Original subtitles

Dogs were our first ever pets.

They've now shared our homes for 30,000 years.

Not surprising, then, we call them "Man's best friend."

But despite our close relationship,

dogs have been hiding a remarkable extra super sense from us all this time.

Meet Tweed and her litter of five puppies.

They'll open their eyes after one week

and hear after three.

But one sense is perfectly formed from birth.

The ability to smell.

And they can do that 100,000 times better than we can.

Until recently, we thought it was that amazing sense of smell

that helped them find their way back to the food and warmth provided by Mom.

But now their secret has been revealed,

and it's more extraordinary than anyone ever imagined.

So what sensory superpower have dogs been hiding all this time?

It turns out little Dickens here has a thermal sensor in the tip of his nose.

He can detect warmth like a heat-seeking missile.

To see how that works, let's switch to a thermal imaging camera.

The warmest areas are red,

and the biggest source of heat, his mom's tummy.

Little Dickens straying away from his mom is no cause for alarm…

because the thermal sensor in his nose will guide him back to safety.

In every dog's brain, there's an area called "the somatosensory cortex"

that not only processes smell, but also thermal radiation.

As our pup develops into an adult,

this extra super sense will help him through his domestic life.

In the wild, a Labrador like Dickens could use his thermal nose

to spot the heat of a prey animal,

allowing him to hunt even if his other senses were impaired.

Even though their sense of smell is 100,000 times better than humans,

they're really using their ability to sense heat to find food.

It also explains that uncanny knack for stealing a warm seat.

As this spectacular extra sense has only previously been found

in snakes, black fire beetles, and vampire bats,

Dickens is a member of a pretty exclusive club.

Just when we think we know them inside out,

dogs surprise us with something new.

So what super senses have our other pets been keeping hidden from us?

Our next pet has an even more impressive superpower

that means no matter where he is, he can always find his way home.

In Utah, Zac Robinson has found a fun way to spend time with his pet

while at the same time harnessing its unique navigation abilities.

I love the desert.

It can look so boring, and desolate, and empty,

and then you just come around a corner, and there is a 200-foot cliff drop.

I could spend the rest of my life just exploring out here.

But Zac's not venturing into these arid uplands alone.

For the past eight years, he's had a rather unusual wingman.

His pet cat, Kenny.

I was going on climbing trips.

Other folks would bring their dogs for the weekend,

and I just really felt bad leaving Kenny at home.

Then I thought, "Man, this would be great if I could just bring him along

and spend that extra time with him,"

and… and we started doing some trips.

Since then, Zac and Kenny have hiked over 200 miles together,

leading to a remarkable synchronicity.

Kenny's tail is usually up.

He's walking around, he's got his tail crooked up like a question mark.

That's when I know that he has got good spirits.

We're taking our time, he'll stop and sniff a plant.

And once it gets hot out, we're seeking shade everywhere.

After their first few hikes together, something remarkable happened.

Yeah, go, go, go, go, go!

Kenny began to lead the way.

He'll get 30, 50 feet away from me.

But he'll stop and meow until I catch up.

Then he'll just check in with me, give me a quick little bump,

and then move on his way.

Go on.

There's definitely a partnership as we're walking around

and… and checking things out.

I really feel like that we're both kind of doing this together.

Thanks to Kenny, these two should never get lost.

It's believed that cats navigate using an in-built GPS system

called "magnetoreception,"

an ability to sense the planet's magnetic forces using their bodies.

And out here in the desert, it's on the return leg

that Kenny's navigation skills really kick in.

You can see those instincts kinda come into play.

He's got a really good sense of direction.

He knows which direction is home,

and he will pull straight back towards the car, back towards camp.

Go, go, go, go, go.

It seems that once a pet has locked into a location,

it can always find its way back there

simply by following the magnetic forces leading to it.

Last half mile or so, he starts moving a little faster.

And he knows that we're getting close to camp.

I can light a fire.

He'll usually crawl up into the chair, and just watch me cook dinner.

And we can sit together in the love seat and just kinda watch the stars go by

as the fire dies.

I think, with these trips, we've really gotten a lot closer.

Ready to go to sleep?

I grew up with dogs, and I've just become a cat person for life, it seems.

So it turns out our cats are masters at finding their way

back to base.

But our next set of pets have hidden abilities

that help them keep track of us in their new domestic lives.

Our favorite pets' super senses evolved to help them survive in the wild.

