike "flying" squirrels who glide, the bats really do fly. Some species may climb up to 10,000 feet during migration. In fact, flying is what they do best. Bats are unable to walk, though if necessary, they can drag their bodies with their wings.

Bats are not blind. Actually, they can see when they are out at night, but most rely on a sophisticated "sonar" echolocation system to help them find food and avoid obstacles in total darkness. They emit ultrasonic sounds that echo off the objects and are picked up by their very sensitive ears.

Illinois bats feed exclusively on insects. As the major predator of the night flying insects, they have plenty to feed upon during the summer months and can easily consume 3,000 insects in one night. Moths and mosquitoes, look out!

The Illinois bats are true hibernators which means that their body temperature drops when it gets cold. Bats can't tolerate temperatures below freezing. So in the winter, they move to caves which have constant, though cool, temperatures, or migrate to warmer areas. They usually migrate to the same places year after year to hibernate and return to the same attics and trees each spring.

Bats mate in flight at the end of summer and most species give birth to one offspring each year. It is interesting to note that since they lose so much body fat during their winter hibernation, though they mate at the end of summer, gestation doesn't begin until the following spring. Though tiny and hairless at birth, the young bats grow quickly and learn to fly in only three to five weeks.

Big and little brown bats are common in Illinois. In the winter they hibernate in caves; in the summer they move to attics, sheds or hollow trees. Some may form large colonies with hundreds of bats. It is quite a sight to see a large colony flying from a rooftop at dawn or dusk on their way to feeding, and returning together when they are done.

Red bats are rarely the bats found in homes. They roost in the foliage of trees in the summer, away from human populations, and are very hard to spot, though they may be seen when they venture out hunting for insects around street lights. In the winter, they migrate south to somewhat warmer regions to hibernate in hollow trees. Their red fur is white at the tips, making them look a little frosted even in the summer. Red bats,unlike other bats, have twins each year.

Let's straighten out a few myths:

• Bats are not blind
• Bats do not get tangled in people's hair
• Bats rarely carry rabies; only a handful of people in the U.S. ever have contracted rabies from bats
• Bats are not dirty; they groom themselves and have few parasites and those do not normally infect humans; however, their droppings, like bird droppings (more commonly), may have a fungus which can give some humans flu-like symptoms
• Bats don't attack humans...actually they are afraid of us; most bites occur from handling 'defensive' grounded bats

And to give them special credit, remember that bats:

• Control insects
• Have been used in the development of vaccines
• Have contributed to the study of navigational aids for the blind
• Are used in research on aging and space biology
  

Next time you see bats flying around a street lamp, remember what valuable members of our ecosystem they are!