Bats: A nighttime treasure

By Allison Holzer, Interpretive Naturalist, Kroening Interpretive Center

Many years ago, I had the pleasure of sharing my second-story apartment with a bat: he showed up one day, wedged between the storm window and screen of my dining room window. Every evening I would attempt to catch the moment when he would wake up, stretch, and wiggle out from between my windows into the evening, and I while I was able to see this several times, I never did see him arrive in the morning. He stayed for a month or so, and then was gone.

Bats hold a unique spot as the only flying mammals in the world, but there are so many species of bats that they make up about 1/5th of all mammals. The vast majority of bats are insect or fruit eaters, and as such they play important roles keeping insect populations in check or dispersing seeds. Other specialized bats eat nectar, pollen or even fish. There are only three species of vampire bats in the world; they are all found in Central and South America, and rarely bother people, preferring cattle or birds. All seven types of bats found in Minnesota eat insects.

Insect-eating bats are famous for their ability to “echolocate” — as they fly through the air, they produce high-pitched squeaks which travel through the air, hit an object and bounce back to the bat’s ear, much like radar. Their brains use this sound information to determine how far away an object is. In this way they are able to “see” the world with their ears. We can’t hear these sounds, as they are generally too high-pitched for us, but that may be a good thing; if we could hear them we would realize that a bat’s sounds are quite loud. In fact, many bats’ calls are in the range of 100 decibels, which makes them about as loud as a smoke detector.

Once a bat has used its echolocation to find prey (most likely a moth, beetle or cricket) it scoops the insect out of the air with its tail of wing membranes and into its mouth. Some bats can also grab food from the ground or the surface of water with their hind feet, and very small insects can simply be snatched with their teeth. Many of the bats here in Minnesota can eat thousands of insects each night, including gnats, moths, beetles, mosquitoes, flies and other creatures.

Bats are generally shy and secretive, and I consider it a special treat to watch their swooping flight at dusk. During the summer and fall, however, it is common to have a bat find its way into human homes and structures. If you have a bat flying around indoors, the best course of action is to “corner” the bat in a room where a window or door can be left open and let it find its own way out. If you need to gently pick up a bat, always wear gloves and release the bat as quickly as possible.

By winter, all Minnesota bats have moved to hibernation areas such as mine shafts or caves where they use stored fat to get through the long, insect-less winter. A new bat disease, known as White-Nose Syndrome, has killed millions of bats on the east coast and Appalachia, and while it has not yet been confirmed in Minnesota, it seems only a matter of time. Minnesota bats are important both ecologically and economically, eating literally tons of forest and agricultural pests each year. Biologists are working hard to find ways to control White Nose Syndrome, not only for the bats’ sake, but for our sake as well.

Join us for the following nature program. Reservations required, call 763-559-6700. Kites and Flight, Saturday, July 11, 10 a.m.-noon, ages 5+, $5.

Free Family Fundays: Come by on Sunday afternoons anytime between 1-3 p.m. for a free family program: Flying Free on July 5, Mississippi Scavenger Hunt on July 12, Under the Microscope on July 19, and Fishing on July 26. Reservations not required. Call us at 763-694-7693 for info or visit,