Friday, March 28, 2008


Nature Watch
August 13, 2008

By Susan Benson,
CNHM Director of Education

While sitting out on a pleasant summer night, you might hear the whisper of wings or catch a glimpse of small dark objects careening through the sky. To many, the fleeting sight of a bat evokes a range of fears, most of which are unfounded.

Bats are the only flying mammals – in fact, the 950 different species of bats worldwide represent about 20 percent of all the planet’s mammal species. As with other mammals, bats nurse their young on milk. Bats also are quite clean; they groom themselves frequently, much as a cat does.

“Eek! They want to get caught in my hair, or suck my blood” is a common misconception. Only three bat species eat blood, and only very rarely is that human blood. The two main groups of bats include the “mega-bats,” or fruit bats, that eat fruit, nectar and pollen. The larger group of “micro-bats” eats insects. They navigate and hunt by a system called echolocation, whereby they emit sound waves that bounce off of objects and return as an echo, allowing the bat to fly about safety and locate prey. Wisconsin is home to seven bat species, all of them insect eaters.

On warm summer nights, you might consider the little brown bat, a Wisconsin native, an ally because it can catch and consume up to 600 mosquitoes per hour. Little brown bats (Myotis lucifugus) are the most common Myotis species in the northern two-thirds of the United States. Often found in tree hollows and buildings during the summer, it can roost with big brown bats. It is most likely found near water sources. In winter, it hibernates. The big brown bat is another common and widespread species of bats throughout North America. It roosts in colonies in tree hollows and buildings. As it is more tolerant of cold conditions than other resident bats, it is the only one that overwinters in walls and attics.
Bats cause humans little harm, especially compared to the disturbances they’ve suffered as a result of human activity. Many bats die from eating contaminated insects. Fear and ignorance have led to bat eradication campaigns by individuals and even governments. Some logging, development and agricultural practices can drastically reduce bats’ natural habitat.

Bats may find their way into buildings, looking for safe roosting habitat. If a bat should get into your home, open a window or door and allow it to find its own way out. If it cannot, wait until it has landed, then using a glove or towel, gently catch the bat and release it outside. The best way to remove roosting bats from attics or other areas is to find and seal their entry points after they have left for nightly feeding or in the fall after they have migrated.

Nature Watch is brought to you by the Cable Natural History Museum. For 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility in Cable at 43570 Kavanaugh Street or on the web at to learn more about exhibits and programs.