Sorry, this video is not currently available.

Full EpisodePets: Wild at Heart | Episode 2 | Secretive Creatures

From the award-winning team that brought us “EARTHflight” and “Penguins: Spy in the Huddle” comes a revolutionary look at our pets. Our pets may seem familiar but they exist alongside us in a secret world of wild behavior and natural abilities that we hardly recognize. This two-part series explores this parallel existence with all the techniques that have been perfected in past “spy” shows, including HD spy cameras, night vision cameras, drones, miniature on-board cameras and digital high-speed cameras.

In a program packed with incredible filming techniques, from Schlieren photography that makes smells visible, to moving X-rays, ultra slow-motion, and ultraviolet vision as well as HD horsecams and doggycams, discover how our pets experience the world through their astonishing senses and hidden channels of communication. Includes the sensory secrets of budgies, horses, guinea pigs and goldfish as well as the remarkable abilities of hamsters, cats and dogs.

Transcript Print

♪♪ ♪♪ NARRATOR: Every day our pets engage in behavior that's familiar to us.

NARRATOR: But why do hamsters love to run on a wheel?

What makes a rabbit hop?

How does your dog understand the rules of the pack?

It's because our pets, though tame for thousands of years, were wild animals for millions more.

To reconnect with that wild side, our pets play.

And their games require some extraordinary senses and special skills.

Now, with spy cameras and moving X-rays, filmmakers have captured the hidden powers of our pets.

You'll never look at them the same way again.

[Theme music playing] NARRATOR: All our pets possess an array of wild senses, and this hamster is about to use his on a secret mission.

He has waited until the dead of night, while the rest of the household is sleeping.

♪♪ Although not exactly the best of climbers, instinct drives him on.

To avoid predators, he travels by night, a time when his eyesight comes into its own.

But he also uses his impressive whiskers to build up a 3D picture.

He uses sounds pitched above our hearing, and his supersensitive nose analyzes every smell.

These senses help him create a sensory map that, in the wild, would guide him across miles of featureless desert.

But his navigational equipment doesn't stop there.

Wherever he goes, glands on his belly lay down a scent that leaves a trail, allowing him to retrace his steps back home.

For a burrowing creature, holes are irresistible.

In a hamster-ball, he's astute enough to control direction.

♪♪ Although some aspects of our modern world are too challenging even for this hamster.

But his incredible senses can also get him out of trouble.

Using high-pitched calls that we can't hear, he detects the drop by the sound of the returning echoes.

Disaster averted, he continues his secret mission -- one he must complete before daybreak.

♪♪ For dogs, too, getting out and about excites their wild senses -- and for such intelligent animals, you can't beat a road trip... While we are obsessed with visual landmarks, they focus only on scents.

We have a measly six million smell receptors, but a dog's nose contains 300 million.

They use it to unravel stories about the world around them.

Predictably, most are about food.

Forty times more of their brain than ours is devoted to deciphering smells.

They home in on those with special significance.

A single aldehyde -- a chemical compound found in blood -- makes this one-time hunter drool.

There is a way to bring this smelly world to life.

A technique called Schlieren photography visualizes the air currents that carry odors and shows the remarkable workings of a dog's nose.

Dogs breathe out through the side slits in their nostrils.

As the expelled air rotates, it helps draw more scent into the nose.

This two-way current helps a dog gather scent almost continuously.

But that's not all... A male can smell a female in heat at concentrations of one part in a trillion.

♪♪ Licking helps capture more of her alluring scent.

His tongue takes the odor to a second smell organ in the mouth that's hardwired to the brain and tuned to these sexual pheromones.

It's love at first sniff.

[Whimpers] For dogs, being a passenger rivals any wild experience -- but it can be tinged with disappointment, too.

The streets of Paris may be full of romantic promise... But pet dogs are seldom in control of their destiny.

[Barking] Love may be in the air, but it's so rarely fulfilled.

Cats are freer to follow their noses... and they've been shown to investigate several hundred odors in an hour.

Smells can sometimes take them to a drug-fueled gathering.

He can detect the scent of catnip in just one part per billion.

Just a few bites of this mind-altering plant and he falls under its alluring spell.

Its volatile oils imitate a sexual hormone and cause a potent reaction in his brain.

Eight out of ten adult cats find it totally seductive, and this response is genetic.

Even big cats, such as leopards and tigers, react in the same intoxicated way.

For cats, catnip may be a recreational drug but it's totally harmless... although there are always some who overindulge.

[Meows] ♪♪ It's not all peace and love.

Cats are solitary by nature and don't like sharing.

After about 10 minutes, the cats come back down to earth.

Yet a cat's nose is not its primary sensory tool -- its eyes are highly tuned to fast-moving prey.

♪♪ Fish are mesmerizing -- especially those that are tantalizingly out of reach.

Goldfish have their own extraordinary abilities.

