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It`s Okay To Be Smart, Why Does Every Animal Look Like This? - YouTube

Why Does Every Animal Look Like This? - YouTube

- [Host] Thank you to Brilliant for supporting PBS.

A caterpillar and a kangaroo,

it's hard to imagine two animals more different

or a stingray and a seagull or a penguin

and an ancient armored dinosaur.

These animals last common ancestor lived hundreds

of millions of years ago.

But there is one thing that all

of these and many other animals share

they're darker on top and lighter on the bottom.

(upbeat music)

All over the world, we find animals with this pattern,

whether they're predators or prey, whether they live

on land or in the ocean or in the sky.

So why did this trait evolve over and over again

in species that have almost nothing to do with each other?

(upbeat music)

Hey, smart people, Joe here, back in the 1800s,

biologists were scratching their heads.

There was just no good explanation for why animals

in a coral reef and a desert

and a Savannah and nearly every other type

of habitat on our planet all shared this shading pattern.

Then around the turn of the 20th century

an answer came from an unexpected place.

An American painter named Abbott Thayer declared

that he had cracked the code.

According to him,

this nearly universal pattern is camouflage.

As a painter, Thayer saw the world a little bit differently

than most people, he knew that to paint

a three-dimensional scene

on a two-dimensional canvas, one of the keys was shadows.

To give a flat picture, the illusion of shape,

areas cast in shadow were always darker

than areas under direct light.

But Thayer realized that in the three-dimensional world

of nature, many animals coloration canceled

out the shadows that their bodies cast under the sun.

Take this wolf, the top of its coat is dark brownish

and the colored fades to tan and then white under the belly.

So when a wolf is in the sun, it's upper body is illuminated

while it's light colored belly is in shadow

making its whole coat look roughly the same shade.

Thayer called this obliterate shading, and he believed that

by obliterating shadows,

animals made themselves look flatter.

And he argued that this let them blend

into their backgrounds so seamlessly

that they essentially disappeared.

Now, the idea of animals camouflaging

their shadows wasn't entirely new.

Other biologists in the 19th century,

had noticed this pattern in individual species,

but Thayer went much further,

extended his idea to all kinds of animals.

Thayer used his art skills to actually test his idea.

He once painted wooden birds with darker tops

and lighter undersides to show how they vanished

against the colors of their natural habitats.

Supposedly, there are two ducks in this photo,

one on the left that does not have this shading pattern

and one on the right that does.

I promise there's two ducks in that picture.

Thayer eventually got a little carried away

and argued that almost all animal coloration

of any type was for camouflage

like when he insisted that flamingos were pink

so that they would blend into the sky at sunset and sunrise.

Cute idea, but that's not how flamingos work.

His artist's side got the best of them with that one

but he was onto something with obliterate shading.

I set up this demo to show you how bonkers this effect is

in real life.

So the shape on the left really easy to pick out,

it's a white cylinder.

It's casting a shadow underneath it.

The shape on the right, it's much harder to pick out.

It looks much flatter.

It's just black on a black backdrop, but in fact,

it's counter shaded.

(swoosh music)

These days this effect that they are called

obliterate shading is known as counter shading.

And the idea that it works

as camouflage has been pretty widely accepted.

In some ways,

the explanation seems too obvious not to be true,

for instance, some animals that hang out upside down

like these caterpillars have reverse counter shading

so their bellies are darker and their backs are lighter.

It's easy to spot them when they're right side up

but when they're in their usual position

the shadows disappear, which seems like pretty good evidence

that counter shading has something to do

with hiding in the shadows,

and that's not the only evidence.

In brightly lit habitats like grasslands

and deserts where shadows are especially strong,

counter shading patterns are more pronounced,

balancing out those strong shadows.

Paleontologists have even found pigments preserved

in dinosaur fossils showing

that some dinosaurs were counter shaded.

But in science, just

because an answer seems obvious doesn't mean

that it's right.

Scientists have only recently started carefully

testing Thayer's century old idea

in controlled experiments to see

if it's really as universal as he claimed.

And while some studies have shown that counter shading

does protect animals from being spotted

it's still not exactly clear how it works.

Even if real animals don't completely disappear

like Thayer's painted birds, counter shading

could still make them harder to detect because many animals

visual systems work by zeroing in on contrast,

the difference between light and dark in a scene.

So got shadows, and you might jump out to a predator

but smooth your contrast with counter shading

and you may be harder to pick out

even if you don't completely disappear.

Counter shading might also work by erasing depth perception.

So instead of looking like a round juicy snack,

a counter shaded caterpillar might just look

like some flat boring leaf.

This is another case where it's important to remember

that not all animals see the way that we do.

Counter shading might make an animal just barely disappear

to our very awesome human vision.

But to a predator that can't see the colors

and details that we can, it might be enough to not get eaten

and good enough is all that matters in evolution.

