In the animal world making sound is key to survival.
Cicadas do it, lyrebirds do it, and even fishes in the ocean do it.
Male animals are especially vocal when they're trying to attract a mate.
So let's take a closer look at the ingenious ways animals make noise including fish farts (yes, really!)
Fish farts and 'drumming' muscles
Sound is created by vibration.
When an object vibrates it causes the air molecules around it to vibrate. This in turn creates ripples that hit our eardrums causing them to vibrate and produce a signal that is detected by our brain and interpreted as sound.
Lots of animals, including human crooners, make sound by using air from their lungs to vibrate flaps called vocal folds (commonly called vocal cords).
But even fish — that have nothing remotely resembling these anatomical features — can make sound.
So, how do they do it?
Some grind their bones together (move over the night-time teeth-grinder), while the lovely herring are believed to communicate by blowing bubbles out their anus.
Australian fish have a little more decorum. They've generally been found to make sounds by using special 'sonic' or 'drumming' muscles to 'strum' their swim bladders — balloon like organs that they use to help keep them buoyant.
Turn sound on to experience a fish 'symphony':
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First you hear some fish 'soloists': a hooting batfish, a knocking catfish, a beeping terapon, and a honking mullaway.
You'll also hear a couple of fish "choruses", including the racket made by a plethora of plankton-eating fish on the Great Barrier Reef.
If we could hear better underwater, the sound would be quite deafening.
The snorts, grunts and bellows of the koala
A little closer to a human soloist, well at least a yodeller, is the koala.
The male of the species is renowned for his loud vocal displays designed to impress females and announce his territory.
First, he starts off making repeated snore-like snorts as he inhales, and then makes a grunty belch sound as he exhales. As he picks up speed the sounds turn into an incredibly loud bellowing.
Watch this male koala get ready to bellow — and then let it rip:
Loading...Amazingly, the sound a male koala makes is about 20 times lower than it should be given his size, thanks to the vibration of an extra pair of vocal folds that sit between his oral and nasal cavities.
The larger the male, the lower his sound, and the further it travels to advertise his size and prowess. And apparently, male koala sounds are highly individual and helps them be identified.
Female koalas tend to screech and cry rather than bellow, and usually only if they are distressed or being pursued by an unwanted male.
The ultrasound of hunting bats
Small hunting bats like the large-footed myotis (Myotis macropus) emit ultrasound — frequencies above 20,000 Hertz that are beyond our ability to hear.
The bats produce these waves for navigation (so-called 'echolocation'). Not that they're blind, mind you. They just need a way to sense their environment when they hunt at night.
The large-footed myotis trawls for fish and insects by flying just 15 centimetres above the surface of water in the dark. So it has to know exactly when to reach out its (relatively) large claws to its prey.
To do this, the bat produces pulses of ultrasound that bounce back off the water surface and gives it information on what's there. Once it picks up something promising it sends out more pulses to get a clearer picture.
This bat sound has been slowed down so you can hear it:
Loading...Make sure you listen to the end where you'll hear the frantic "feeding buzz" that occurs just at the time the bat tries to swipe dinner from the water surface.
The infrasound of blue whales
At the opposite end of sound frequencies that humans can't hear is 'infrasound' — below 20Hz. These are the frequencies exploited by one of the largest and loudest animals in the world: the blue whale.
Blue whales sing by vibrating a U-shaped fold of skin that sits between their lungs and a special air sac, which also helps amplify the sound through a process called resonance. By circulating the air back and forth they are able to make continuous calls.
The low-frequency soundwaves pygmy blue whales produce (up to 75-metres in wavelength) can travel far and be heard hundreds of kilometres away.
Males sing to attract females, and more so when they are moving north heading towards the breeding grounds, and less when the party's over.
The whale song in this video was recorded under water and sped up six times so humans can hear it:
Loading...A big vocal sac is a boon for frogs
You might have noticed male frogs have the ability to go all night – making calls, that is.
Frogs don't have ribs and a diaphragm like we do, so they have to go to a lot more effort to fill their lungs with air they can use to vibrate their vocal folds.
First, they take air in through their nostrils by lowering the floor of their mouth (to create a negative pressure).
Then they block their nostrils and lift the floor of their mouth to push the air into their lungs.
They repeatedly do this until their lungs are full.
And in some frogs this is aided by a vocal sac — which can balloon out below their chin, or in some cases to either side – to recycle the air so they can keep making noise without gasping for air.
The sac also acts as a resonator to help distribute the calls far and wide.
Check out the sound of this tree frog with a generous vocal sac:
Loading...The lyrical lyrebird
The superb lyrebird has to be the cleverest songbird in the pack. Apart from a range of whistles and cackling that they use for their own song, it is famous for its mimicry.
Like other birds, the secret to the songs it produces lies in an organ called the syrinx, which is located where the windpipe branches into two in the chest.
The lyrebird's super flexibility in muscles around this organ means they can rapidly and independently control airflow through the two branches of their windpipe, producing all kinds of sounds in rapid succession.
But lyrebirds don't just mimic other birds. If they are bred in captivity, they also mimic sounds from the human world – from chainsaws and construction sounds to evacuation alarms and even human voices.
This superb lyrebird at Sydney's Taronga Zoo reproduces the unsettling screams of a baby:
Crazy loud cicadas
The prize for the loudest insect in the world goes to the cicada with some large species reaching more than 100 decibels – which is somewhere between the volume of a blender and a baby crying.
And Australia is cicada capital, boasting 800 known species.
As male cicadas start up their calls to attract a mate or deter predators, others join in and together they create a deafening and pulsating chorus.
Like frogs and birds, every species of cicada has its own unique sound, which is how females manage to recognise the right males.
At the heart of their sound-generating machinery are membranes in the abdomen called timbals. Like a tin clicker, they make a repetitive clicking sound by flexing a series of convex ribs along these membranes – buckling and straightening them several hundred times a second.
The sound is then amplified in an air sac in the cicada's abdomen, before being pushed out through holes in its underside.
Listen to the sound of the gorgeous golden twanger from the Blue Mountains in NSW:
Loading...Thanks to: Dr John Debs, Australian National University; Dr Nathan Emery, Botanic Gardens of Sydney; Dr Leroy Gonsalves, NSW Department of Primary Industries; Dr Capri Jolliffe, Blue Whale Project Oz; Dr Brad Law, NSW Primary Industries; Dr Alex Maisey, La Trobe University; Dr Robert McCauley, Curtin University; Dr Miles Parsons, Australian Institute of Marine Science; Dr Jodi Rowley, Australian Museum.
Want to hear more sounds of Australia? Tune into Catalyst's Soundtrack of Australia on Tuesday, August 16 at 8.30pm on ABC TV and ABC iview.
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August 13, 2023 at 03:30AM
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How do animals make all those weird and wonderful sounds? - ABC News
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