00:00Chances are you have a dog wagging its precious tail around the house or
00:04sniffing at your feet. Ever marveled at how keen your dog's hearing is? I mean it
00:10can hear you opening a bag of chips even if you're on a different floor in the
00:14house. Even with this amazing ability most household dogs don't have the best
00:19hearing in the animal kingdom. Actually they're not even in the top five. On that
00:25note let's venture into the world of animal hearing and try to imagine what
00:29life sounds like for other creatures. Look we humans are pretty great. We've
00:36got all kinds of talents but when it comes to the auditory Olympics we're not
00:40even in the running. Put us next to a cat or a bat and our ears look kind of basic.
00:45Take elephants for instance. They are big animals and so are their ears. Their
00:51auditory organs are capable of capturing infrasound waves. Now these are not your
00:57run-of-the-mill sound waves. They're low frequency rumbling whispers that we
01:01humans can't hear. This means elephants can pick up on things like rain clouds
01:06on the move. Not only that but these massive mammals have a pretty clever way
01:11of communicating too. They stomp the ground creating vibrations barely
01:16noticeable to us. But to elephants these vibrations are the equivalent of a
01:21long-distance phone call. The messages are received through their feet and
01:25ear bones even when they're miles apart. Talk about having a good reception.
01:34Moving on to bats. They are the masters of night navigation thanks to their use
01:40of echolocation. These animals emit high-frequency sounds which bounce back
01:46after hitting objects. This echo helps bats create a mental map allowing them
01:52to sway flawlessly in the dark. Just when we thought bats couldn't get any
01:56cooler scientists discovered their hearing capabilities extend to their
02:01wings. Special hairs called Merkel hairs sense air movements helping the bats
02:06detect upcoming objects. It's not the traditional hearing we're used to but
02:10it's a fantastic adaptation to their environment. Dolphins on the other hand
02:18are masters of watery acoustics. For starters you might think that being
02:23underwater would put a damper on hearing but dolphins have turned this challenge
02:27into an advantage. They've got their own version of echolocation emitting sonic
02:33pulses from their foreheads. These sounds bounce off objects and are picked up by
02:37the dolphins jaw before being sent to the brain via highly developed auditory
02:42nerves. Their ears though present don't play a central role in hearing like
02:48ours do. Instead dolphins have found innovative ways to listen proving yet
02:53again how awesome animals are. Don't let their domestic status fool you. Your pet
03:00cats and dogs are auditory champs. Cats ears are designed to catch high
03:04frequency sounds from up to 160 feet away. Handy for catching mice don't you
03:10think? Dogs on the other hand are pros at localizing sounds thanks to the muscles
03:16around their ears. Ever seen your pooch perk up their ears when they hear
03:20something suspicious? That's their sharp hearing at work.
03:27Even the tiniest critters buzzing around us like insects can actually listen to
03:33the world. In fact some insects have something akin to our human eardrums.
03:38It's a delicate little membrane given the name tympani. Our eardrums jiggle
03:44with the sound waves. That shaking is then turned into a signal our brain
03:48would understand. Now you've surely heard the nightly serenade of crickets or the
03:54rhythmic song of cicadas in the summer. These little symphony masters use exactly
03:59this kind of setup to listen to their world. That's not all though. Some bugs
04:05take a different approach to eavesdropping on their surroundings.
04:08They've got these sensory cells right in the middle of their antennae. This
04:13structure is called the Johnston's organ. Take mosquitoes for instance or bees or
04:18even fruit flies. They use their antennae not just to feel their way around but to
04:24listen in on the world too. It gets even wilder. Hawk moths, some dusky nocturnal
04:31creatures have this unique organ nestled right in their mouths. It's like a
04:35superpower that lets them hear ultrasonic sounds. With this they can
04:40dodge the dangerous dives of bats out on the hunt.