But their pampered lives in our homes couldn't be more different.

Left home alone,

do our pets enjoy the peace and quiet of an empty house?

The truth is, our houses might not seem quite as silent to them

as they do to us.

That's because most of our pets share an ability

to hear ultrasonic noise way above our hearing range,

which only goes up to 20 kilohertz.

Dogs hear frequencies over twice as high as us.

And cats, four times higher still.

So, electronic devices like LED lights and quartz timers,

designed to sound silent to us

still emit high frequency noises that can be heard by our pets.

But they don't just hear higher pitches than us,

they hear over much greater distances too.

Claus' ears are so sensitive,

it's thought he may be able to identify sounds a mind-boggling distance

of two miles away.

So it means, in theory, he'll always be the first to know

his owner's on their way home.

It helps that his ears can rotate 270 degrees,

channeling even the tiniest sounds directly into his eardrums.

Strike's ears prick up later,

hearing us when we're around a quarter of a mile away.

His hearing is four times more sensitive than ours.

So it almost appears he has a sixth sense for when we're coming home.

In the garden, Titus hates to be left out.

He predicts an imminent arrival through low frequency sounds

rumbling through the ground.

It's his defense against predators,

but also means he gets to be first for once.

Orlando can see and hear us now,

but in typical cat fashion, he's not letting on.

His ears allow him to pinpoint tiny noises

two octaves higher than our other pets

and react ten times faster.

If he could be bothered. That's what makes him such a brilliant night hunter.

But of all the pets, only Strike can use his hearing as a superpower.

Within seconds, he tunes in to the sound of our heartbeat,

using it to gauge how stressed we are,

and changing his behavior in response.

And incredibly, his own heartbeat then falls into sync with ours.

Just one of the reasons we feel our dogs are so incredibly in tune with us.

But it's not just our furry friends that can surprise us.

Even our aquatic pets have hidden super senses.

And it turns out, our fish are surprisingly sporty.

This is the Guangdong province of Southern China…

…where some goldfish with the incredible ability to play soccer

have become an internet sensation,

clocking up four million hits

after their owner began broadcasting their matches on social media.

The man behind these unlikely global superstars is Mr. Yang.

He discovered their talents by chance

when trying to combine his lifelong passions,

goldfish and soccer.

The fish tank I designed

happened to be the proportion of a football field.

I wondered if I could train the goldfish to play.

I put a little ball in,

and soon they became interested in playing with it.

Gradually they got used to the game

and could even score.

I filmed a lot of their matches,

and their goal scoring moments are spectacular.

I put the videos on TikTok,

and they became an instant hit.

People were so surprised by these goldfish.

This unexpected talent for soccer

is thanks to a system of tactile sense organs called the lateral line.

Unique to fish, this ridge of sensory cells running down each side

help them spot predators by perceiving movement

and pressure changes in the water.

Which also comes in handy to sense exactly where the ball

and other players are on the pitch.

Each individual cell of the lateral line contains a tiny hair

called a stereocilia,

fish's version of a whisker,

which moves in a jelly-like substance called cupula.

Mr. Yang's goldfish are Ranchu,

an ancient breed originating from China's emperors.

A year into their training, they're more competitive than ever.

Little Red scores fantastic goals.

He is strong and gifted.

He is my favorite player.

His fans compare him to Cristiano Ronaldo.

The way he keeps scoring goals is amazing.

He is a very talented football player.

A sense of touch gives our pets a finely tuned appreciation

of the world around them.

But how does their eyesight compare to ours?

What can they see that we can't?

To find out, we've brought some pets to our own special art gallery.

Every one of them has highly specialized eyesight,

evolved for survival in their natural habitats.

So it turns out, we humans are only seeing part of the picture.

Birds and reptiles are tetrachromatic.

They have four cone cells in their eyes.

Most humans only have three.

So where we see a million colors…

they can see all the way into the brilliant fluorescence

of the ultraviolet spectrum.

This heightened appreciation of color helps them navigate

through dense forest and hunt tiny insects.

But it's also their way of attracting a mate.

Ultraviolet feather markings, invisible to our eyes,

come in very handy for getting the opposite sex in a flap.

It's a different story for our mammalian pets.

Strike is dichromatic.

His eyes have better night vision,

but with just two types of cone cells…

…bright colors barely register.

Instead, along with his mates, Strike sees the world as a series

of muted blues and yellows.