We still don't know which explanation is right

or if maybe counter shading serves a different function

for different animals and for some species,

counter shading might not have to do with shadows at all.

The thing is, if you're a land animal, it makes sense

that you'd want to hide your shadows because predators

and prey mostly see each other from the side.

But many swimming animals don't have the luxury

of just concealing themselves from one angle.

They can be spotted from above, below,

or just about anywhere.

Plus, hiding shadows underwater isn't an easy task

because underwater sunlight gets scattered

by the water and the particles floating in it.

So light comes from above, below and the sides.

So it could be that counter shading evolved

in swimming species for a completely different reason.

To help these animals blend in when they're seen

from different angles.

Say that you're a predator looking at a fish from over here

so you're seeing it against a fairly bright background,

the fish's light belly will conceal it

against that bright background, but if you glide up here

you'll see it against darker deep water.

Now the fish's darker top side is absorbing most

of the strong light shining from above

so it's concealed against this background too.

Essentially, no matter where you look at it from

the fish's body reflects

about the same amount of light as its background

making it nearly invisible, at least near the surface,

'cause once you get a few hundred meters underwater

the only light is coming from above.

And no matter how white a fish's belly is,

it will cast a shadow against the bright sky.

That's why some sea creatures have little organs

on their undersides that produce light.

This is called counter illumination

and a bunch of fish, squid, crustaceans

and even sharks have adopted this trick as a way to

hide their silhouettes when they're seen from below.

The bottom line is that we don't know exactly

how counter shading works for every animal.

In some cases, it may be even more than camouflage.

Consider the penguin, they're about as counter shaded

as animals come.

It might help them blend in with different backgrounds

but penguins also seem to use their black

and white coats to regulate their temperature.

At least one study found that penguins turn their backs

to the sun when they need to warm up since the dark part

of their coat absorbs more sunlight.

What we do know is that both predators

and prey are always crafting visual tricks to try

and gain an advantage over the other

and evolutionist fashioned all sorts

of color patterns to mess with the visual cues

that many species use to make sense of the world.

Whether counter shading helps animals blend

into the background, erase their own shadows

or make three dimensions look like two,

it's worked well enough

that nature has produced this pattern over and over again

all over earth for at least tens of millions of years.

And that is something that any artist

or scientist should be impressed by.

Stay curious and scientifically speaking

that is why corgis have such cute white bellies.

Oh, hey, I didn't see you there.

Thanks for sticking on to the end of the video.

I want to say a huge thank you

to everyone who supports the show

on Patreon for helping us make these videos.

We literally could not do it without you

and it's a great way to find out about our videos

before anybody else.

So you can get right in there as soon as we upload

and help other people find these videos

and this great algorithmic adventure that we call YouTube.

Another way to do that is to press that subscribe button.

If you're not already subscribed, maybe hit the bell.

I know everybody tells you to do that

but I'm gonna do it too.

All right, check out the LinkedIn description.

We'll see you in the next video.

And thank you to Brilliant for supporting PBS.

Brilliant is an online learning platform

for STEM with hands-on interactive lessons.

Brilliant is for curious learners

both young and old, professional and inexperienced.

Brilliant courses teach you how to think

via interactive lessons,

problem solving activities and exercises.

And they also teach you how to solve problems

with interactive lessons in STEM.

For example, brilliant.org offers a course

called computational biology.

Computational biology merges the algorithmic thinking

of the computer scientist with the problem solving approach

of the physicist to address the problems of biology.

Since 2000, an ocean of sequencing data has emerged

that allows researchers and students to ask new questions.

Here students develop an intuition

for selecting foundational problems

in computational biology, like how do I reconstruct genomes?

Sequence alignment, building phylogenetic trees to look

at evolutionary relationships.

The course also addresses some physical chemical issues

of molecular biology like RNA folding.

To learn more about brilliant, go to brilliant.org/besmart.

This pattern, whether they're predators or prey

whether they live in the land or in the land.

Earthworms in the land.

Okay

Learn languages from TV shows, movies, news, articles and more! Try LingQ for FREE

Why Does Every Animal Look Like This? - YouTube Warum sehen alle Tiere so aus? - YouTube ¿Por qué todos los animales tienen este aspecto? - YouTube Pourquoi tous les animaux ressemblent-ils à ça ? - YouTube なぜどの動物もこんな姿をしているのか?- YouTube Waarom ziet elk dier er zo uit? - YouTube Dlaczego każde zwierzę tak wygląda? - YouTube Porque é que todos os animais têm este aspeto? - YouTube Почему все животные выглядят так? - YouTube Neden Her Hayvan Böyle Görünüyor? - YouTube Чому всі тварини виглядають так? - YouTube 为什么每种动物都是这个样子? - YouTube 為什麼每種動物都是這個樣子? - Youtube

- [Host] Thank you to Brilliant for supporting PBS.

