♪♪ ♪♪ ♪♪ Narrator: Australia's largest land predator...

The dingo.

This "wolf down under" is one of an extraordinary wild family.

[ Growls ] The Canids.

One family... 37 different faces.

♪♪ From the smallest... ♪♪ To the tallest.

♪♪ The stealthy... And the formidable.

These are "Dogs in the Wild."

[ Howling ] ♪♪ ♪♪ Narrator: Wild dogs have many voices, and one of the loudest can be heard across the northern hemisphere, from the Himalayas... [ Howling ] ...all the way to the Arctic.

[ Howling continues ] The wolf.

The grey wolf and its 15 subspecies, including the Himalayan wolf, Mexican wolf, and Eurasian wolf -- are also the world's biggest wild dogs.

And one of the most formidable subspecies is the hardiest of all.

The Arctic wolf.

♪♪ Spending its entire life north of the tree line on the frozen Arctic tundra, the arctic wolf must be a jack of all trades to survive.

Males can weigh up to 130 pounds.

Wrapped in two layers of fur -- soft inner hair for insulation, and longer outer hair for snow-proofing -- wolves can endure intense cold.

They can also endure hunger: a wolf can fast for over two weeks.

♪♪ Young wolves go searching for mates, but if they don't find one, they soon return to the safety of their packs.

[ Howling ] ♪♪ On the open tundra, the howl from another wolf can travel ten miles.

Wolves can cover three times that in a day.

An old Russian proverb says, "The wolf is kept fed by its feet."

[ Wolves howling ] By following the howling, it soon re-joins its pack.

♪♪ Wolves must cooperate to survive, so pack-living Canids keep close eyes on each other.

The shape and markings of the wolf's face makes its eyes more prominent.

And with larger brains than domestic dogs, they can read the tiniest cues from their pack members' faces.

Along with plenty of eye contact, there's lots of talk.

[ Wolves howling ] Wolves howl together to strengthen the bonds within the pack.

[ Howling ] By communicating so effectively, they can work together to take on prey nearly 20 times their size.

A single wolf is an able predator; as a pack of seven or more, they are truly formidable.

[ Wind howling ] [ Animals squawking ] Wild dogs grow stronger when they work together -- especially in the rich diverse forests of Southern India.

Dawn is always a noisy time of day.

[ Animals calling ] ♪♪ It's a cacophony of sound.

[ Animals calling ] But part of the chorus comes from one of the most talkative wild dogs of all.

[ Grunting ] The dhole.

[ Chittering ] Dholes live in large packs.

The breeding male and female are in charge, overseeing siblings, young from previous years and new pups.

The extended family can be 15 strong... [ Yelping, squawking ] And they chatter constantly.

[ Yelping ] But the forest is noisy.

To make sure they're heard, the dhole use unique high-pitched calls, which break through the background noise.

[ Dholes calling ] Dholes have 11 distinctive calls, used for different situations.

At play, they whine and whimper.

But their talk's not just for fun.

Dholes are only the size of a border collie and share this forest with much larger, more intimidating creatures.

[ Dholes yelping ] The pack has discovered a scent-marked tree.

Their calls switch from whines to warning growls, chatterings and screams.

It could be the scent of an elephant.

A mother with young can be particularly hostile.

Or a more serious threat: leopards and tigers stalk these lands -- both can kill the smaller dhole.

♪♪ The family talks to each other as they scout the area.

[ Yelping ] When the adults declare it's safe, the youngsters resume their playful noises.

But one older sibling sits apart, acting as sentinel, ready to sound the alarm in case of danger.

With the coast clear, the adults scan the territory for food.

The forest is full of deer.

They can be twice as tall and many times heavier than a single dhole.

But if they work as a team, the pack can take them down.

And the dholes can use the dense forest to turn the odds in their favor.

A male chital with large antlers is more likely to get tangled in the thickets.

The dholes edge closer, talking to each other to co-ordinate their attack.

But their high frequency calls don't travel far.

The more the dholes disperse, the more they'll struggle to hear each other.

For a moment the pack's confused.

But these chatty canids have saved their best talk for last.

[ Sharp whistle ] The whistle.

[ Whistling ] A low frequency call that carries farther and is easier to hear through the thick forest foliage.

With up to ten of them surrounding the deer, the whistling hunters know exactly where every pack-member is, even when they can't see each another.

