Nature Bulletin No. 147 March 20, 1948
Forest Preserve District of Cook County
William N. Erickson, President
Roberts Mann, Supt of Conservation
squirrels only glide. Bats are the only fur bearing animals that
truly fly, and they've been doing it for at least 50 million years
Twisting, looping and zig-zagging through the air, at dusk and dawn,
they catch flying insects more skillfully than the swallow or the
chimney swift. Each twist and turn means another insect caught, A bat
can consume one-half its weight in insects in a single twilight.
Harmful? No, We have one in Trailside Museum that likes to be
handled and fed mealworms. They do not get in women's hair. They do
not distribute our kind of bed bugs. They are not blind; even in daytime
they see fairly well. But they can fly through timber or the narrow
twisting passages of caves in total darkness because they have radar,
Bats have large specialized ears, Their squeak is pitched so high that
few people can hear it, As they fly they also make a supersonic squeak
about 30 times per second and are guided by the echoes bouncing back
There are two general types: the fruit-eating bats, which are much larger
and found only in tropical regions -- the "flying foxes" of the
Philippines and Malay having a wing-spread as much as five feet -- and
the insect-eating bats. Of the latter, there are over 600 species and sub-
species, including some that eat small fish, some that eat mice, frogs,
birds and other bats, and the blood-sucking vampire In the Chicago
region there are probably eight species: some of them are of the cave-
dwelling type; some are tree-dwellers. Of the cave-dwellers, the
commonest is the Little Brown Bat.
In the summer, this bat is widely distributed, each with its own small
feeding territory, roosting in barns, attics, under eaves, in hollow trees,
or under the loose bark of trees -- since we have no caves. In winter,
most of them hibernate in caves, hanging head-down from the ceilings
and walls in clusters of thousands.
Most bats have only one young per year. When born it is one-fourth as
large as mamma, and she carries it with her as she flies, until it gets too
large and heavy. One of the tree-dwelling bats, a female with four
young ones clinging to her, was found stranded on the ground.
An old bat on a bat gets bats in her belfry.
To return to the Nature Bulletins Click Here!
Update: June 2012