Going Batty

Images of the Month:

Sound Recordings of Bat Calls

Recording of the Call of a Hoary Bat

The Call of a Big Brown Bat

Have you ever used a magnifier to see something small? How about a microscope? Microscopes let us see things we could not see just using our “naked eyes”.

Special equipment allows us to measure and “see” sounds.

We measure length in inches, feet, miles, kilometers, etc. We measure the pitch of a sound (how high or low it is) with a unit called a hertz, named for a famous German inventor named Heinrich Hertz. He was the first person to send and receive “radio waves”.

The pitch of “Middle C” is about 262 hertz. In the “picture” of the bat sound, the Y axis of the graph is labeled kilohertz. One kilohertz equals 1000 hertz.

Humans cannot hear sounds with a pitch higher than about 20 kilohertz (20,000 hertz). Bats emit sounds much higher in pitch than that. Using this special equipment lets bat biologists study sounds humans cannot even hear!

For example, a bat researcher can record bat calls in a certain area and later tell what kind of bats they were. (Can you tell the difference between the calls of the hoary bat and the big brown bat?)

Bats of Tennessee

Did you know that 13 different kinds of bats live in Tennessee? To find out more about one of them, click on its picture.

Common Name		Common Name
Rafinesque's big-eared bat		Eastern small-footed bat
Big brown bat		Little brown bat
Silver-haired bat		Northern bat
Eastern red bat		Indiana bat
Hoary bat		Evening bat
Southeastern bat		Eastern pipistrelle bat
Gray bat

Source: http://www.batcon.org/SPprofiles/

Make a Model of a Little Brown Bat

Source: http://www.batcow.org/images/coloring/cutout-lilbrownbat.jpg

Junior Naturalist Challenge:

Real Little Brown Bats weigh about 7-14 grams (0.3-0.5 ounce) and have a wingspan of about 22-27 centimeters (9-11 inches). Measure the weight and wingspan of your model and compare it to the “real thing”. How could you create one that is "life size" and the right weight?

Last updated on November 2, 2005