That's why our furry friends notice patterns rather than colors.

But dogs and cats' visual superpowers lie elsewhere.

As apex hunters, their eyesight has evolved

to spot the tiniest movements of their prey.

Especially in dim light.

Sorry, guys, it's only Leo.

Apart from dogs and cats,

most pets' eyes are positioned on the sides of their heads,

giving them a far greater field of vision than us.

But one outperforms them all.

Chameleon Michelangelo can see a full 360 degrees

and can also rotate and focus each eye independently.

Vision that's monocular,

meaning each eye sends a separate image to his brain.

So Michelangelo really does have eyes in the back of his head.

There's just no beating that, is there, Strike?

We always knew our pets were keeping an eye on us,

but some have an even more amazing tool for sensing the world around them.

For many of our pets, their impressive whiskers

are one of their most recognizable features.

Blue dumbo Stanley is friendly, intelligent,

and one the cleanest pets you can own.

Like all rats, he'll spend around a third of his waking hours

proudly grooming his whiskers.

And as the owner of around 70, each up to five centimeters long,

we're going to let him show us exactly what these super sensory hairs can do.

A fun maze, filled with textures and obstacles,

will be an action-packed way to give Stanley the whisker workout of a lifetime.

Fanning out from his cheeks, eyebrows, and chin,

they're his first point of contact with everything he encounters.

Even if it were pitch dark,

his whiskers would help Stanley build a detailed picture of his surroundings

and decide where he can squeeze…

and where he can't.

The closest human equivalent for the constant data provided by whiskers

is the mental map we compose in our mind's eye

when running our sensitive fingertips across the surfaces in a darkened room.

But now, the study of rats like Stanley is spearheading the intersection

of biology and engineering in medical science.

To explain, let's go back to the start,

and slow down the cameras even more.

It's only in this much detail we can appreciate

just how much Stanley is actively moving his whiskers.

Sweeping them forward in a whisking motion

to interact with the objects around him.

It's such a sophisticated system

that if macro-robotics companies could successfully replicate it,

it could lead to a revolution in keyhole surgery.

Which means that rats like Stanley here

may soon be helping to save human lives.

So, whiskers are truly wonderful…

…but our next pet's secret abilities can elevate them to new heights.

In rural Texas, Nick Phomkasornsri shares a six-acre ranch

with husband Steve, five-year-old son Wyatt,

and a growing menagerie of rescue pets,

all of whom benefit from his vision for their new lives

of almost total freedom.

Especially his feathered friends.

This is Torchy, and this is Klono.

Torchy is a harlequin macaw, and Klono is a military macaw.

Um, Torchy's about ten years old, Klono's only about three.

So every day I take 'em out, I let 'em go.

They love to fly.

Before he came to live on the ranch, Klono, like most pet birds,

had never been allowed to fully stretch his wings.

It only took four months.

He went from flying indoors, just maybe a little bit fluttering

from perch to perch,

to now, he's, like, diving around trees and everything.

The key to Klono's newfound aerobatic skill

is his natural impulse to flock closely

alongside experienced flyer Torchy.

Like fish swimming in shoals,

flocking is the super sense that enables birds to fly in close proximity

without colliding, even at incredible speeds.

It's been really cool to see him develop those flight skills.

Just twisting and turning, and diving under trees.

He… he loves it. He loves it.

Klono's flocking skills

are thanks to something called proprioception,

his ability to mentally gauge his body position relative to other birds.

Oh, he came up behind me. I didn't see him.

Whilst we humans also use proprioception

to gauge the position of our bodies in space,

birds take it to another level entirely.

I could watch him all day.

Airflow across Klono's wing tips

stimulates individual feathers, offering constant feedback

about his body position.

He can perceive the tiniest of changes in direction made by Torchy,

and fly just millimeters from his best friend.

Torchy, Klono!

Thanks to Nick, rescue parrot Klono gets to make the most

of his flocking superpower.

Come here, Klono.

Come on, Klono.

Klono, come here.

These birds have a phenomenal life.

I just feel so happy for them,

to be able to be doing what most captive parrots never ever get a chance to do.

Klono's powers give him a unique bird's eye view of the world.

But all our other pets share an extraordinary extra super sense,

which means they experience life in a way we can only imagine.

This all comes down to a cluster of specialist cells

buried deep in most pets' throats called the Jacobson's organ.