At last, they're all in place.

♪♪ ♪♪ [ Bark ] ♪♪ ♪♪ ♪♪ ♪♪ Gathered together, the dholes are at their most vulnerable.

A tiger or leopard could steal their prey, so the pack must eat fast.

With teeth like razors, dholes can consume a quarter of their own body weight in just 10 minutes.

Once he's had his share, the young sentinel is back on duty, listening out for trouble.

Finally the talkative dholes can rest easy.

♪♪ ♪♪ ♪♪ ♪♪ ♪♪ At the top of the world, over 16,000 feet above sea level... the rugged peaks of the Himalayas meet the stark Tibetan plateau.

♪♪ With biting winds and lurching temperatures, the weather can turn in an instant.

But one extraordinary wild dog is built for this inhospitable landscape.

The world's highest dwelling fox -- a shape-shifter who can hide in plain sight.

The Tibetan fox.

♪♪ The fox family evolved before their wolf cousins.

They're smaller, with longer snouts and fluffier tails.

This Tibetan fox lives exclusively on these harsh, high-altitude plateaus.

♪♪ ♪♪ Too small to hunt large animals, she targets smaller prey...

The pika.

These hardy relatives of the rabbit make up 95% of her diet.

But highly alert to danger, they're no easy catch.

♪♪ She must be stealthy.

There's no cover -- the conditions are too harsh for trees to grow.

But her angular, oversized head may give her the edge.

She blends in perfectly with the landscape, peering unnoticed over rocks.

♪♪ Using the natural contours as cover, she edges closer.

If the pika spots her, it will raise the alarm.

♪♪ There can be dozens of pika living underground.

The fox must be patient.

♪♪ ♪♪ ♪♪ One pika a day is enough to feed her...

But recent events have increased the pressure.

♪♪ [ Kits whining ] Three kits, barely two months old.

♪♪ ♪♪ ♪♪ Like all youngsters, they're very demanding.

While nursing, their mother must eat more to support her family.

The kits will rely on her for several months as they progress from milk to solid food.

It's a relentless schedule...

But help is at hand.

This is the kits' father.

Tibetan foxes pair up for the breeding season, and the male shares the work of parenthood -- watching over the pups and hunting.

By digging and listening at pika burrows... Tibetan foxes drive their prey into the best place to strike.

Although he's so focused on his work, he's missed a prime opportunity.

♪♪ And he may have bitten off more than he can chew.

♪♪ But the Tibetan fox's remarkable face makes all the difference.

Their long, narrow snouts can probe deep down into the burrows.

He returns with provisions.

Vital supplies to share with his mate.

♪♪ ♪♪ The parents must both hunt often to support their growing family.

♪♪ ♪♪ ♪♪ Thanks to such dedicated parents, these kits have the best chance of survival.

Striking looks... and shrewd teamwork: the perfect combination for life on top of the world.

And they're not the only fox with a striking feature.

Stretching thousands of square miles across Southern Africa, the remnants of a vast ancient lake have baked dry over millennia.

The salty, clay crust that remains forms the imposing Makgadikgadi Pan.

Brutal and exposed, there's nowhere to hide.

Survival out here demands, being highly alert at all times.

And one resident wild dog... is all ears.

The bat-eared fox.

These ears are serious hearing hardware...

Some five inches high and larger than their own faces.

From the safety of their den, they monitor their surroundings.

Bat-eared foxes live in pairs.

This isn't just for breeding, it's also for security.

Two pairs of ears are better than one.

Listening out for danger, the batties decide the coast is clear.

Now, to head out on the hunt.

♪♪ Bat-eared foxes are insectivores -- but in the harsh midday sun, most insects have vanished underground.

So they use their supersized ears to tune in on the slightest sounds.

The foxes are not the only ones on the hunt.

[ Animals calling ] They share the pan with a larger, more intimidating cousin of the wolf: the black-backed jackal.

Twice their size... with teeth that can crunch through bone... jackals are their biggest threat.

Jackals hunt in the same territory and will even kill bat-eared foxes.

For now the jackals have other things on their minds: a springbok.

Working together, they torment their prey until it collapses through exhaustion.

♪♪ The bat-eared foxes know that more jackals will soon be attracted.

They'd better return to the safety of their den.

♪♪ ♪♪ ♪♪ With nightfall -- and well-fed jackals dispersed -- the batties head out again.