A caterpillar and a kangaroo,

it's hard to imagine two animals more different

or a stingray and a seagull or a penguin ||скат|||||| ||скат|||чайка|||

and an ancient armored dinosaur.

These animals last common ancestor lived hundreds

of millions of years ago.

But there is one thing that all

of these and many other animals share

they're darker on top and lighter on the bottom.

(upbeat music)

All over the world, we find animals with this pattern,

whether they're predators or prey, whether they live

on land or in the ocean or in the sky.

So why did this trait evolve over and over again

in species that have almost nothing to do with each other?

(upbeat music)

Hey, smart people, Joe here, back in the 1800s,

biologists were scratching their heads.

There was just no good explanation for why animals

in a coral reef and a desert

and a Savannah and nearly every other type

of habitat on our planet all shared this shading pattern. ||||||||затемнення|

Then around the turn of the 20th century

an answer came from an unexpected place.

An American painter named Abbott Thayer declared |||||Тейер| ||художник||Аббот|Тейєр|

that he had cracked the code.

According to him,

this nearly universal pattern is camouflage.

As a painter, Thayer saw the world a little bit differently

than most people, he knew that to paint

a three-dimensional scene

on a two-dimensional canvas, one of the keys was shadows.

To give a flat picture, the illusion of shape,

areas cast in shadow were always darker

than areas under direct light.

But Thayer realized that in the three-dimensional world

of nature, many animals coloration canceled ||||забарвлення т|зникла

out the shadows that their bodies cast under the sun.

Take this wolf, the top of its coat is dark brownish |||||||шерсть|||коричнюватий

and the colored fades to tan and then white under the belly. |||||пісочний||||||

So when a wolf is in the sun, it's upper body is illuminated

while it's light colored belly is in shadow

making its whole coat look roughly the same shade.

Thayer called this obliterate shading, and he believed that |||знищити|||||

by obliterating shadows, |обезображивая| |знищуючи|

animals made themselves look flatter. ||||плоскішими

And he argued that this let them blend

into their backgrounds so seamlessly ||життєв||

that they essentially disappeared.

Now, the idea of animals camouflaging |||||маскування твар

their shadows wasn't entirely new.

Other biologists in the 19th century,

had noticed this pattern in individual species,

but Thayer went much further,

extended his idea to all kinds of animals.

Thayer used his art skills to actually test his idea.

He once painted wooden birds with darker tops |||дерев'яні||||

and lighter undersides to show how they vanished ||днища|||||

against the colors of their natural habitats.

Supposedly, there are two ducks in this photo,

one on the left that does not have this shading pattern

and one on the right that does.

I promise there's two ducks in that picture.

Thayer eventually got a little carried away

and argued that almost all animal coloration

of any type was for camouflage

like when he insisted that flamingos were pink |||наполягав||фламінго||

so that they would blend into the sky at sunset and sunrise.

Cute idea, but that's not how flamingos work.

His artist's side got the best of them with that one |художника|||||||||

but he was onto something with obliterate shading.

I set up this demo to show you how bonkers this effect is |||||||||безумный|||

in real life.

So the shape on the left really easy to pick out,

it's a white cylinder.

It's casting a shadow underneath it.

The shape on the right, it's much harder to pick out.

It looks much flatter.

It's just black on a black backdrop, but in fact,

it's counter shaded. ||затемнений

(swoosh music) свист| свист|

These days this effect that they are called

obliterate shading is known as counter shading. обезобразить||||||

And the idea that it works

as camouflage has been pretty widely accepted.

In some ways,

the explanation seems too obvious not to be true,

for instance, some animals that hang out upside down

like these caterpillars have reverse counter shading

so their bellies are darker and their backs are lighter. ||животи|||||||

It's easy to spot them when they're right side up

but when they're in their usual position

the shadows disappear, which seems like pretty good evidence

that counter shading has something to do

with hiding in the shadows,

and that's not the only evidence.

In brightly lit habitats like grasslands |яскраво осв||||степи

and deserts where shadows are especially strong,

counter shading patterns are more pronounced, |||||виражені

balancing out those strong shadows.

Paleontologists have even found pigments preserved

in dinosaur fossils showing

that some dinosaurs were counter shaded.

But in science, just

because an answer seems obvious doesn't mean

that it's right.

Scientists have only recently started carefully

testing Thayer's century old idea |Тейера||| |Тейлора|||

in controlled experiments to see

if it's really as universal as he claimed.

And while some studies have shown that counter shading

does protect animals from being spotted

it's still not exactly clear how it works.

Even if real animals don't completely disappear

like Thayer's painted birds, counter shading

could still make them harder to detect because many animals

visual systems work by zeroing in on contrast, ||||наведение на ноль||| ||||зосереджую|||

the difference between light and dark in a scene.