Their job is to detect airborne chemical particles.

Allowing all pets, except birds, that is…

…to pick up invisible information from every other living being they meet…

including us.

This incredible extra sense means they have the potential to save lives.

Barna.

Meet 22-year-old Emily Cook

and her very special dog Barna.

Barna is like a guardian angel because he's constantly watching over me.

He's not just my pet, I know that I'm safe while he's there.

Even in a situation like this where you've got the wind,

the sea, the beach, all these distractions,

I just know that he can come back to me and let me know when I'm gonna be unwell.

Until Barna came along,

Emily thought her chances of an independent life were long gone,

since being struck down by a mystery illness aged just 12.

I was a massively active young girl.

I was a competitive swimmer, I was doing really well at school.

Completely out of the blue, I was on the landing of my home,

and I went unconscious.

Then it just kept happening.

After years of tests, Emily's doctors attributed

the frequent blackouts

to a rare neurological condition.

But predicting them proved medically impossible.

I have no warning signs myself.

I have no awareness that it's going to happen.

It's just a constant state of anxiety.

Thinking, "Oh, what happens if I go unconscious here?"

"I'm crossing a road, what happens then if it happens?"

That's terrifying.

But salvation was just around the corner,

in the form of Hungarian vizsla Barna.

We got Barna as an eight week old puppy.

At that age, they're just loopy,

wrinkly, orange balls of fur.

And I just loved spending time with him.

He was a focus away from my health.

The pair quickly became inseparable,

and Barna was witness to every attack.

Whenever I was unconscious, he wanted to be by my side.

He'd often just lie there kind of staring at me,

I think waiting for me to wake back up.

But Barna was about to prove he could provide more than just comfort.

All of a sudden, he just came sprinting into the kitchen

and sat down in front of me.

He then did just a really, really intense stare.

And then a single bark.

And up until that point as a puppy, he never really barked at all.

And then five minutes later, I was unconscious.

Then it kept on happening every time.

Incredibly, Barna appeared to have a natural ability

to do the one thing Emily's doctors could not.

Predict her blackouts.

And it's all thanks to his Jacobson's organ,

which allows him to monitor microscopic chemical changes

in her breath and sweat, indicating an imminent attack.

Other dogs have been trained to predict epileptic and diabetic seizures.

Barna instinctively took it upon himself to alert Emily,

a skill he refined with 18 months training,

qualifying him as a registered assistance dog,

the first of his breed.

When I put Barna's uniform on, you kinda feel

a bit invincible at that point.

There's no words for how amazing his abilities are.

He's given me my life back,

and I don't think many pets, you can say, can do that.

I always get emotional when I talk about him, what he does… Um.

With Barna constantly by her side, Emily has rejoined the world,

safe in the knowledge that Barna will alert her before a blackout.

That five minutes has changed everything,

that, all of a sudden, I have the ability

to act before I'm gonna come unwell.

I can let people around me know what's going to happen,

so no one gets upset, no one starts panicking.

With no portable equipment

that can predict seizures currently available…

- Hi, can I get a latte, please? - Yeah, for sure.

…those without an incredible pet like Barna

would face a lifetime trapped at home.

My life's had a complete turnaround since Barna came into it.

I have the independence to go out on my own,

to go to places and locations like this

that I never could have dreamed of going before.

To thank him for her freedom, Emily's determined

to pay Barna back any way she can.

For Barna, coming to the beach, it's his favorite thing in the world.

That moment when you can just take off his working jacket

and let him run free along a beach,

just completely enjoying himself, that brings so much joy to me as well.

Barna.

Looking back at where I've come from,

it's just amazing the fact that the difference in my life,

I have hope,

I can look to the future, and that's something that just,

I didn't think was possible before.

The future is bright with Barna.

I just… I love him for it.

We've seen how our pets live in a heightened world

with super senses honed for survival in the wild.

And although pets like Strike,

Orlando…

…and Stanley

live in the safety of our homes,

understanding the potential of their super senses

not only helps us appreciate them more,

but adapt our lives to make them happier, healthier…

…and closer to us than ever before.

Next time, we reveal the super athletes living in our homes.

Ready?

Usually, he's just kinda flying at, like, a leisurely speed,

but when he wants to go, it's impressive.

And discover how our pets' wild past has given them

these incredible abilities.

It's a little bit of excitement and danger, all in the same time.

And I know a lot of people that have injured themselves.