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April 6, 2017

Did You Know? Twelve Fun Hearing Facts

My daughter recently turned 11 and is at that age where half of her friends have cell phones and the other half want them. So, my husband and I compromised and gave her my old cellphone. This way she has a camera and the ability to download apps without having the ability to call and text. She was thrilled with this as for her it really was all about the apps. One of her favorites is Trivia Crack. My daughter and I, her friends, and grandparents love playing this one. I can’t tell you how much time I have wasted seeing how many random facts I know and learning new and sometimes useless facts. Which lead me to today’s blog. So, for all of you out there craving random knowledge or just looking to be entertainment here it is. Random facts about ears and hearing! I hope you enjoy reading these as much as I did researching them.

Did you know… Dogs can hear much higher frequencies than humans. Depending on the breed and age of a dog they can reportedly hear up to 45,000Hz or in some breeds even 60,000Hz. Humans on the other hand can only hear up to 20,000Hz. But if you are reading this blog you probably are not hearing sounds at 20,000Hz as you start to lose hearing in the ultra-high frequencies starting in your 20s and 30s. If that doesn’t impress you maybe bats will. They can hear up to 100,000Hz.

Did you know… animals hear better than humans. I’m not just talking about frequency as we did just cover that. But they can also hear softer sounds than we can. Parrots’ hearing is so extraordinary that during WWI they were kept on top the Eiffel Tower in Paris, France to warn people of approaching enemy aircraft. The parrots were trained to squawk whenever a plane was approaching, which they could hear from 20 miles away.  Unfortunately, the parrots were not able to tell the difference between enemy and allied aircraft so this practice was eventually discontinued.

Did you know… the ears of a cricket are located on their front legs just below the knees. Crickets do not actually hear sound but rather sense vibration through tympanal organs on their legs. This consists of a membrane called a tympanum and a chordotonal organ which receives these vibrations. This system is very sensitive to vibrations and able to distinguish different chirps to know whether it is a mating call, a warning for other males to stay away or an alert of danger nearby.

Did you know… Cicadas have their hearing organs in their stomachs? The hum generated by a swarm of cicadas can reach 85 decibels. A level loud enough to send birds flying away as the sound is painful to their ears and actually interferes with their communication. Not only is this level too loud for birds but also for the cicadas. Cicadas have a membrane called a tympana which is connected to their auditory organ by a tendon. When a male sings, the tendon retracts creasing the tympana which in turn dampens the sounds and protects the cicadas ear.

Did you know… Mosquitoes have a two-feathery antenna on their head that give them a highly-developed sense of hearing. Male mosquitoes are specifically tuned to frequencies between 300 and 400 Hz which is the flight tone of female mosquitoes. Despite how annoying mosquitoes are they do have one positive attribute which is they are quiet unlike the cicadas. Actually, if you are over the age of 25 you will have lost enough hearing already to not hear the mosquitoes buzz. So, you won’t even know they are their until you feel their sting. Ouch!

Did you know… Snakes hear through vibration of their jaw bone which is connected to their inner ear.

Did you know… Fish do not have ears! Well not external ears anyway. Fish only have inner ears consisting of 3 otoliths or ear stones that lightly rest on nerve hairs. Depending on the size of the fish these otoliths can be the size of a grain of sand or in the case of a large fish as big as a marble. So how do fish hear? Pressure changes through the ridges of their bodies send vibrations through the fish moving the otoliths. This movement in turn moves the nerve hairs sending signals to the brain so the fish knows what is happening around it.

Did you know… sound travels at 700 mph. The only thing faster is light which travels at 671 million miles per second.

Did you know… The African elephant has the largest ears of any other animal. Their ears are about a 1/6 of the size of their body. Elephants have good hearing but their ears are used for more than just funneling sound into the ear canal, they are also a cooling mechanism. The skin on elephant ear is very thin and full of blood vessels.  So as the blood circulates through the ears it cools off before circulating back into the body. For this reason, the size of an elephants’ ears are dependent on where they live. The African Elephant is near the equator so it has the largest ears whereas the woolly mammoth lived in the arctic and had small ears as it needed to retain as much body heat as possible. Which may seem irrelevant since the woolly mammoth has been extinct for about 4,000 years but scientist are attempting to bring this beast back through genetic engineering. It’s true. Google it if you don’t believe me.

Did you know… a giraffe can clean its ears with its 21-inch tongue? I really have no more to say about this. I mean just because you can do something doesn’t mean you should.

Did you know… the smallest bones in the body are the ossicles located in the middle ear. There are three ossicles known as the malleus, incus, and stapes. The malleus is the largest of the ossicles with an average size of 8mm while the stapes, the smallest of the ossicles, is just 2.8mm. To help you picture this a little better all 3 bones can fit on a dime and still have room to spare. However, despite their minute size these ossicles have a big job. The ossicles work together as a lever taking the acoustic vibration of the eardrum and converting it to fluid pressure in the cochlea. Basically, amplifying and transmitting the sound so we can hear. But that is not all. Thanks to the help of the stapedian muscle the middle ear bones will stiffen to sudden loud sounds working to dampen sound and protect our ears. However, the stapedian reflex is just that a reflex…it cannot maintain this retraction for long periods of time.

Did you know…Those great seats you secured in front of a speaker at a rock or pop concert are exposing you to about 120 decibels? That is loud enough to damage your hearing in the first 8 minutes! Your stapedian muscle cannot help you here. Entertainment aside, this last auditory fact comes with serious consequences. If you or a family member are planning to attend a concert this summer pick up a set of earplug or better yet contact me to be fit with custom-made musician plugs.

I’d love to continue to entertain you with more auditory tidbits but I’m sure you have other things to do today so I will end it here. I hope you found this blog to be entertaining and are leaving with a little more knowledge then when you started. If you know of anyone who enjoys random facts or loves attending concerts make sure to pass this blog onto them.