(sonic whale song)
- The sound you're hearing is a whale song,
but it's got notes outside the frequency
of other similar songs, which could mean
that this whale has been calling out for years,
and no other whale can understand it.
This mysterious whale has never been seen,
and only heard, which has led to people calling it
the loneliest whale.
(soft pensive music)
So, why have we never seen this lonely whale?
And is it really calling out with no one listening?
(soft pensive music)
In the 1950s, the United States was just beginning
its decades-long Cold War against the Soviet Union.
And to keep track of Soviet submarines,
the Navy installed a number of underwater microphones,
called hydrophones, all over the world.
This system was called
the Sound Surveillance System, or SOSUS.
Now, these hydrophones could detect a submarine
hundreds of miles away, and if that sound
was picked up on multiple hydrophones,
it could be used to triangulate
the submarine's position in the ocean.
In 1989, SOSUS picked up a series of whale songs.
Whale calls or vocalizations are sounds
that whales use to find food, navigate,
and communicate with one another.
But these songs were a little different.
They sounded a bit like a blue whale,
but blue whale songs in that region
typically had key notes between 10 to 40 hertz.
This whale, however, was communicating
with much higher notes, at 52 hertz.
Now, different species have the ability
to hear different sound frequencies.
These frequencies are measured in hertz.
You and I can hear a range of about 20 to 20,000 hertz,
which sounds like this.
(low bass pulsing to shrill tone)
And for us humans, our hearing range
changes as we get older.
Pop your headphones on.
I'll give you a second.
(mellow techno music)
Did you hear anything?
Well, if you did, congratulations,
you're probably under the age of 25.
That sound is called the mosquito tone,
which is an ear-splitting 17.4 thousand hertz.
And the older you get, the less likely you are
to be able to hear higher tones like this one.
This all has to do with how your hearing works.
When something produces a sound,
it creates a wave that travels through the air.
That wave hits your eardrum,
sending vibrations farther into your ear
where specialized cells turn them into electrical signals,
which your brain processes as sound.
But as you get older, those cells can become damaged
and less sensitive to some frequencies of sound.
Baleen whales can hear between about 10 hertz
and 15,000 hertz, with different species
having sweet spots of hearing somewhere in that range.
Oh, and I should probably mention that the blue whale
is the biggest animal on the planet.
In fact, it's the largest animal
scientists believe has ever lived, like much bigger
than the largest dinosaur that existed, kind of big.
A blue whale call can reach up to 188 decibels underwater,
which is around 125 decibels in the air,
and that's really loud, like standing next
to an exploding firework loud,
loud enough to cause ear injury.
But they're not the loudest animals on Earth.
That honor goes to the sperm whale,
whose clicks can reach over 200 decibels.
The loudest sound NASA has ever recorded was 204 decibels
during a Saturn-V rocket launch.
(whirring sonic boom)
Though the measurements aren't perfect comparisons,
because sound moves differently through water and air,
the sperm whale clicks would be
over 140 decibel sounds above water.
That's still really gonna hurt.
All right, so how do whales sing?
Well, just like humans, filter-feeding baleen whales
use their larynx to make vocalizations.
To create their distinctive calls,
air passes from their lungs through their larynx,
causing vocal folds to vibrate.
Those vibrations travel out into the water as sound waves.
This is similar to how human vocal cords work.
Both use air from the lungs to move a larynx
to create sound.
For the whales, air from the larynx
can pass into a laryngeal sac,
which is like a big balloon in their throat.
A whale vocalizing in deep water
can then transfer the air back to the lungs
and call again without having to breathe.
But whale calls are much deeper than typical human speech.
And, we're born with the ability to talk,
or should I say, scream, much higher.
(baby crying)
Babies' cries can reach even higher frequencies
than adult speech.
This comes from the length of folds inside our larynx.
Smaller folds vibrate faster as air rushes past them,
yielding higher notes, so babies can reach
those super high tones.
But our voices get deeper as we grow older
and these folds grow larger,
and whales' voices might get deeper as they age, too.
More recent recordings of the 52-hertz whale
suggested its highest notes
have actually dropped down to about 46 hertz.
And this might not be restricted
to just whale aging either.
Blue whales elsewhere in the world
have been getting lower in pitch, too.
No one quite knows why this is happening,
though one hypothesis is that it's related
to the end of large-scale whaling 60 years ago.
Now, each species of whale creates
its own type of call or song.
