Bats emit sounds at typically 2 or 3 times higher pitch than we can hear. Sounds above human hearing are usually called ultrasonic. Whales and elephants can make sounds below what we can hear, about 16Hz (16 cycles per second), and these are called infrasonic.
http://teachertech.rice.edu/Participants/cllamas/lessons/science/bats/batsounds.htm
3 Signs You Can Spot Before Hearing Bats. Before hearing the tell tale squeaks and scratching noises bats can make, there are three things you can spot beforehand. Bats flying around outside your home – It is perfectly normal and natural to see bats flying around outside at night foraging for food and water.
https://www.getbatsout.com/bat-sounds-hearing-is-believing/
Bats tend to be very quiet mammals. They are nocturnal but leave their roost at night to feed. You will probably only hear bats if they are living in your walls and they get disturbed by a slamming door or some other loud noise. Bats make small squeaking noises and you may hear them crawling (sounds like scratching) at dusk and dawn when they are waking or returning to the roost.
https://www.getbatsout.com/3-signs-bats-living-home/
Before hearing the tell tale squeaks and scratching noises bats can make, there are three things you can spot beforehand. 1  Bats flying around outside your home – It is perfectly normal and natural to see bats flying around outside at night foraging for food and water.
https://www.getbatsout.com/bat-sounds-hearing-is-believing/
The bat sounds in this column are collected from the web and are generally available to everyone for personal use. PIR did not create these city sounds and cannot grant absolute permission for any use other than personal. Please do not direct link to these sounds.
https://www.partnersinrhyme.com/soundfx/batsounds.shtml
These high quality bat sounds are for multimedia producers who need permission to use the audio included in their projects. The sounds in this category are royalty free and available for immediate download as high quality stereo WAV files.
https://www.partnersinrhyme.com/soundfx/batsounds.shtml
In the bat detector we have there are two ways to make the sound audible:-. 1  Heterodyning - mixing the sound from the bat with a steady ultrasonic frequency of similar frequency. If you get the steady frequency right the two notes beat with each other and produce an audible sound.
http://teachertech.rice.edu/Participants/cllamas/lessons/science/bats/batsounds.htm
Believe it or not, bats are actually very quiet animals. Most people do not know they have a colony of bats living in their attic until they see signs of guano scattered about their home or have one accidentally wind up in their living room. Bat sounds are indicative of a larger scale problem.
https://www.getbatsout.com/bat-sounds-hearing-is-believing/
It’s Time for a Bat Watch! If you notice any of these three things, it’s time for a bat watch. At sunset, take a lawn chair outside, sit down, and look up at your house. Just sit back and watch for bats leaving their roost for the night. If you do have bats in your house that’s one way you may see them.
https://www.getbatsout.com/3-signs-bats-living-home/
The answer is the Bat Detector, an electronic box that has an special ultrasonic microphone (ordinary microphones only just manage the human range of sound) and electronics to make the sound audible. The recordings below were all made on warm evenings at dusk in April 1998.
http://teachertech.rice.edu/Participants/cllamas/lessons/science/bats/batsounds.htm
what noise bat makes
Bats make small squeaking noises and you may hear them crawling at dusk and dawn when they are waking or returning to the roost. The noise that bats make are small squeaking noises and scratching sounds.