Wonders of Creation

•Bats are a fascinating group of animals. They are one of the few mammals that can use sound to navigate--a trick called echolocation.

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•Of the 1300 species of bats, more than half rely on echolocation to detect obstacles in flight, find their way into roosts and forage for food.

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•Echolocation--the active use of sonar along with special physical features and physiological adaptations--allows bats to "see" with sound.

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•People like Richard Dawkins use the bat to support evolution.  In his book “the blind watchmaker” he uses the bat to support his view that we evolved. 

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•His idea is that some bats don’t use echolocation and some do so this for him supports evolution by adaptation.  He is right that some use echo location and some don’t.  That is all I will give him.

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•It is all about volume.  Loudness!

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•Echolocation calls range in frequency from 20 to 200 kilohertz (kHz), whereas human hearing normally tops out at around 20 kHz.

•These noises resemble the sounds made by hitting two round pebbles together.

•Bats emit calls as low as 50 dB and as high as 120 dB, which is louder than a smoke detector 10 centimetres from your ear.

•That's not just loud, but damaging to hearing.

Deafness is a major concern here as without echolocation they cannot eat or avoid obstacles.  They would die.  What is the solution as they are clearly alive and well.  1300 different types of bat!

Very sensitive hearing Horseshoe bats can detect differences as slight as .000l Khz. 
For bats to listen to the echoes of their original emissions and not be temporarily deafened by the intensity of their own calls, the middle ear muscle (called the stapedius) contracts to separate the three bones there--the malleus, incus and stapes, or hammer, anvil and stirrup--and reduce the hearing sensitivity.

 

 •Bats are able to yell without damaging their own hearing only to a special adaptation that actually causes them to go deaf just before a call is emitted- the muscles in the middle ear actually pull apart the hammer, anvil, and stirrup bones so that sound can’t travel to the cochlea. The muscles relax to allow the bones to reconnect as the sound echoes back.

•The ossicles- ear bones- comprise the hammer, anvil, and stirrup, which are pulled apart by a muscle contraction to prevent the bat going deaf from its own screams.

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•This contraction occurs about 6 ms before the larynx muscles begins to contract. The middle ear muscle relaxes 2 to 8 ms later. At this point, the ear is ready to receive the echo of an insect one met

•We have a little biomimicry today with the sonar bats use copied in many ways in our modern world, such as the echo location system on a submarine.  Same system just in water.

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•We have a stunning system of echo location that is so accurate they don’t fly into things and can find food to eat.

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•The ear separates at just the right moment for just the right amount of time so the Bat doesn’t go deaf.  Fearfully and wonderfully made.

er away, which takes only 6 ms.

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