What's the connection between nautical physics and snakes?
According to the Discovery web site, researchers in the U.S. and Germany employed the physics of bobbing boats to determine that snakes don't have one hearing system, they have two distinct auditory systems.
For many years scientists did not think snakes could hear due to the lack of external ears and ear drums. Now scientists have shown despite the lack of external ears and ear drums, snakes can in fact hear.
It's all in vibrations.
It's amazing how little we know about the biology of snakes, stated Bruce Young, a biology professor at Washburn University and an author of the study.
For many years, scientists believed that snakes couldn't hear. Herpetologists (researchers who study reptiles) believed snakes gathered information about lunch and their surroundings through smell, taste and special heat-sensing organs near the nose.
Rudimentary experiments in the 1970's indicated that snakes could, indeed, hear but researchers couldn't pinpoint exactly how.
Well, scientists have finally determined how by using boat physics. Yep, boats. The lower jaw of the snake is essentially a rigid cylinder, Bruce Young explained. So, in that respect, its not that different from a ship [also a rigid cylinder].
Researchers used the exact algorithms (math formulas) that measure a ship's movement in water to model a snake's jaw as it moves through sand or below ground. A ship can move in six different directions called heave, roll, yaw, pitch, etc. And a snake's jaw moves in precisely those same directions.
When sound vibrations are picked up through the snakes jawbone, they travel to a cochlear mechanism within the snakes auditory system and there, those sound vibrations are converted to electrical impulses and transmitted to the brain. That's how the snake knows that a mouse, aka lunch, is tip-toeing behind that sage brush.
The result? Snakes hear through the jaw bone and through a traditional inner ear. In essence, snakes have two, distinct hearing mechanisms. In fact, researchers believe snakes can hear in stereo. Their jaw moves independently on each side, thus each side of the jaw transmits sounds to two different cochlear mechanisms.
It's called bone conductive hearing
and it occurs in snakes and humans, though to a lesser degree in humans since we aren't homing in on mice for a snack.
With traditional hearing, sounds create disturbances in the air which are picked up by the ear cup, directed down the ear canal bouncing off the ear drum, stimulating three tiny bones which, in turn, vibrate the cochlea, a tiny snail-shaped mechanism that's lined with millions of tiny hair-like projections floating in cochlear fluid. These hairs pick up the vibrations of the cochlear fluid, convert analog (sound wave) information to electrical impulses that are then sent to the brain for analysis by you and by the black mamba (the deadliest snake in the world, but they hear pretty well).
For some humans the conductive part of their hearing (outer and middle ear) is not always present or functional (see causes below); however their inner ear and nerves are working normally. Certain diseases or anomalies may cause a human to be born with the outer portion of the ear absent or the ear canal may be so narrow that sound is unable to make its way down to the eardrum.
So if they are missing the first part of the hearing process, with the second part the nerve intact, how can they hear and what sorts of solutions exist for them?
Like reptiles, we also hear through our bones using the process of bone conductivity. Bone conductivity allows bypassing the outer and middle parts of our hearing process and directly stimulates the cochlea.
Technology improves bone conduction hearing in humans
Cochlear Americas, a leading designer and manufacturer of implantable hearing devices, manufacturers an implantable hearing device that uses direct bone conduction of sound waves to stimulate the hearing nerves delivering electrical impulses to the auditory centers of the brain.
Called the Baha System, the device is designed for people with conductive and mixed hearing loss. The Baha creates a path that bypasses outer and middle ear damage, delivering sound vibrations directly to the cochlea for processing and conversion to electrical impulses.
The unit doesn't employ sound amplification technology like traditional hearing aids. Instead, the device enhances the natural transmission of sound through bone conductive hearing.
The Implantation Procedure
It's minor surgery, during which a titanium implant is placed in the skull behind the ear, specifically the mastoid bone. It takes a few months for man and machine to fully connect up by a process known as osseointegration, and no, you don't have to know that for the test.
After this process, in 60 to 90 days the device is hooked up and conductive hearing is improved immediately. This system has been in use since 1996, is fully FDA cleared and has helped more than 25,000 men, women and children enjoy a higher quality of life.
Is this the solution for you?
According to Cochlear Americas, the BAHA is for persons with conductive hearing loss, mixed hearing loss or single sided deafness. Causes of these hearing losses may be congenital (present at birth) or acquired at some point through out life. Causes may include:
- Malformation of the ear canal or middle ear
- Infection of the ear canal resulting in chronic draining ears
- Chronic otitis media
- Congenital atresia
- Middle ear dysfunction/disease
- External otitis
If you have suffered from conductive and mixed hearing loss for many years and are unable to benefit from traditional hearing aids, there is only one way to find out if you are a candidate.
Make an appointment with a hearing healthcare professional and have your hearing evaluated.
Hear better, snake style, with a bone conduction hearing device.