Welcome to the Bedtime Scientist.
Tonight we're going to spend some time with sharks.
And maybe just hearing that word did something inside you.
Maybe your stomach tightened a little, maybe your chest did,
maybe your mind filled in the rest.
A lot of people feel that way about sharks.
Most of the stories we hear about them are built to make us
afraid. But tonight, we're going to do
something different. We're going to get closer.
Because something remarkable happens when you truly learn
about an animal. The fear starts changing shape.
Not disappearing completely, maybe, but turning into
something quieter, something steadier.
Wonder. So before we begin, take a deep
breath in, let it out, close your eyes and imagine the ocean
at night. Far from shore.
No boats, no city lights. Just dark water stretching in
every direction beneath the sky full of stars, And somewhere
below the surface, a shark is swimming.
Sharks have been alive on Earth for more than 400 million years.
That number is so huge that it's hard to even imagine.
So let's think about it another way.
Sharks have been around long before humans, before birds
filled the sky, before forests spread across the land, before
the very first dinosaur ever hatched from its egg.
Old oceans moving against old shores and through those oceans
were sharks. The world changed around them
again and again. Mountains rose, continents
drifted apart, Entire species appeared and vanished.
But still sharks remained. And over all that time, the
ocean came to depend on them. When sharks disappear from a
part of the ocean, everything else shifts.
The animals they once haunted grow too many.
They eat through things other creatures depend on.
Whole populations move on or vanish.
Sharks don't just live in the ocean, they help hold it
together. And yes, they do have teeth.
Rows and rows of them. A shark doesn't keep the same
teeth forever. When one falls out, another
moves forward to take its place. Behind the visible row are more
rows, waiting patiently. Over a lifetime, a shark may
grow 10s of thousands of teeth. Not because something went
wrong, but because the ocean wears things down and the shark
keeps renewing what it needs. A body designed not for
perfection, but four continuing. Most sharks aren't especially
interested in humans at all. The vast majority eat fish,
squid, crustaceans, or plankton. Tiny creatures, some too small
to see, others no bigger than your thumbnail, drifting through
the ocean in great clouds. In fact, the largest fish on
Earth is a shark, the whale shark.
It can grow longer than a school bus.
And what does it eat? Mostly plankton.
Imagine that enormous body moving calmly through dark blue
water, its mouth open, gathering tiny creatures no bigger than
your thumbnail. A giant living quietly on the
smallest things. In the ocean, there are more
than 500 kinds of sharks. Some are smaller than your arm,
some glow faintly in deep water where no light ever reaches, and
some lie on the floor of the ocean, beneath coral ledges,
frozen in place. Nurse sharks do this.
They'll lie together in groups, one beside another, resting in
the dim blue dark of the reef, completely frozen in place, just
resting together. Beneath the water, along the
length of their bodies, runs a thin canal of tiny cells.
It's called the lateral line. These cells don't see movement
in the water, they feel it. A fish turning nearby, a current
moving around a rock, the small ripple another living thing
makes by just being there. The shark feels the shape of the
ocean changing around it, even in total darkness, even when the
water is nearly black. On the shark's broad, flat nose
are tiny pores filled with soft Jelly sensors that are so
precise they can detect the electrical pulse of a heartbeat
through dark water. The shark can feel those pulses
not with its eyes but with its whole body, a living creature
guided through darkness by the faint heartbeat of another
living thing far away. Now one of my favorite sharks.
It's called the Greenland shark, and it lives in the cold water
near the Arctic, where the ocean moves beneath floating ice.
Greenland sharks grow calmly, drift calmly, live calmly.
Some Greenland sharks, alive right now have been swimming for
400 years. One animal, 4 centuries.
Cold water, unhurried movement, a heartbeat in the dark.
Sharks are not monsters waiting below the surface.
They're living creatures that have been formed by the ocean
over an almost unimaginable length of time.
Creatures that move through darkness, that feel what they
can't see. Creatures that have continued
not through anger, but through adaptation, through patience, by
continuing. And maybe that matters for us
too, because we move through darkness as well.
Not ocean darkness, but uncertainty, new things, big
feelings, the parts of life we can't fully make out yet.
And your body already knows something important.
You don't have to see everything clearly to keep moving forward.
The shark doesn't panic in the dark ocean.
It knows how to feel its way through one movement at a time.
Let's picture the shark again, far beneath the surface, the
water cool and deep around it, it's tail moving calmly from one
side to the other, it's gills opening and closing the ocean
above, fading darker and darker into night.
And ahead of it, invisible currents, tiny electrical
pulses, the living map of the ocean unfolding in every
direction, not lost, still moving.
The dark is never truly empty. It's full of life, full of
creatures that have learned over millions and millions of years
how to move through it beautifully.
And now you know that, too. If that word ever makes
something tighten inside of you again, you can think back to
this moment and remember the real animal beneath the story.
Patient and extraordinary. And just before you drift off to
dream of moonlit water, the slow rise and fall of gentle waves
and a sky full of stars, I want you to know something about you.
Your mind is a wonderful thing, so full of curiosity, and I like
your mind just the way it wonders.
I'll be back again soon to wonder more with you.