Having recently undergone a period of hearing loss due to a blown-out eardrum – a long (and disappointingly boring) story that I’ll save for another time – I got to thinking about the wonderful world of sound and what a wild thing hearing actually is. A sound is a form of energy that travels via vibrations in matter, such as air, water, or solids. When an object vibrates, it creates pressure waves in the surrounding medium, which propagate outwards as sound waves. So hearing is actually just a really highly refined sense of touch. Science!
Sound is one of the five ways that most living organisms can physically interact with the world around them, and for many creatures out here, it is arguably the most important. Ok, the sense of sight likely takes the cake, hard to argue against that, but hearing is a very close second. Well, come to think of it, smell’s a strong contender too, especially in this environment. But touch and taste are definitely vying for 4th and 5th, I think. Ok, so they are all very important.
But I digress, let’s get back to the topic at hand and focus on hearing.
The Evolution of the Ear
The actual ability to sense sound began circa 350 million years ago, likely the last of the five ways in which we perceive the world around us to develop. This was an evolutionary advancement on the simplest inner “ear” found in jawless fish, which consisted of a small sac filled with sensory cells that could detect movement and changes in water pressure. An organ that was more related to the sense of touch than to sound as it was used to sense changes in water pressure, allowing the animals to detect predators and prey around them. A spotty fossil record makes it difficult to gauge the dates precisely, but this organ was in play around 500 million years ago.
A fish’s ear consists of only the most basic part of our much more complex mammalian ear. Neurons sense pressure changes in a simple fluid-filled sac and send impulses to the brain.
Over the next 150 million years, the middle ear developed in early amphibians, whereby a small bone called the stapes evolved to connect the inner ear to the jawbone. This allowed for better sound transmission and detection of airborne sound waves.
Another 150 million years passed, during which time there was the development of the outer ear. Early reptiles emerged, and with them came the development of a tympanic membrane, or eardrum, which allowed for better sound detection.
And finally, the pinna, or auricle, which is the visible portion of the ear, evolved later in mammals and provided greater sensitivity to sounds in the environment.
So, who has the Ultimate Ears?
Could it be the Kudu?
Their massive satellite dish-like ears protrude from these beautiful animals’ craniums and can be angled any which way.
The Rhino?
A rhino’s hearing far outstrips its sense of sight (although their visual deficiencies are often exaggerated), and one can see those same swivelling satellites mounted atop their huge skulls.
A rhino’s hearing far outstrips its sense of sight (although their visual deficiencies are often exaggerated) and one can see those same swivelling satellites mounted atop their huge skulls.
What about Lions?
One of the two Ntsevu Lionesses currently raising the last litter of cubs sired by the Birmingham Coalition on Londolozi.
Able to hear their compatriots’ or enemies’ calls from up to 8km (5 miles) away, but is that not rather due to the spectacularly loud roar of the other?
Wild dogs?
Wild dogs are all ears, an adaptation mainly suited to hearing each other’s contact calls after being separated, often over massive distances, during the hunt.
Or is it the Aardvark?
Their huge ears are able to detect the rustling of termites under the ground!
Owls?
Not only are owls ears extremely sensitive, but they are also positioned at different heights on either side of the head, allowing for even greater accuracy in their detection of a scurrying bushveld gerbil or unwary lizard. Bear in mind that those “ear tufts” on the side of their heads are more for nonverbal communication of mood between owls and are used in camouflage. Their ears are actually just small holes on either side of their head roughly in line with their eyes.
But surely it must be Bats?
Bats, I have decided, are disqualified from this competition for doping; their sonic capabilities are beyond compare and used in a way completely alien to the rest of the contenders!
And the winner is…
Now, all the above are extremely strong challengers, but the award for the most able auditor must go to the Elephant. These behemoths have refined their sense of hearing to be able to detect infrasonic wavelengths of sound, sounds that are way below the human hearing threshold. A point to note here is that the longer the wavelength, the lower or deeper the sound. Wavelengths accessible to elephants can be extremely long, around 65m (215ft), as opposed to the paltry 17m (55ft) accessible to us humans.
The winner, and not just due to having the most prominent ears!
Now, at this point, one may try to note that elephants actually hear these infrasonic frequencies through their feet and not their ears. Now, I’m tempted to call this cheating as they “feel” the rumbles rather than hear them. But in the end, what is hearing anyway other than feeling vibrations in the air and translating that into information. So I’ll give it to them, they do “hear” these long-distance vocalisations through their feet.
These massive feet can detect not only the stamping of a nearby individual but also feel the vocalisations of other elephant many kilometres away!
And so, the elephant appears to be the true winner, but perhaps there are some strong contenders that I have missed? Let us know your thoughts below; the elephant may be stripped of this prodigious honour and the prize handed over to one very specialised listener!
Reference: https://www.offthescaleangling.ie/the-science-bit/fish-hearing/
All Londolozi’s blogs are so interesting and one can learn so much. Thanks for this “hearing” blog, Kyle!
Unfair to bats!
Just kidding. Really great article. Such variety! Of course, it reminds me of when my wife was sure I had a hearing problem and demanded that I be tested by an audiologist, specifically a female one. I complied, and after the testing, the audiologist told my wife, “Your husband does not have a hearing problem. He has a listening problem. He does not need a hearing aid. He needs a shock collar!”
I miss Othawa male lion a lot. He was a beautiful lion.
Kyle you have given us a food for thought about the different sound waves. Very interesting thanks for this interesting blog. Hope your ear drum is all well now. Very painful I’m sure.
Thanks Kyle, I did not guess elephants. Very interesting.
But, Wait!!! You asked “Who has the ultimate ears?” If elephants are hearing through their feet, that’s cheating! 😉😉😉
I’m sorry to learn of your temporary hearing loss, but out of that experience came this interesting article. I probably would have selected the elephant as well, even though technically their ears are not truly their main source of hearing. Actually I would have thought a few birds would have made the list besides owls, but that’s the difference between professionals who deal with sounds everyday and the novices that assign outstanding hearing to animals that really don’t qualify as reigning supreme.
Terrific post Kyle, but now you’ve got me thinking about bats!!