Bats are nocturnal animals, meaning they are mostly active at night.
We humans are diurnal animals, meaning we are mostly active during the day.
Both bats and humans have the same five senses, but, because we are active at different times, we don’t use them all the same way.
If someone throws a kickball at you in the daytime, only one of your five senses is going to prevent it from hitting you in the face. You can’t taste or smell how far away a kickball is. You can’t hear one coming toward you either. You may feel the kickball when it bounces off your head, but you won’t feel it before that happens.
We use our sense of sight to avoid hurtling kickballs. Our eyes work with our brain to turn light into pictures. This gives us a 3D map of what is around us.
If someone throws a kickball at you in the middle of the woods on a cloudy night, you won’t be able to see it coming. There is not enough light. No light, no sight.
If someone throws a kickball at a bat during the day, it will also use its sense of sight to tell how far away the ball is and get out of its way.
But, if someone throws a kickball at a bat at night, it won’t be able to see the kickball coming toward it either. They also can’t see without light. Unlike us, though, a bat will know to get out of the kickball’s way. This is because at night, bats get a 3D map of their surroundings using sound.
Like dolphins, bats “see” using echolocation. Echolocation allows animals to tell what is around them by listening to echoes. It works because sound travels from its source as invisible waves through the air.
Sound waves can travel through air, but they bounce off of anything that is solid. That is how you get an echo. If you’ve ever been in your school gym when your P.E. teacher wasn’t there and you started yelling something because you wanted to hear an echo (a popular and creative way to hear an echo of your voice is to yell the word “Echo!”), what happened was the sound waves that traveled out of your mouth bounced off the gym walls and then came back to your ears.
The echoes bats hear are the sound of their own voices. The bats create these echoes by being really, really noisy all the time.
This video isn’t 100% how bats actually sound. One reason it’s a little misleading is because bats are really loud. They constantly make noise at about 120 to 160 decibels. That makes each bat about as loud as being in the front row at a Motorhead concert.
The reason that bats, unlike Motorhead, have never given you tinnitus is because bats make sounds at a higher frequency than we can hear (just like a dog whistle does). A bunch of bats could be flying over you each as loud as Lemmy Kilmister and you would have no idea. (The reason you could listen to bat sounds in the video above is because the sounds were slowed down to a frequency that is in our hearing range.)
Another reason bats are also able to do echolocation is because they have really big ears. The parts of their (and our) ears that stick out are basically like catcher’s mitts for sound. The bigger the outer ears, the more sound waves they catch.
Sound waves bounce off the outer ear into the inner ear, where they get turned into information the brain can hear. Bats have amazing brains when it comes to processing sound waves. Depending on how long it takes the sounds they make to bounce back to their ears, they can figure out where the objects are around them and create a 3D map of their surroundings. They can tell where the tree branches are around them based on the echoes so they don’t fly into them.
Bats come out at night, because they are on a mission to find food. Most bats eat small insects, like moths and mosquitoes. The reason bats don’t have deep voices like Barry White is because the deeper a sound is, the lower the frequency and the bigger the sound’s wavelength will be. If the sound wavelengths are too big, they are likely to go right around the tiny insects they are looking for.
Bats make high frequency sounds with tiny wavelengths because those wavelengths are guaranteed to hit a mosquito and echo back. When a bat is hunting, they make about ten high-pitched chirps a second. This is basically like radar, just seeing what is out there. When their brain hears echoes that sound like the body of a mosquito, the bat begins chirping at much faster rate, up to 200 chirps per second. The rapid chirps keep echoing off the mosquito allowing the bat to pinpoint exactly where the mosquito is. The bat can then grab and eat the mosquito in midair.
Bats freak some people out (that’s why Batman became Bat-man, instead of say, Hummingbird-man), but they are actually amazing animals with incredible adaptations, like echolocation. They’re an animal that should become your new best friend. Unless, of course, you really like being bitten by mosquitoes.
To learn more about bats, read my book A Day in a Forested Wetland.
Online references and resources
Current Biology. “Echolocation.”
Field Museum. “Do All Bats Echolocate?”
In Our Time podcast. “Echolocation.”
National Parks Service. “Bats: Echolocation.”
National Science Foundation. “Batlab studies echolocation to learn how animals "see" with sound.”
Scientific American. “How do bats echolocate and how are they adapted to this activity?”
Smithsonian Magazine. “Here's What Bat Echolocation Sounds Like, Slowed Down.”
STAC Climate Control. “Noise Levels dBA/Decibels.”
Weizmann Institute of Science. “Echolocation in Bats.”
Photos and Images
Click the photos and images used above to find their sources. If it isn’t linked to anything, than Kevin Kurtz or Sarah Zakalik must have taken it.