Bats are world-class echolocators, capable of navigating tight spaces and detecting minuscule insects. Photo: iStock / ivkuzmin

Bats are world-class echolocators, capable of navigating tight spaces and detecting minuscule insects. But smooth manmade structures can foil their sonar, a study published today in Science finds, potentially causing fatal collisions.

Why it matters: Bats are voracious eaters of insects, including many agricultural pests. They play a key role in keeping bug populations down. But urban noise pollution, habitat loss, pesticide use, wind farms and a fungal disease are causing bat populations to plummet. This study could explain why dead bats are frequently found near buildings.

What they did: Scientists at the Max Planck Institute for Ornithology created a rectangular flight tunnel, and placed a two metal plates in the tunnel, one vertically against the wall and one on the floor. Of the 21 greater mouse-eared bats flown in the tunnel, 19 touched the vertical plate at least once. None of the bats touched any other part of the tunnel. Then the scientists placed vertical plates near real bat colonies — and the wild bats crashed into them, too.

What's happening: The researchers think that the unnaturally smooth manmade surfaces reflect sound in a way that makes them almost undetectable. A bumpy surface would scatter sound in a way the bats could use. A smooth surface can redirect it away from the bats' ears, rendering the structure auditorily invisible.

Go deeper

Justice Department sues Google over alleged search monopoly

Illustration: Lazaro Gamio/Axios

The Justice Department and 11 states Tuesday filed an antitrust lawsuit against Google, accusing the company of using anticompetitive tactics to illegally monopolize the online search and search advertising markets.

Why it matters: The long-awaited suit is Washington's first major blow against the tech giants that many on both the right and left argue have grown too large and powerful. Still, this is just step one in what could be a lengthy and messy court battle.

Updated 2 hours ago - Politics & Policy

Coronavirus dashboard

Illustration: Aïda Amer/Axios

  1. Politics: Americans feel Trump's sickness makes him harder to trustFlorida breaks record for in-person early voting.
  2. Health: The next wave is gaining steam.
  3. Education: Schools haven't become hotspots.
  4. World: Ireland moving back into lockdown — Argentina becomes 5th country to report 5 million infections.

In photos: Florida breaks record for in-person early voting

Voters wait in line at John F. Kennedy Public Library in Hialeah, Florida on Oct. 19. Photo: Eva Marie Uzcategui/AFP via Getty Images

More Floridians cast early ballots for the 2020 election on Monday than in the first day of in-person early voting in 2016, shattering the previous record by over 50,000 votes, Politico reports.

The big picture: Voters have already cast over 31 million ballots in early voting states as of Tuesday, per the U.S. Elections Project database by Michael McDonald, an elections expert at the University of Florida.

Get Axios AM in your inbox

Catch up on coronavirus stories and special reports, curated by Mike Allen everyday

Please enter a valid email.

Subscription failed
Thank you for subscribing!