It's late o clock on Monday again, and you know what that means: Whale time.

Join me as I recount the tales of adaptation and heartbreak that lay behind every whales' song.

1/n

Imagine you're this dumb water dog, and you want to evolve into a whale in the next 20 million years. Theres just one issue: It's hard to see underwater, and your eyes are small. Clearly, you need to learn echolocation. But, that presents its own problems...

2/n

Underwater, sound attenuates quickly (high frequencies especially). To produce the needed low, powerful tones, theres one thing for a dumb water dog like you to do. You need to get big.*

*evolutionary accuracy sacrificed for the sake of narrative

3/n

So, you grow yourself a sounding board. Atop your head sits a cavity filled with lipids of lower density than the surrounding water, which focuses your voice into a concentrated beam. Irreverent sailors call this your "melon", which is really quite rude.

4/n

In a brazen display of misogyny, Belugas are sometimes called "melonheads", cause they have giant melons.

Although, this doesn't really compare to the etymology of sperm whales...

5/n

Sperm whales are named for their spermacti organ, another lipid compartment situated above the melon which serves a similar purpose.

When people first cut into the 500 gallon cavity filled with a thick milky white substance, well, you can guess what they thought.

6/n

They make sound with their "phonic lips" (or monkey lips), a voice-box like structure that evolved from the nasal cavity. Whales have to vocalize without exhaling, something generally hard for humans. So, they store air in an inflatable sac past their lips.

7/n

Here's a finite element simulation of the acoustics of a dolphin, showing the sound propagating from the phonic lips thru the melon (Cranford 2008).

I can't resist mentioning, whales don't have external ears, instead hearing thru a vibrating skull! https://www.youtube.com/watch?time_continue=5&v=j-EOSAJh10A&feature=emb_title

8/n

These clicks are real loud: Sperm whales clock in at 230 dB! For reference, jet engines are ~140 dB. You need to be this loud to communicate over 60 km like whales.

There are (rather unsubstantiated) theories that whales use this to stun prey. I can imagine it though...

9/n

Divers need to infiltrate a pod to record whale noises. Encircled by inquisitive Odontoceti, their echolocating rays noticeably heat the diver's body.

One diver put out their hand to avoid an oncoming whale: The whale's click paralyzed their hand for the next 4 hours.

10/n

Sidenote, whales are scared off by the noise of scuba gear. So, divers have to just hold their breath, and the whales treated them like another pod member.

like yes that's adorable, but holding your breath in the open ocean is kinda visceral unsettling in a thalassophobic way

In an amazing display of natural engineering, some whale calls ring across the entire globe. The culprit is a layer of
the ocean with minimal sound speed.

Just like a fiber optic cable, sound refracts towards the low-velocity channel center, traveling long distances.

11/n

This is called the SOFAR layer, presumably describing how far the sound travels.

With depth, ocean temperature decreases (lowering speed of sound), while pressure increases (raising speed). Together, sound speed is minimized at ~1km depth.

12/n

Vocalization isn't just for hunting, but socialization, mate finding, and identifying individuals. Some sing!

Now, what are the whales actually singing? I have my own theories (), but "mainstream consensus" says this is an "untestable hypothesis" smh

13/n

Unlike social mate-finding grunts, only a few species of baleen whales sing.They repeat short phrases with small variations for hours on end. A whale pod will all sing the same song (though not in unison!)
None is more lyrical than the mighty humpback:
14/n

The clear hierarchy makes this amazing: notes form phrases, which build themes, which repeat in songs.

No other animals do this! Moreover, this sort of structure is a necessary hallmark of grammar. It's entirely possible that whales have their own full-fledged language!

15/n

Inspiringly, you can derive this with information theory: https://asa.scitation.org/doi/pdf/10.1121/1.2161827?casa_token=HyV1EQ9RuZ8AAAAA:TUzNKopXuPT14mm-nzIXT_clMgWPmZDjBx7g35ZTX3-kkgqfwm3ETMAbwL7v3bSYetO4ZnnOE4wh

Also, whalesong has 1 bit of information per second, compared to human's 39 bits. For those keeping score, that's 1 trillionth the information density. But they're whales, no need to rush!

16/n

Now for the heartbreak :(

Equipped with the SOFAR layer, researchers have their finger on the pulse of whales around the planet. They hear 40 Hz blue whales and 20 Hz fin whales and... 52 Hz?

Roaming the pacific since 1990 is a lone, 52 Hz source.


17/n

No one knows if 52 blue is a hybrid, malformed, or deaf. All we hear is the lifetime of calls for companionship, invisible to any who could give it.

Yet they keep singing, no base to their treble, never knowing a friend.

The song of the loneliest whale in the world.

18/n

Humpback whale debut album:


It's haunting yet calming, like a pack of leviathan ocean dogs whining in your ear all at once. Good mood music for whale tweets.

Be kind to your local whales, lest they vaporize you with their echolocation rays.

19/n=19

Bonus content: another marine mammal with adorable vocalizations https://twitter.com/soundmigration/status/1284147067766611969?s=20