Humans have some impressive hardware which lets them hear sounds and interpret the world, but our skills pale into insignificance when you compare them with the champion listeners of the natural world. When you learn about the sensitivity to noise of animals like bats and cats, it really puts things into perspective about the fragility of our ears. Our own hearing abilities seem almost pitiful by comparison – so we need to keep them in good condition for as long as possible. Let’s have a look at the animal world’s most formidable auditory systems and learn more about how nature and noise fit together.
When you look at elephants, one of the first things you notice are their enormous ears (well, everything’s enormous, but their ears are particularly impressive). Predictably enough, these ears allow their owners to achieve some incredible auditory feats. Because of the architecture of their ears and ear canals, elephants are able to pick up what are called “infrasound” waves. That is, sound waves which are much longer than the frequencies humans can hear. If humans could hear them, they would sound like low rumbles, or a kind of meaningless hiss. For elephants, this ability enables them to be sensitive to the movement of clouds. They can physically hear when rain clouds are gathering, so they know when to head for water sources.
They also communicate across long distances using low frequency sounds. When they pound their feet against the ground, elephants set up a powerful but hardly audible vibration. Through nerve endings in their feet and ear bones, these sounds can be picked up miles away, like a kind of bush telephone.
When humans go blind, their hearing becomes doubly important, allowing them to get around more easily and detect obstacles. But, no matter how sensitive human hearing becomes, it never approaches the amazing abilities of bats.
Bats famously use something called “echolocation” to locate their prey and get around the nocturnal world. They do so by creating high frequency noises, which bounce off anything they hit, then return to the bat’s ears. Even though their brains are tiny, these amazing creatures use the echoes to create a map of their environment, enabling them to fly flawlessly through the dark.
Recently, scientists have found another amazing thing about bats. Their hearing systems seem to extend to the hairs on their wings. These wings are covered with what are known as “Merkel hairs”, which are ultra-sensitive to air movements. As the bat flies, they can pick up approaching objects and relay this information to the brain.
It’s not “hearing” as we would understand it, but like elephants who hear through their feet, bats hear through their ears and wings combined. Their whole body has evolved to interpret their environment, giving them remarkable skills.
You might think that the ocean would pose impossible challenges for hearing, and the mass of water certainly has forced nature to improvise. But dolphins in particular have met the challenge in style, developing a similar echolocation system which rivals bats in its complexity and sensitivity. In the case of dolphins, they create powerful sonic pulses from their foreheads. These sounds are directed at their target, whether that’s a rock, a ship, or a shoal of tasty fish. When they reflect back, they are “received” by the jaw of the dolphin, and then relayed back to the brain, via auditory nerves that are much broader than those of human beings.
Where dolphins differ most from land-based animals is their ears. While they do have openings on the side of their head that are linked to sound reception, they aren’t thought to be crucial to dolphin hearing. Again, other parts of their body are instrumental.
While bats, elephants, and dolphins are exceptional hearers, even domesticated cats and dogs have some extraordinary abilities that we humans lack. If you own a pet, you’ll probably have noticed their sensitivity to sudden noises. Just like wild animals, cats and dogs retain their sensitive hearing to tell them whether to flee danger. For cats, the priority is hearing sounds at high frequencies (like mice trying to hide in bushes). That’s why their ears are designed to funnel high frequency sounds from 40-50 meters away. And this is also why experts think that exposing them to amplified music can be damaging.
Dogs are slightly different. They have more sensitive ears than humans, but aren’t quite as sensitive to high frequencies as cats. Instead, they are brilliant at locating and focusing on sounds, due to highly developed muscles around their ears. That’s why you’ll see their ears pick up and rotate when danger is near – something us humans cannot do.
It’s easy to put human and animal hearing in perspective. To do so, we need to focus on the range of frequencies different animals can hear. By frequency, we mean the size of sound waves that ears can pick up, which is measured in Hertz (hz).
Humans generally have a hearing range of between 20 and 20,000 hz, which is actually very impressive. However, elephants can hear waves as low as 14 hz, while cats can hear up to 64,000 hz frequencies, and bats can sometimes pick up noises as high as 200,000 hz.
As you can see, there’s plenty of diversity in the way animals hear, and in terms of their hearing abilities, too. But the main difference is that humans can do something when their hearing fails. So, if you have any worries, contact hear.com today.
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