♪♪ ♪♪ Now, to search for insects in the dark.

♪♪ And they're not alone.

Rather than defending their hunting field, bat-eared foxes let their territories overlap.

Higher numbers increase their chances against marauding jackals.

By carefully turning their heads and ears side to side, the foxes pinpoint the tiniest rustlings below.

A treasure trove is soon discovered.

Northern harvester termites construct elaborate tunnels underground, emerging through small vent holes to forage for grass.

But the foxes' incredible ears can pinpoint these tell-tale rustlings.

A single bat-eared fox can consume over one million termites each year.

♪♪ Fortunately, there's enough to go around: just over half a square mile can contain over 300 termite nests.

♪♪ A young fox is out foraging alone.

A fox without its mate is vulnerable.

♪♪ And the black-backed jackals are in the neighborhood again.

[ Jackals barking ] ♪♪ The smaller fox raises its tail to look as large as possible.

♪♪ ♪♪ This threatening pose works for the moment.

She might not be so lucky next time.

♪♪ A lone bat-eared fox won't be left alone for long.

♪♪ Threat posture at the ready... but it's another fox!

Its likely been trailing her for some time.

♪♪ A further benefit of overlapping territories is the ability to find a mate.

♪♪ Now that they've found each other, these two foxes will stay together.

♪♪ And together, bat-eared foxes have a better chance of facing whatever comes their way.

♪♪ ♪♪ Wild dogs live on nearly every continent on the planet.

But one continent -- South America -- is home to 10 species that have evolved independently from their fox and wolf cousins.

These unique canids are among the family's most diverse, thanks to their broad diet and ability to adapt to the continent's many habitats.

This is the bush dog, a pack-living dog that has webbed feet to hunt prey in the flooded forests of the Amazon.

On the grasslands, the hoary fox's small teeth and short muzzle are perfect for catching insects.

Under 20 inches long, the tiny Darwin's fox only needs a small forest territory to sustain it.

While up in the peaks of the Andes the wolf-like culpeo is built to endure the harsh terrain.

♪♪ South America is also home to possibly the wild dog family's most unusual cousin.

The maned wolf.

♪♪ Standing over three feet tall at the shoulders, this gangly creature is the tallest wild dog on the planet.

Despite looking like a fox on stilts, they are genetically neither fox nor wolf.

They are the only remaining member of a long extinct line of South American canids.

♪♪ Their distinctive manes may have evolved as a warning to other larger rivals.

Isolated in this landscape, the maned wolf helps unlock the savanna's potential for life in their own very particular way.

With a territory of up to 50 square miles... long legs allow them to glide across the savanna on the search for food.

And true to their unusual nature, this is no ordinary wolf diet.

Rather than just eating meat, the maned wolf has a penchant for the lobeira.

This large, tomato-like fruit thrives on the savanna.

They enjoy lobeira so much, it's aptly named "fruit of the wolf."

Some believe it's medicinal and protects them from deadly kidney parasites.

Fifty percent of their diet is fruit -- more than any other canid.

♪♪ As they mark their territory, maned wolves leave droppings that contain hundreds of undigested seeds.

They can disperse these seeds dozens of miles from where they fell.

For the moment, the seeds are exposed under the baking sun, but they won't stay here for long.

♪♪ Leafcutter ants are drawn to bits of fruit that remain on the seeds.

♪♪ The seeds are carried back to the ants' nest, stripped of fruit and discarded.

♪♪ But this sheltered, humid spot provides the perfect growing conditions.

In parts of the most pristine savanna, lobeira fruit seedlings can be seen growing only around leaf cutter ants' nests -- a guaranteed future larder for the maned wolf.

[ Barks ] The maned wolf: neither fox nor wolf, long-legged gardener, and an ant's best friend.

♪♪ Not every wild dog has such a well-stocked pantry on its doorstep.

Others must contend with a much harsher challenge to survive.

♪♪ The Sahara smothers 6% of the world's land.

Some 3.6 million square miles -- the size of China.

♪♪ ♪♪ Yet this vast, unforgiving place is home to the world's smallest wild dog.

The fennec fox.

♪♪ Barely more than a foot long, this tiny fox goes head-to-head with the desert every day.

The Sahara's filled with millions upon millions of grains of sand, and every grain acts as a radiator.