And scientists have found
that just like we each have different voices,
dialects, and accents, so, too, the whales.
Some sperm whales may even be able tell each other apart,
even when they're all making the same set of clicks,
based on their sound qualities,
just like you can tell my voice from your friend's.
Each call is made up of many different notes,
just like a song you or I might sing.
And each note creates a slightly different sound wave.
You've probably seen sound waves drawn like this,
like transverse or side waves.
Now, transverse waves are just like the waves created
when you drop a rock in a lake.
They create ripples that go up and down in every direction.
Showing sound as a transverse wave
is a way of visualizing it in a really simple form,
but it's not really showing you what's actually happening.
Now, this is much better.
This is called a longitudinal wave,
which is actually showing how air molecules vibrate
when a sound is created.
Each pulse of the wave has areas of compression,
where the particles are close together,
and rarefaction, where the particles are farther apart.
The amplitude, or how loud the sound is,
is a measure by how far each individual particle of air
is displaced from its starting position,
or the equilibrium, as it swings back and forth.
The bigger the displacement of each air particle,
the higher the amplitude and the louder the sound.
The other important measurement of a sound wave
is its wavelength.
This is the distance it takes for a full cycle
of rarefaction and compression to occur.
The shorter the wavelength, the higher the frequency.
Frequency is how many waves pass through a given point
in a period of time.
For sound, this is often measured in hertz,
or how many waves pass through a point in one second.
Right now, five crests are passing through
the center of the screen each second,
because it's slowed down to a frequency of just five hertz.
If we speed it back up to 350 hertz,
which is a frequency of 350 waves per second,
now you can hear a higher tone.
And sound works a little different underwater,
which you've probably noticed
if you've ever dunked your head in a swimming pool
and tried to hear what your friends were saying above.
Sound waves travel at different speeds
through different materials,
moving about four times faster through freshwater than air
at a speed of around 1500 meters per second.
And it moves even a bit faster than that through saltwater.
This is because the molecules in water
are much closer together than the molecules in air.
As the wave reaches the water molecules,
they bump into the next closest molecule
and transmits the wave faster than air.
And we're not done.
The ocean has certain properties
that help the sound travel even longer distances.
So, the deeper you get into the ocean,
the colder it gets, right?
(mellow techno music)
As you move through the ocean, you also move
through different zones of pressure and salinity.
These can all affect how sound travels.
As a whale's call moves through the ocean,
it interacts with these different properties of water.
Something really cool happens
when you reach about 600 to 1200 meters down.
At that point, you're in the SOFAR channel,
which stands for the Sound Fixing And Ranging channel.
At that depth, the properties of the water
inhibit the movement of sound waves,
causing it to travel at slow speeds.
When sound travels up in this region,
it increases in speed as the water temperature rises.
This creates a difference in sound speed,
which causes the sound to refract back down.
As it travels down in this region,
it hits areas of increasing pressure,
again changing the sound speed
and causing it to refract back up.
In this way, the water properties
refract the sound waves of the whale's song
up and down, over and over again.
This refraction helps a whale's song travel
hundreds to thousands of kilometers away.
(mellow techno music)
And this is why scientists have been able
to record sound from the 52-hertz whale
over the course of many years,
but have never actually seen it.
They've always been really far away.
And they've recorded its call all over the Pacific Ocean,
spanning from the California Coast all the way up to Alaska.
While marine biologists believe based on its movements
that it may have been a blue or even possibly a fin whale,
no one's ever seen it, so they can't confirm
what kind of whale it is.
And some scientists think he or she
may not actually be alone, but just a bit odd.
Researchers have suggested that other whales
can likely still understand it
despite its potentially tone-deaf calls,
and that it might even be vocalizing
in a specific whale dialect.
And yes, you heard me right,
whales have regional dialects just like us.
How cool is that?
Blue whales in the North Pacific
sound different from ones in the Atlantic,
and both of those sound different from Antarctic ones.
It's hard to know if the 52-hertz whale is really lonely,
but it's certainly not the first time that whales
have been swimming alone out in the ocean.
Throughout the 18th and early 19th centuries,
the whaling industry left many species decimated.
This was mainly in the pursuit of whale oil,
which at the time was used to power oil lamps,
make soap and even margarine,
until petroleum and vegetable oil
became mainstream in the 1900s.
Now, by the way, this oil
isn't just hanging out inside the whale.