They appeared in China over a 1,000 years ago, having been selectively bred from wild silver carp.

Around 250 years ago, the Stargazer appeared.

Legend has it they were created so that their eyes would always be directed in wonder towards the glorious emperor.

Experiments have revealed that goldfish recognize their owners.

They have surprisingly good memories, too -- five months or more.

Their extendable jaw helps suck up food.

The edible bits are ground-up by tiny teeth at the back of the mouth, while the rest is spat out.

The Stargazer's protruding eyes are easily damaged, so they should only be kept by specialists.

Even so, goldfish have astonishing powers of regeneration, and an injured eye can regrow.

Goldfish see 'far red' -- a color we can't see, that penetrates murky pond water.

But it's not their only sensory tool.

A row of sensors known as the lateral line picks up water movements.

The filming technique that visualized airflow can also show the eddies created by a swimming goldfish.

These mini-currents are detected by the lateral line of other fish and this helps them swim as a coordinated school.

It perceives predators, too -- a touch sends a warning shockwave.

Goldfish even use ripples to flirt.

♪♪ [Meows] Just as our pet fish can detect water currents, our favorite pet birds can sense the movements of air.

A parakeet responds to surrounding air currents by adjusting and controlling her flight.

Nerve endings at the base of her feathers continually feed back the information she needs.

In this way, she detects and avoids turbulent air... And seeks out rising currents.

By sensing the air, she maintains flight efficiency.

And parakeets have yet another sensory secret... In their courtship, good looks are everything.

But after her flight, she's too occupied in preening to care.

But her admirer has ways to get himself noticed.

She sees more subtleties of color than we can, and she detects ultraviolet, too -- a color invisible to us.

Under UV, his plumage takes on a very different look.

The yellow pigments in his crown and cheeks absorb UV, and the effect is stunning.

But unless she looks, it's all in vain.

He fluffs up his feathers to show off his true colors, but she still gives him the cold shoulder.

It seems every relationship needs a nudge sometimes.

Now, he has her attention!

Females prefer males that really shine -- the more his plumage absorbs UV, the fitter and healthier he is.

She's impressed -- and invites him to preen.

The parakeet's sensory world continues under our radar -- as it does with so many of our pets.

The wandering hamster is completing his secret quest.

It's taken half the night, but he's found exactly what he's looking for... He stuffs his cheeks with as much as he can carry.

And he can carry a lot.

But there's still one remaining challenge -- to get back to his nest!

It's no mean feat.

By using the mental map he created on his outward journey, he sets off in the right direction and soon picks up the scent trail he previously laid.

♪♪ Then, it's a matter of following his nose to his cage.

Wherever a hamster lives, there's no place like home.

And as in all homes, there is always room for improvement.

His pouches are designed to keep their contents bone dry.

His new bedding is as fresh as when it was gathered.

Soon, thanks to his wild senses, this escapologist will be tucked up in his newly made bed with his owner none the wiser.

Hamsters can go about their business unnoticed, but some pets demand a more hands-on approach.

Anyone who owns a horse is in a unique relationship.

At its heart are the signals and senses a horse uses in the wild.

When a child grooms her pony, she unconsciously gives a message all horses understand.

The moving brush mimics the teeth of another horse and it's a sign of friendship.

Horses only groom close relatives or their very best friends.

Nibbling the base of the neck lowers the heart rate and has a calming effect.

Friendships create harmony in a herd, but they take time to maintain, so horses rarely have more than three lifelong friends.

To become a successful friend to a horse, a human must be in tune with a horse's wild ways.

When a mare's about to give birth, her knowing owner often separates her from the herd.

As a prey animal, she feels vulnerable at this time.

She waits until there is no one around, just as wild horses wait until there are no predators.

She then prepares the ground for the birth.

It's a dangerous time for the mare.

Foals are born fully formed and can be difficult to deliver.

In the end, it happens quickly.

In these first precious moments, the mare learns her foal's scent and creates a lasting bond.

She knows he must get to his feet as quickly as possible -- wild predators could be lurking.

He has to take his first steps within minutes and become fully mobile over the next few hours.

♪♪ He even tries to run -- a vital survival skill.

As he suckles, he bonds to his mother's distinctive scent.

Soon the world outside beckons.

He's ready to put those fragile legs to the test.

As his confidence grows, he practices kicking imaginary predators.

Young foals must quickly learn the rules governing horse society -- even rolling has its own etiquette.

Foals must roll their mother.

There are even rules on dealing with flies -- an annoying problem through the summer months.

To fight the onslaught, horses are equipped with flywhisks, but they are most useful for helping others, such as her foal.

So, the mothers are driven to distraction while their foals are kept relatively fly-free.

The foals must learn that it's horse manners to stand end to end.

He might not have grown the perfect flywhisk yet, but at least he's making the effort.

Learning to empathize is important for making friends --