In the cool of the evening, hundreds of dangerous blood-sucking creatures – nature’s real-life vampires – fly out to prey upon humans. Fortunately, these pests are hunted by a very effective enemy: bats.
“One little brown bat can eat 7,000 mosquitoes every night. They’re the most common bat we have,” Sharon Peterson told both kids and adults in a presentation at Kendall Young Library in Webster City.
Peterson has been teaching people about bats since 1996 with her organization Incredible Bats. Though misconceptions about bats are common, and people don’t always appreciate them, bats are extremely helpful animals, Peterson said.
Not only are bats big mosquito eaters. Big brown bats, another common species in Iowa, devour crop pests like moths and beetles.
“It’s estimated that bats save us billions of dollars in pesticide usage every year,” Peterson said.
More specifically, the Pella Wildlife Center in Des Moines reports that bats’ estimated value to Iowa’s agricultural industry is $1.76 billion per year, or roughly $50 an acre.
Other researchers have estimated the nationwide agriculture value of bats at $22.9 billion a year, according to an April 1, 2011, article in Science Daily.
They’re not that bad
Peterson said she got into the bat education business because she heard so many people repeating myths about bats.
“The myth is a bat will attack you or get in your hair,” she said. “They don’t want to have anything to do with you. At the Congress Avenue bridge in downtown Austin, Texas, people come out to watch the bats. There are 1.5 million bats living under the bridge, and no one ever has been attacked.”
Bats aren’t blind, either, and they don’t suck blood. There are vampire bats, but these only live in South America. They lap up blood, and and they feed on livestock, not humans.
Bats also don’t cause harm to your home, she said, drawing a sharp contrast with rodents.
“Rodents want to get in your house to eat your food. They will chew through things, and do a lot of destruction in a home,” said Peterson. “When bats get inside, it’s going to come through an already existing hole. It will get inside just to be safe, warm and dry. It doesn’t want to eat anything in your house.”
Also, one breeding pair of mice could have thousands of offspring in a year’s time. Bats typically have only one baby per year.
Bats have a bad reputation as rabies carriers, but actually less than 1/2 of 1 percent of bats carry rabies, she said.
“It’s not so widespread as people make it out to be,” she said. “They’re not dirty. Bats are very clean animals. They lick themselves like a cat does.”
Bats, of course, should not be handled without heavy gloves.
Bat houses and other habitats
Beth Collins, a science instructor at Iowa Central Community College, said she doesn’t quite understand all the misconceptions either. It’s also weird, she said, that people think bats will get in their hair.
“They can sense where your hair is,” she said.
“Halloween doesn’t help either,” said Webster County Naturalist Karen Hansen.
Collins teamed up with the applied sciences class a few years ago and got some students to build bat boxes for the campus.
The boxes provide a place for bats to live, so they don’t get into the buildings.
“They need a place to roost, and if you don’t provide a place, then buildings work for them,” Collins said. “I was sitting in my office, and I saw something fly by the doorway. There was a bat in the building.”
She hasn’t seen any more of that since the boxes went up, Collins said. There are now seven bat boxes in trees throughout the campus.
The college found designs on the Internet, she said. The boxes have four slats inside to provide more surfaces for the bats to cling to, and the outsides are painted black.
Bat house plans can be found online from Bat Conservation International. The color of the box depends on the average high temperature in the area. Bats like temperatures of about 95-100 degrees Fahrenheit when they’re roosting.
“They have to be a certain distance off the ground, because when bats come out they just like to drop out of the box,” Collins said.
Hansen said bat boxes are pretty common around here, and Webster County Conservation can also provide plans.
Bats are protected under Iowa law. It’s illegal to kill bats except when they’re found in a building occupied by humans.
When a bat flies into your building, the best thing to do is just open a window, Hansen said. The bats will find their own way out.
Big brown bats and little brown bats are the most common bats around people, Hansen said. Big brown bats especially like to hibernate in this area if they can find a warm place to stay.
To deal with bats living in a house or attic, first find where they are coming in, Hansen said. This can be difficult because bats can squeeze through tiny cracks.
“If people do have bats, I recommend first of all they wait until they see the bats leave,” she said. “Then you can put a flap of screen over top of the hole they’re entering from, and then they can’t get back in, but any other bats can still get out.”
This must be done in late July or August at the earliest, though, because before then the baby bats haven’t learned to fly yet and will remain in the roost while the mothers are away feeding.
“You can’t seal up your problem area and seal the babies inside. They’ll starve to death,” she said.
Nine species of bats live in Iowa.
Big brown and little brown bats look very similar; size is the main difference. Little browns are about 3 inches long with up to an 11 inch wingspan. Big browns are 3 to 5 inches long with up to a 15 inch wingspan. They also have slightly longer noses.
The Indiana Bat is the only bat in Iowa on the Federal Endangered Species list. They are dull grey to brown and less than 3.5 inches long.
Both silver-haired bats and hoary bats roost on bark. The hoary bat is the largest bat in Iowa, about 5 or 6 inches long.
The smallest bat in Iowa is the pipistrelle, or tri-colored bat. They have an up to 10-inch wingspan.
“A Guide to Bats in Iowa,” Iowa DNR.