How To Help Bats Taking A Dip In Our Backyard Pools

Just A Sip

A greater mouse-eared bat, M. myotis, closing in on a water surface, opening its mouth and lowering the head to take a mouthful of water.Photo by Dietmar Nill/via Nature Communications

Your backyard pool is much more than a nice urban oasis for you, your friends and your cold drinks (you lucky duck). It’s also a pit stop for animals, which need a quick drink or a cooling dip just as much as we do. But sometimes pools can be dangerous for them.

Bats, for instance, don’t stop to take a drink. Echolocating bats emit high-frequency signals to find water, and then they swoop down toward the surface, dipping their heads and opening their tiny mouths to take a gulp. This usually happens in one fluid motion, and they take off just as quickly as they dive. They need solid surfaces to take off, so they can't land in the water, take a drink and take off again.

"So if there's an obstruction in the way or the pool is too small or something goes wrong, they can get trapped in the pool and die," explains researcher Zachary Nickerson, a student at the Center for Bat Research, Outreach, and Conservation at Indiana State University.

Joy O’Keefe, assistant professor of biology at Indiana State and director of the Bat Center, last year started hearing reports about dead bats in swimming pools around the midwest. She wanted to confirm the anecdotes, so she put together a survey. She found 78 percent of the people who responded found bats near their pools. About 13 percent found bats that had drowned.

Why would a bat drown? Although they don't alight to drink, they can swim. Bats that eat frogs might swim from shallow pond water onto a shoreline, crawl out and fly away. The problem is that most pools have fairly high walls, and bats can't use metal handlebars to climb out like we can. Without a solid surface to launch from, they get stuck and drown.

With enough evidence that this is a problem, conservationists could start recommending pool owners make a couple simple tweaks to help out the animals. Small ramps — like the kind you can already buy to help your dog out of the pool — could be enough to save a bat's life.

This year's survey is under way. If you're one of the lucky ones with a pool on your property, go here to fill it out.