04:46When it comes to the ultimate hearing trophy, the animal kingdom has a
04:51completely unique winner. It's actually a moth. Not just any moth though. It's the
04:57greater wax moth discovered by the scientists based in Glasgow, Scotland.
05:02They've got some fascinating insights about these moths that make our ears
05:07want to stand up and listen. Just to give you some context, the greater wax moth
05:13does not stand out when it comes to its appearance. I mean it's brown. As for its
05:20daily activities, it loves nibbling on honeycomb. Despite blending in seamlessly
05:26in the animal kingdom, it's got a serious set of ears. How good is its hearing you
05:31ask? Well, it's been found that this tiny creature can pick up on sounds at
05:37frequencies up to 300 kilohertz. By comparison, our human ears can only detect
05:43sounds up to around 20 kilohertz. This already unimpressive ability drops to
05:48about 15 kilohertz as we grow older. I mean not even dolphins can compete. They
05:55can only hear sounds up to about 160 kilohertz. You're probably wondering why
06:04would a moth need such super hearing? Scientists explain that the reason
06:08behind this extraordinary hearing lies in a survival instinct. Predation to be
06:13precise. Bats use high-frequency echolocation calls to find their tasty
06:18moth meals amongst other insects. But these clever little moths have evolved
06:23to pick up frequencies even bats might not hit. Despite this reasoning, it was a
06:30bit of a mystery as to why these moths would even need to hear such high
06:34frequencies. During the research, specialists discovered that their
06:38recording at high-frequency ultrasound is tricky business. So there's a chance
06:43that bats might actually be capable of emitting calls at these super high
06:47frequencies that the moths can hear. To uncover all this, scientists used a
06:53specially designed ultrasonic device. It emitted these crazy high frequencies and
06:58they then looked at the moths reactions using electrodes to measure their neural
07:03responses. The practical implications of this research could be far-reaching.
07:11Understanding the inner workings of the greater wax moth's ear could have a big
07:15impact on the world of technology. This knowledge could help researchers build
07:20super tiny microphones, for example. We know that all sorts of critters, from the
07:27tiny creatures scuttling on the ground to the gigantic ones swimming in the
07:31ocean, can pick up on certain sound frequencies that our human ears just
07:35can't. However, scientists have made a fascinating discovery. They've shown for
07:42the first time that our ability to pick up on tiny differences in sound
07:46frequencies might just be superior to that of animals, thanks to our
07:50individual neurons. How did they prove this, you ask? Well, they took advantage
07:56of a unique technique that lets them record what single neurons are up to in
08:01the auditory cortex. That's the part of our brain that's a major player in
08:05processing sounds when we're exposed to various noises. You see, most of what we
08:12know about the auditory cortex was unearthed from past research that
08:16studied how animals' neural activity reacts to sound. Those studies were super
08:21useful in giving us a peek into how sounds are processed in our auditory
08:25system, but they didn't really let us know what sets us humans apart in the
08:30way we perceive sounds. When scientists tested how we respond to made-up sounds,
08:37they found out that our neurons in the auditory cortex responded with a
08:41surprising level of accuracy to specific frequencies. They could even pick up
08:46differences as tiny as a quarter of a tone just by looking at the reactions of
08:51individual neurons. That's a level of detail that you wouldn't typically find
08:57in the auditory cortex of other mammals. The one exception might be bats, who use
09:03their hearing in pretty unique ways. But this could explain why we humans can
09:08distinguish between frequencies better than animals. It seems like the way our
09:12brains process sound frequencies has some special features to it. When they
09:18played more natural sounds like conversations, music, and everyday noise,
09:22the neurons showed complex activity patterns. These patterns couldn't be
09:27fully explained just by the neurons' frequency selectivity. Animal studies
09:32have shown similar phenomena, but it's the first time we've seen this in humans.
09:37That's it for today! So hey, if you pacified your curiosity, then give the
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09:45on these videos and stay on the Bright Side!
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