So got shadows, and you might jump out to a predator

but smooth your contrast with counter shading

and you may be harder to pick out

even if you don't completely disappear.

Counter shading might also work by erasing depth perception.

So instead of looking like a round juicy snack,

a counter shaded caterpillar might just look

like some flat boring leaf.

This is another case where it's important to remember

that not all animals see the way that we do.

Counter shading might make an animal just barely disappear

to our very awesome human vision.

But to a predator that can't see the colors

and details that we can, it might be enough to not get eaten

and good enough is all that matters in evolution.

We still don't know which explanation is right

or if maybe counter shading serves a different function

for different animals and for some species,

counter shading might not have to do with shadows at all.

The thing is, if you're a land animal, it makes sense

that you'd want to hide your shadows because predators

and prey mostly see each other from the side.

But many swimming animals don't have the luxury

of just concealing themselves from one angle. ||приховуючи||||

They can be spotted from above, below,

or just about anywhere.

Plus, hiding shadows underwater isn't an easy task

because underwater sunlight gets scattered

by the water and the particles floating in it.

So light comes from above, below and the sides.

So it could be that counter shading evolved

in swimming species for a completely different reason.

To help these animals blend in when they're seen

from different angles.

Say that you're a predator looking at a fish from over here

so you're seeing it against a fairly bright background, ||||||досить||

the fish's light belly will conceal it |риби||||сховає його|

against that bright background, but if you glide up here

you'll see it against darker deep water.

Now the fish's darker top side is absorbing most

of the strong light shining from above

so it's concealed against this background too.

Essentially, no matter where you look at it from

the fish's body reflects

about the same amount of light as its background

making it nearly invisible, at least near the surface,

'cause once you get a few hundred meters underwater

the only light is coming from above.

And no matter how white a fish's belly is,

it will cast a shadow against the bright sky.

That's why some sea creatures have little organs

on their undersides that produce light.

This is called counter illumination

and a bunch of fish, squid, crustaceans

and even sharks have adopted this trick as a way to

hide their silhouettes when they're seen from below.

The bottom line is that we don't know exactly

how counter shading works for every animal.

In some cases, it may be even more than camouflage.

Consider the penguin, they're about as counter shaded

as animals come.

It might help them blend in with different backgrounds

but penguins also seem to use their black |пінгвіни||||||

and white coats to regulate their temperature.

At least one study found that penguins turn their backs

to the sun when they need to warm up since the dark part

of their coat absorbs more sunlight.

What we do know is that both predators

and prey are always crafting visual tricks to try

and gain an advantage over the other

and evolutionist fashioned all sorts |еволюціоніст|||

of color patterns to mess with the visual cues

that many species use to make sense of the world.

Whether counter shading helps animals blend

into the background, erase their own shadows

or make three dimensions look like two,

it's worked well enough

that nature has produced this pattern over and over again

all over earth for at least tens of millions of years.

And that is something that any artist

or scientist should be impressed by. ||||вражений|

Stay curious and scientifically speaking |||науково|

that is why corgis have such cute white bellies. |||коргі|||||

Oh, hey, I didn't see you there.

Thanks for sticking on to the end of the video.

I want to say a huge thank you

to everyone who supports the show

on Patreon for helping us make these videos.

We literally could not do it without you

and it's a great way to find out about our videos

before anybody else.

So you can get right in there as soon as we upload

and help other people find these videos

and this great algorithmic adventure that we call YouTube.

Another way to do that is to press that subscribe button.

If you're not already subscribed, maybe hit the bell.

I know everybody tells you to do that

but I'm gonna do it too.

All right, check out the LinkedIn description.

We'll see you in the next video.

And thank you to Brilliant for supporting PBS.

Brilliant is an online learning platform

for STEM with hands-on interactive lessons.

Brilliant is for curious learners

both young and old, professional and inexperienced.

Brilliant courses teach you how to think

via interactive lessons,

problem solving activities and exercises.

And they also teach you how to solve problems

with interactive lessons in STEM.

For example, brilliant.org offers a course

called computational biology. |обчислювальна|

Computational biology merges the algorithmic thinking обчислювальна|||||

of the computer scientist with the problem solving approach

of the physicist to address the problems of biology.

Since 2000, an ocean of sequencing data has emerged

that allows researchers and students to ask new questions.

Here students develop an intuition

for selecting foundational problems

in computational biology, like how do I reconstruct genomes?

Sequence alignment, building phylogenetic trees to look |||филогенетический|||

at evolutionary relationships.

The course also addresses some physical chemical issues

of molecular biology like RNA folding. |||||складання

To learn more about brilliant, go to brilliant.org/besmart.

This pattern, whether they're predators or prey

whether they live in the land or in the land.

Earthworms in the land. дощові черв|||

Okay