It was typically produced by boiling down the blubber,
that warm protective fat layer
right under the whale's skin.
So, let's talk a little bit about
why whale oil was so prized.
It's because it burned cleaner and brighter
than any of the other sources of oil available at that time.
And these bright, clean properties
are due to its chemical makeup.
Whale oil contains lots of triglycerides.
These are very common kinds of fats,
the same kind you find in olive oil, butter,
or even inside your own body.
These molecules contain a glycerol molecule
and three long fatty acid chains.
The fatty acid chains are long chains of carbon atoms.
And each carbon can bind to four other atoms,
including the carbon in front of and behind it.
And maybe you've heard of things
called saturated and unsaturated fats.
If a carbon chain in one of these fats is saturated,
it means that all of the carbons are single-bonded
to four other atoms: the carbon in front of
and behind it, and two hydrogens.
There are no double bonds,
and these chains are relatively straight,
so they can stack easily together
and are most often solids at room temperature,
like butter, or lard, or whale blubber.
If the chain is unsaturated, it means
some of the carbons are connected by two bonds
rather than one, which can bend the chain.
This makes them harder to stack,
causing them to often be liquids,
like vegetable oil at room temperature.
But blubber isn't the only source of oil inside of whales.
Sperm whales actually have a prized oil called spermaceti
found in a specialized organ inside the whale's head.
While some other whales also have a spermaceti organ,
the sperm whale's is about a quarter
of the length of its body.
Spermaceti is structurally different from typical whale oil,
and is actually much closer to a wax.
It's made up of mostly wax esters,
which in turn, are made up of long fatty acid chains
that include oxygen-containing ester groups.
These wax esters have particularly long chains
in the sperm whales,
allowing them to store large amounts of energy,
and burn bright and clean with little scent.
And unlike typical whale oil,
spermaceti was less likely to spoil
and go rancid on the whalers' long journey home.
This has to do with the fact
that it contains fewer unsaturated fats.
These can go rancid when exposed to air,
because oxygen breaks down their carbon-carbon double bonds.
The valuable properties of the spermaceti meant
that commercial whaling for sperm whales
persisted long into the 1900s,
with over 29,000 sperm whales killed in 1964 alone.
And commercial whaling didn't officially stop
in most countries until 1986,
which is way later than I thought.
And even right now,
whaling is still happening in some countries,
including Norway and Japan,
along with some smaller communities around the world
who hunt whales as part of a subsistence lifestyle.
So, what do sperm whales use this giant organ
filled with oil in their heads for?
Well, for a long time, scientists have thought
that it's used by the whale to help control its buoyancy.
However, now, scientists think it's also likely
that the organ acts like an acoustic lens,
so that when the sperm whale makes a sound,
it comes out forward from the whale like a flashlight beam,
instead of spreading out in all directions
like a light bulb.
This sound beam is used to help sperm whales echo-locate
to find food, including giant squid.
And sperm whales eat lots and lots of squid.
Now, while they can digest
the more squishy parts of the squid bodies,
they have trouble breaking down
the hard squid beaks and pens.
Most of the time, the whales just vomit up these tough bits.
Gross.
But sometimes, the whale's digestive tract
will bind them together and start to coat them
in a waxy substance called ambergris.
And it doesn't stay inside the whale.
Scientists can't be totally sure
if the ambergris comes out the front
or the back of the whale.
They think, probably the back, but when it does,
it floats around in the ocean for a while
as salt, sun, and air dehydrate it
and turn the black stinky globs into gray waxy chunks.
So, why in the world am I telling you
about gross whale poop?
Well, because it's actually really, really valuable,
like, more expensive than silver valuable.
The aged ambergris smells pretty great,
like pine and tobacco, and is used
as the basis for a number of perfumes.
Seriously.
Its particular scent comes from a chemical called ambrein,
and its lipophilic, or fat-loving molecules,
also help to keep other fragrance molecules stable
and perfume longer.
Gross,
but cool.
So, somewhere out there in the ocean,
there's a whale singing a slightly odd,
maybe out-of-tune song.
But is he or she really lonely?
We can't know for sure, we can't exactly ask it.
And we haven't heard from it since 2015.
But it's a story that is certainly connected
with a number of people over the years.
Some have written songs, created paintings,
and made all kinds of art about it.
And, if nothing else, it seems to be
doing pretty well for a whale,
even if it sings to its own tune.
(mellow techno music)