SO: v8 (Second Timers)

WILD COCHLEAS:  Bats can be in a cave with a million other bats and not get overwhelmed with the sonar of other bats screaming at them from every direction.  This is quite incredible.  This means that they must have the ability to discriminate between their sonar blasts and others must faster than in thousandths of a second.  THINK!

WILD COCHLEAS: Kids can hear sounds that vibrate 20,000 times a second. That’s 20,000 Hz. Hz stands for hertz. A hertz is 1 vibration a second. Older folks have trouble with high sounds over 18,000 Hz, but do well with sounds lower than that. Most people hear low sounds down to 20x/second or 20 hertz.

WILD COCHLEAS:  Whales detect sounds too low for us to hear…5-8 vibrations a second.  Dolphins hear sounds over 100,000 Hz.  Some bats top an amazing 180-212,000 hz. That’s 180,000-212,000 vibrations a second!

WILD COCHLEAS:  The wide front of the inside of the coiled snail-shaped cochlea has stiff hairs.  These detect low sounds like the booming of a bass drum. The tight coil in the center has floppier hairs.  These detect high sounds like the notes of a piccolo.

WILD COCHLEAS: Animals, such as elephants and whales hear infrasound-–sound lower than we can hear. The outer coil of their cochlea is 9x wider than the inner coil. Animals–like cats–that can only hear down to 55 Hz have outer coils that are only 6x wider than the inner coil. Scientists discovered that animals with tightly coiled cochlea have greater hearing ranges.

WILD COCHLEAS:  The ability to hear very high sound in dolphins and bats is accomplished by stiffer hairs in the front of the inside of the cochlea and a thin springy membrane in the center of it.

WILD COCHLEAS:  With their incredible DNA-designed cochlea, bats, like the horseshoe bat, can distinguish sounds that are 1/10 of vibration less than another’s when vibrating 180,000 times a second. This is how they can tell their sonar from thousands of other bat’s sonar and keep from crashing into one another when sonar blasts are being beamed everywhere in caves and in dense forests.

WHALE SOUNDS:   Whales are masters of LOUD sound transmission– ridiculously loud sounds!  And boy can they hit the distance records with their sounds!

The bigger-than-the-dinosaurs blue whales send out intensely loud sounds.They can hit 170 decibels!  Jet engines reach just 140 decibels and the shuttle launching barely tops 200 decibels!  (This means they are considerably louder than a jet engine.)

When they point their heads down and blast with this intense sonar, they’re scanning the ocean bottom for giant squids four miles down.

WHALE SOUNDS:   Whales in the waters off New York use their insanely loud sounds and communicate with whales all the way across the Atlantic Ocean off the shores of Britain!

WHALE SOUNDS:   In WW2 we learned that there was a section of the ocean at 3000 feet that’s now named the SOFAR channel. It transmits sound amazingly.  In WW2, subs headed down to this depth to send long range sonar transmissions only to find humpback whales already there relaxing and blasting messages to kin hundreds and thousands of miles away!