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Welcome to the Bedtime 
Scientist. 

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Tonight we're going to spend 
some time with sharks. 

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And maybe just hearing that word
did something inside you. 

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Maybe your stomach tightened a 
little, maybe your chest did, 

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maybe your mind filled in the 
rest. 

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A lot of people feel that way 
about sharks. 

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Most of the stories we hear 
about them are built to make us 

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afraid. 
But tonight, we're going to do 

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something different. 
We're going to get closer. 

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Because something remarkable 
happens when you truly learn 

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about an animal. 
The fear starts changing shape. 

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Not disappearing completely, 
maybe, but turning into 

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something quieter, something 
steadier. 

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Wonder. 
So before we begin, take a deep 

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breath in, let it out, close 
your eyes and imagine the ocean 

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at night. 
Far from shore. 

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No boats, no city lights. 
Just dark water stretching in 

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every direction beneath the sky 
full of stars, And somewhere 

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below the surface, a shark is 
swimming. 

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Sharks have been alive on Earth 
for more than 400 million years.

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That number is so huge that it's
hard to even imagine. 

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So let's think about it another 
way. 

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Sharks have been around long 
before humans, before birds 

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filled the sky, before forests 
spread across the land, before 

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the very first dinosaur ever 
hatched from its egg. 

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Old oceans moving against old 
shores and through those oceans 

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were sharks. 
The world changed around them 

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again and again. 
Mountains rose, continents 

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drifted apart, Entire species 
appeared and vanished. 

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But still sharks remained. 
And over all that time, the 

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ocean came to depend on them. 
When sharks disappear from a 

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part of the ocean, everything 
else shifts. 

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The animals they once haunted 
grow too many. 

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They eat through things other 
creatures depend on. 

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Whole populations move on or 
vanish. 

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Sharks don't just live in the 
ocean, they help hold it 

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together. 
And yes, they do have teeth. 

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Rows and rows of them. 
A shark doesn't keep the same 

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teeth forever. 
When one falls out, another 

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moves forward to take its place.
Behind the visible row are more 

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rows, waiting patiently. 
Over a lifetime, a shark may 

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grow 10s of thousands of teeth. 
Not because something went 

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wrong, but because the ocean 
wears things down and the shark 

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keeps renewing what it needs. 
A body designed not for 

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perfection, but four continuing.
Most sharks aren't especially 

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interested in humans at all. 
The vast majority eat fish, 

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squid, crustaceans, or plankton.
Tiny creatures, some too small 

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to see, others no bigger than 
your thumbnail, drifting through

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the ocean in great clouds. 
In fact, the largest fish on 

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Earth is a shark, the whale 
shark. 

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It can grow longer than a school
bus. 

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And what does it eat? 
Mostly plankton. 

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Imagine that enormous body 
moving calmly through dark blue 

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water, its mouth open, gathering
tiny creatures no bigger than 

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your thumbnail. 
A giant living quietly on the 

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smallest things. 
In the ocean, there are more 

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than 500 kinds of sharks. 
Some are smaller than your arm, 

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some glow faintly in deep water 
where no light ever reaches, and

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some lie on the floor of the 
ocean, beneath coral ledges, 

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frozen in place. 
Nurse sharks do this. 

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They'll lie together in groups, 
one beside another, resting in 

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the dim blue dark of the reef, 
completely frozen in place, just

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resting together. 
Beneath the water, along the 

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length of their bodies, runs a 
thin canal of tiny cells. 

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It's called the lateral line. 
These cells don't see movement 

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in the water, they feel it. 
A fish turning nearby, a current

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moving around a rock, the small 
ripple another living thing 

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makes by just being there. 
The shark feels the shape of the

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ocean changing around it, even 
in total darkness, even when the

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water is nearly black. 
On the shark's broad, flat nose 

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are tiny pores filled with soft 
Jelly sensors that are so 

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precise they can detect the 
electrical pulse of a heartbeat 

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through dark water. 
The shark can feel those pulses 

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not with its eyes but with its 
whole body, a living creature 

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guided through darkness by the 
faint heartbeat of another 

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living thing far away. 
Now one of my favorite sharks. 

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It's called the Greenland shark,
and it lives in the cold water 

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near the Arctic, where the ocean
moves beneath floating ice. 

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Greenland sharks grow calmly, 
drift calmly, live calmly. 

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Some Greenland sharks, alive 
right now have been swimming for

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400 years. 
One animal, 4 centuries. 

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Cold water, unhurried movement, 
a heartbeat in the dark. 

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Sharks are not monsters waiting 
below the surface. 

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They're living creatures that 
have been formed by the ocean 

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over an almost unimaginable 
length of time. 

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Creatures that move through 
darkness, that feel what they 

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can't see. 
Creatures that have continued 

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not through anger, but through 
adaptation, through patience, by

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continuing. 
And maybe that matters for us 

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too, because we move through 
darkness as well. 

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Not ocean darkness, but 
uncertainty, new things, big 

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feelings, the parts of life we 
can't fully make out yet. 

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And your body already knows 
something important. 

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You don't have to see everything
clearly to keep moving forward. 

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The shark doesn't panic in the 
dark ocean. 

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It knows how to feel its way 
through one movement at a time. 

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Let's picture the shark again, 
far beneath the surface, the 

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water cool and deep around it, 
it's tail moving calmly from one

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side to the other, it's gills 
opening and closing the ocean 

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above, fading darker and darker 
into night. 

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And ahead of it, invisible 
currents, tiny electrical 

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pulses, the living map of the 
ocean unfolding in every 

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direction, not lost, still 
moving. 

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The dark is never truly empty. 
It's full of life, full of 

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creatures that have learned over
millions and millions of years 

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how to move through it 
beautifully. 

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And now you know that, too. 
If that word ever makes 

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something tighten inside of you 
again, you can think back to 

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this moment and remember the 
real animal beneath the story. 

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Patient and extraordinary. 
And just before you drift off to

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dream of moonlit water, the slow
rise and fall of gentle waves 

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and a sky full of stars, I want 
you to know something about you.

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Your mind is a wonderful thing, 
so full of curiosity, and I like

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your mind just the way it 
wonders. 

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I'll be back again soon to 
wonder more with you.