Sand absorbs heat, and the hotter it gets, the more heat it radiates.

The temperature here often spirals to over 100 degrees.

In such sizzling conditions, the fennec's size matters.

A small body can shed heat faster than a large one.

And to lose heat even faster, the fennec's ears act like sophisticated air conditioning units.

The network of veins cools the blood to lower the temperature.

Despite such capable cooling, not even a fennec can endure the heat of the Saharan sun.

There's no shade, but fennecs are masters of their environment.

Moisture concentrates at the foot of the dunes, so the sand here is firm enough to dig a burrow.

Home sweet home for a pair of fennecs.

♪♪ They have shelter from the worst of the heat, but they must eventually leave the safety of their den to find food.

♪♪ And this enormous desert is a dangerous place for a tiny wild dog.

An unwary fennec is small enough to be caught by feral dogs and even eagle-owls.

But their sand-colored coats make them less conspicuous.

In the fading light of dusk, she makes a run for it.

Zig-zagging... and jumping... She uses the dunes to mask her location.

The grains of sand are constantly shifting but the pads on her feet are furry for maximum traction.

Few can keep tabs on her whereabouts.

♪♪ But with night falling, the heat-radiating sands turn cold.

♪♪ Temperatures plummet to below freezing.

The sudden cold is potentially worse than the heat, but the fennec's inner coat is insulated.

Set for the night, she can search for food.

Small bodies don't need much, and by being omnivorous, fennecs can find enough to eat.

Insects, berries, roots -- every scrap is on the menu.

There may be food, but there's no water.

Thankfully, her kidneys are so efficient, she's the one dog that doesn't need to drink.

She can get all the water she needs from the food she eats -- even the tiniest spider.

The fennec evolved as the desert first appeared, four million years ago.

No other canid can so completely endure the challenges here.

So this smallest of wild dogs is not only built for this harsh desert... She's the only one to have tamed it.

Wild dogs are no strangers to life at the margins.

To survive, they must adapt to whatever challenges come their way.

One of the family's most adaptable lives in Australia.

The dingo.

The fate of one particular family of dingoes on K'gari Island in eastern Australia has been closely monitored.

K'gari means "paradise"... 74 miles of ancient forest surrounded by sandy beaches.

Isolated from the mainland, these dingoes appear to be living the dream.

While dingoes on the mainland have interbred with domestic dogs, the more purebred dingoes can be heavier, with pale sandy coats, as well as white markings on their chests, tail tips, and feet, called socks.

And these wild dogs are a breed apart.

Their wedge-shaped skulls have longer, sharper canines than domestic dogs.

And unlike their domestic cousins, dingoes only breed once a year.

These "wolves down under" are quite the family.

The pack has a pair of breeding adults, sub-adults from previous years, and juveniles.

♪♪ Being top of the food chain, they enjoy prize pickings from the forest.

And nothing is off the menu.

[ Howling ] Life may be good for dingoes in paradise, but their luck can quickly turn.

Summer fires are a natural part of life on K'gari.

Many plants have adapted, and the clear-out will trigger a rush of new growth.

But with climate change causing the forest to grow drier, recent fires have become more devastating.

Unable to rely so much on the forest, the dingoes must look elsewhere for food.

The juveniles will soon leave the pack to lead solitary lives until they find suitable mates.

♪♪ So they need to be strong enough to go it alone.

♪♪ ♪♪ To see them through, the dingoes resort to beach-combing.

♪♪ Life on the beach is a lottery.

A solitary crab won't go far.

But the surf has brought them something special... A dugong carcass.

When there are fewer opportunities, the juveniles always get the last dibs.

And it's even harder if no-one's in the mood for sharing.

[ Barking ] The carcass isn't around for long.

As the tide rises, the promise of a banquet dwindles.

Rare events like this won't be enough to sustain the family long term.

But throughout the fire season, one natural event can make the difference between life and death.

♪♪ ♪♪ Every summer, turtles appear on the beach.

♪♪ Nesting between three to five times per season, they each lay an average of 115 eggs.

There can be 200 females nesting along these beaches... and many thousands of eggs.

These hidden treasures could be a lifeline for the dingoes...

If they can find them.

Dogs are armed with a super-sense of smell.

Their highly sensitive noses have 290 million more receptors than a human's.

They sniff out a nest and start digging.

