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
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'
And to give them special
credit, remember that bats:
Control insectsHave been used in the development of
Have contributed to the study of navigational aids for
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!