Why Bats Crash Into Windows (nature.com)

According to a new report published in the journal Science, Bats slam into vertical structures such as steel and glass buildings because they appear invisible to bats' echolocation system. Nature reports: Bats rely on echolocation to navigate in the dark. They locate and identify objects by sending out shrill calls and listening to the echoes that bounce back. Greif and his colleagues tested the echolocation of 21 wild-caught greater mouse-eared bats (Myotis myotis) in the lab. The researchers placed a featureless metal plate on a side wall at the end of a flight tunnel. The bats interpreted the smooth surface -- but not the adjacent, felt-covered walls -- as a clear flight path. Over an an average of around 20 trials for each bat, 19 of them crashed into the panel at least once. The researchers also put up smooth, vertical plates near wild bat colonies, and saw similar results. The animals became confused owing to a property of smooth surfaces called "acoustic mirroring." Whereas rough objects bounce some echoes back towards the bat, says Greif, a smooth surface reflects all echolocation calls away from the source. This makes a smooth wall appear as empty space to the bats, until they are directly in front of it. Only once a bat is facing the surface are their perpendicular echoes reflected back, which alerts the bat to its mistake. This explains why some bats attempted to swerve out of harm's way at the last second -- but often too late.

Comments

Because Windows is full of bugs?

[chuckugly]

It had to be done.

Re:Stupid Windows

[Tablizer]

Yes, crashing Windows does drive me bats.

stealth uses this same function

[turkeydance]

to disturb the accurate reflections of enemy radar

Re: stealth uses this same function

[Immerman]

The tighter the curvature, the more likely some portion of the surface will be pointed towards the bat, and thus generate a return signal for them to hear.

Think of it like firing an air-cannon of tennis balls in front of you in the dark (while deaf) - if the expanding cone of tennis balls hits a smooth wall at anything other than almost dead on, all the balls will bounce away from you. On the other hand, if there's any substantial curvature to the wall then some of the balls will probably bounce back at you. When you get hit by the returning balls, you know there's something in front of you,

Re: stealth uses this same function

[amicusNYCL]

I think this is just an excuse for the researchers to be dicks.

"There's a wild bat colony near my house. Let's put up some glass panels and some cameras."

Only in soviet Russia

[GuB-42]

In soviet Russia windows make bats crash.
In capitalist America, .bat make Windows crash.

Birds also crash into large glass walls

[Gabest]

Even I hit a very clean glass wall once, thinking it was the exit.

Re:Birds also crash into large glass walls

[blindseer]

On the farm as a kid I wondered why there were all these pigeon feathers in front of the large ventilation fan in the wall of the barn. It was a very large fan, something like 3 feet across, and had very little for a protective mesh. My questions were answered one day when I opened up the barn door and startled a pigeon that got in the barn somehow. It took off for the running fan and... feathers everywhere. I realized why I never saw a dead pigeon when I saw one of the barn cats wander over to look for meat.

Also while living on the farm we'd hear the birds "thud" against the walls of the sheds, barn, and house. Turns out that birds run into things, even bright red sheet metal siding. Once in a great while we'll see the dead birds lying on the ground from hitting the walls before the cats found them. The cats did well in cleaning up that mess though, they'd find them eventually.

Re:Birds also crash into large glass walls

[wickerprints]

Indeed. And the underlying physical principle is similar, except instead of sound waves in the case of bats, it is light waves in the case of birds. For example, if the sky is reflected in glass, a bird can fail to see the obstacle.

Few natural structures exhibit the kind of macroscopic reflectivity of man-made walls or glass windows. Bats and birds did not evolve sensory mechanisms to avoid collisions with these.

Re: OMG

[lucm]

Let's see how many comments on this story will NOT be jokes about Microsoft Windows or Batman

But bats are endangered and we can do something

[bussdriver]

Many birds have gone extinct because of us and we didn't know or if we did we didn't do anything; besides, we have lots of tiny birds and losing multiple species of tiny birds because of our house cats. We don't have tons of bats and they have a different job-- a better job: eating annoying bugs.

Re:But bats are endangered and we can do something

[Hognoxious]

I was just thinking about house-martens and barn owls. Where did they live before humans?

Re:But bats are endangered and we can do something

[Anonymous Coward]

With their relatives.

Is this humane?

[Plus1Entropy]

Watching the video I feel bad for the bat...

Re: Are bats really blind?

[RightwingNutjob]

Bats tend to use very high frequencies (100kHz+ = 3mm wavelength). Humans do most of their talking and hearing below 2 kHz = 15 cm wavelength. At the 15cm level, glass and a brick wall are both featureless and flat reflectors. At the 3mm level, glass is a lot smoother than a brick wall.

Re: OMG

[s1d3track3D]

I don’t know,

Q: Why did the bat crash into windows?
A: It saw the Blue Screen of Death

Q: Why did the bat crash into windows?
A: Because the door was closed

Q: Why did the bat crash into windows?
A: Because the Mac was more secure

Q: Why did the bat crash into windows?
A: Because it ran l33t c0d3z scr1ptz

Q: Why did the bat crash into windows?
A: Because the batman is a master technologist

Your welcome!

(thank you, i’ll be here all night)

Re: OMG

[war4peace]

My welcome is stronger than your welcome!

Re: OMG

[s1d3track3D]

Heh, I see what you did there.
Just remember your windows need to be stronger than the windblows...

Re: Are bats really blind?

[Sique]

The problem is not the echo-ability as such, but the direction of the echo.

With a smooth surface, you have the elementary law of reflection: incoming angle equals outgoing angle. That means that only the sound wave that hits the glass plane at exactly 90 degrees will be reflected back into the direction it came from. Thus only the bats flying straight to the glass window will detect it with echo-location. Any bat flying in an arbitrary angle to the plane will not hear the echo, as it is directed away from the bat.

A brick wall has lots of different angles, and the probability is very high that at least some part of the brick wall will reflect the echo back to the source.

Basicly this is the same effect stealth technology uses to make objects invisible to radar: plane surfaces will not reflect anything back to the source except for the quite improbable case to be hit directly at a 90 degree angle.

that's evil

[Cederic]

The researchers also put up smooth, vertical plates near wild bat colonies

The bastards!

It's easy

[The123king]

@echo off
:crash
start
goto crash

Save that as a .bat, then run as administrator. Anyone can make a bat crash Windows!

Re: OMG

[zapez.perplex]

they will no longer crash in Windows 10 SP1