With slender muzzles that are longer than those of domestic dogs', and jaws which open wider too, they are perfectly built for the job.

Throughout the worst of the island's fires, digging for turtles' eggs saved the dingoes from starvation.

The dingoes fed well... but thousands of hatchlings will still survive.

And when the time comes, the very presence of the dingoes might even benefit the hatchlings.

As the apex predators, dingoes keep the numbers of other creatures on the beach in check.

♪♪ This dingo pack limits the overall impact of predation on these young turtles.

♪♪ And as a result, enough turtles will survive to reboot the cycle and return to this beach in future years.

♪♪ ♪♪ Only dingoes in the north of K'gari have learned to exploit the seasonal abundance of turtle nests.

They have more offspring and larger pack sizes.

And the juveniles have a better chance of surviving to adulthood.

Some might even remain with the pack to help baby-sit the younger pups.

♪♪ These most adaptable dingoes have surely earned their place in paradise.

♪♪ ♪♪ The most successful wild dog of all has become so widespread, it extends from the Arabian Peninsula... to the Arctic tundra.

Yet, it's equally at home in the lush countryside of central Europe.

And in the last century, it's made the city its ultimate domain.

The streets of London now resound to its call.

[ Fox barking ] The red fox.

The world's most resilient wild dog.

♪♪ These two foxes, known as Vince and Bitey, are seven months old.

Their mom's raised four litters before, and thanks to her experience, the pups have grown strong.

But the pups' days under their mother's wing are numbered.

It's time to master life alone in the big city.

[ Growling, barking ] Vince is already familiar with some of the challenges ahead.

His ear was likely lost in a fight with another fox.

His sister Bitey is one of the smaller ones in the litter, but she too must find her feet.

To survive, these youngsters must raise their game above their country cousins, and become "super foxes."

Traffic is a deadly threat.

A third of city foxes have scars to prove it.

In open fields, a fox can reach almost 30 miles per hour...

But city foxes must be agile too.

Vince is quick and agile on the streets... but traffic's just one of many challenges foxes face in the urban jungle.

When you're around a foot and a half high, every wall is a potential fortress.

But with lightweight bones and long tails to counterbalance, foxes are exceptional athletes.

Vince can jump four times his own height -- the same as a six foot wall.

It's more of a struggle for Bitey.

She's just a bit smaller, and injuries are an occupational hazard.

But once the terrain is mastered, foxes can turn the vertical landscape to their advantage.

Using hidden routes across walls and fences, Vince vanishes and reappears in an instant, always keeping his distance from humans.

Like cheetahs on the savannah, foxes use vantage points to scope out opportunities.

♪♪ The ability to eat rotting food has allowed foxes to colonize urban areas.

♪♪ Nothing goes to waste... Caching supplies in hidden spots, urban foxes can be very resourceful.

♪♪ Car hoods are the perfect place to stash leftovers.

Cars are often parked longer in cities, so this is smart.

♪♪ ♪♪ ♪♪ City streets are regularly cleaned, so urban foxes urinate more than their country-dwelling cousins to mark their home turf.

But Vince and Bitey's elaborate sign-posting hasn't gone unnoticed by another fox.

A new vixen has arrived, and she wants this territory too.

Foxes avoid physical confrontation where possible, but she has other ways to show the pups who's boss.

She postures and scent marks around Bitey to display dominance.

But Bitey's not backing down.

[ Snarling ] It's time for the ultimate test of strength...

The foxtrot.

♪♪ They size each other up, opening their mouths to intimidate their opponent.

♪♪ Bitey has stood her ground... but this new vixen isn't deterred.

She spots Vince.

♪♪ These shows of strength will determine the pecking order around here.

♪♪ ♪♪ ♪♪ ♪♪ ♪♪ Vince and Bitey may have held onto their turf, but the new vixen has proved she's strong enough to stay here too.

There are 10,000 foxes living in London, so encounters like these will be a regular part of life for the youngsters.

But city foxes often learn how to get along, so they can all eke out a living in the same neighborhood.

♪♪ The resilient red fox copes so well in the city, it can call the streets of London home.

♪♪ ♪♪ Next time... as they live across the planet and find so many ways to survive...

There are still more secrets to wild dogs' success.

♪♪ ♪♪ ♪♪ ♪♪ ♪♪ To learn more about what you've seen on this "Nature" program, visit PBS.org.

♪♪ ♪♪