[police siren wails] NARRATOR: The world's wildlife is on the move.

Pioneering new migrations... and joining the daily commute in and out of our cities.

They face unfamiliar dangers... [♪♪♪] as they strive to get just what they need to survive.

[♪♪♪] With one foot in the wild and one in the city.

They are fast becoming wild commuters.

Joining the many animals carving out a life in the newest and fastest growing habitat on the planet.

A land of opportunity.

However this unnatural world presents unique challenges.

[dogs growl] But for those able to adapt and take advantage of all that cities have to offer, the urban jungle is quickly becoming the new wild.

[police siren wails] [cell phone rings, vibrates] NARRATOR: The daily routine.

[clock clicks] Wake up.

Get up.

Go to work.

[♪♪♪] Over a billion people across the world commute into cities every day.

All in search of their pot of gold.

[train breaks squeal] But they're not the only ones.

[pigeons cooing] The world's wildlife is following suit.

Be it by land, underground, or by air, animals are traveling in to the world's cities seeking their own fortune.

[pigeon coos] PA: Please mind the gap between the train and the platform.

NARRATOR: They are becoming... wild commuters.

This female African penguin is guarding a nest in the most surprising of places.

[♪♪♪] A back yard.

[birds chirping] In one of the biggest cities in South Africa.

It's breeding season, and for just two short months she and her life-long mate leave the wild, joining other penguins to nest inside Cape Town, where the hustle and bustle keeps predators away.

It's a vital sanctuary.

The African penguin population has dropped by 80% in the last 50 years.

But the city doesn't fulfill all of their needs, so each day they take turns making the short hop back to the sea to catch fish.

[water bubbling] [♪♪♪] While the other patiently guards the nest.

Today though, this female's wait is almost over.

Her other half has come ashore on the nearby beach.

[penguins squawking] But first, he must find his way back to her.

Though his group, known as a waddle, decide it's too risky to return immediately and bide their time on the beach.

[penguins squawking] But, in no mood for delays, another waddle heads straight into the city.

[♪♪♪] Penguins are more accustomed to hopping over boulders than stairs but the same skills seem to apply.

[♪♪♪] [penguins squawk] [♪♪♪] They stick together for safety.

In the ocean they are at risk of being killed by great white sharks.

But traversing the city, they face something potentially even more dangerous: [♪♪♪] cars.

[engines revving] And the penguins have hit rush hour.

[♪♪♪] The only way back to the nest is on the city's roads and sidewalks.

[car horn honks] [engine revving] Stressed and disoriented by the hectic streets [penguin squawks] the group scatters.

[♪♪♪] [penguin squawks] Some take shelter in the roadside vegetation; others duck for cover in the drains.

[loud squawking] While a few lose their way completely.

[penguin grunts] [penguin grumbles] Separated from both their group and their partners, they'll soon realize that this isn't a long-term solution.

[penguin grunts] [waves lapping] Meanwhile back on the beach, the second group is getting some unwanted attention.

[penguins squawk] But experience has taught them that a successful commute is all about timing.

They've been waiting, for the sun to set.

[distant traffic] [waves lapping] With eyesight adapted to see in the dark depths of the ocean [loud squawking] they're well equipped to perform a night raid.

[♪♪♪] [♪♪♪] Sneaking in under the cover of darkness is easier.

[♪♪♪] But their black and white aquatic camouflage can work against them in the city.

- [brakes squeal] - [horn honks] [engine idling] Up to 30 penguins die each year on the roads.

But these practiced commuters know their way around the city.

[♪♪♪] Joining forces with the scattered members of the first group, they find their way back to their partners.

[squawking] After a long day, the couple is finally reunited.

[penguins squawking] And soon there'll be another mouth to feed, a precious addition to this endangered population.

[♪♪♪] These African penguins have found that Cape Town provides a vital element that's missing from their wild lives: a safe place to nest.

With relatively easy access to their fishing grounds.

The best of both worlds.

[♪♪♪] Which is what all commuters strive for.

[distant traffic rumbles] Across the globe other animals are also finding that the city can offer opportunities that are harder to come by in the natural world.

[wind howling] And in the barren Negev desert, in the heart of Israel, [♪♪♪] there is one individual who is running late for a date.

[♪♪♪] This three-year-old male Ibex was left behind when the rest of his herd made their daily commute into the nearby city.

[♪♪♪] [birds chirping] Ibex are expert mountain climbers.

[dog barking in distance] And their specially adapted hooves and keen sense of balance enable them to traverse the urban landscape with ease.

[birds chirping] They've come to Mitzpe Ramon for an easy meal.

[engines revving] The human residents have irrigated the land and created a green oasis.

But the young male has extra motivation for his commute today.

[♪♪♪] Breeding season is a very short one for Ibex.

Each female will only be in season for one day each year.

[♪♪♪] So there's no time to waste if he wants to have any chance of mating.

[♪♪♪] Mitzpe Ramon is a sharp contrast to the serenity of the surrounding desert.

[♪♪♪] But with twice the normal amount of testosterone in his blood, he has a one-track mind and won't be distracted.

[♪♪♪] His arrival seems to have piqued the interest of some of the females.

But he takes it in stride.

You don't want to rush when you're trying to impress.

[♪♪♪] He singles out females in season using a special sense organ in his mouth.

[panting] [ibex grunting] His first advances are not met with much enthusiasm.

[ibex grunts] Nor his second.

Or third.

What's more, he's not the only male who made the trip into town today.

There are bigger, stronger, more experienced bucks here looking for love.

[inhales deeply] [♪♪♪] And they have the jump on him when it comes to wooing females.

This tongue waggle, part of his courtship display, apparently makes this older buck irresistible.

Though, ultimately the females will decide that.

Undeterred, the young male keeps trying his luck.

[♪♪♪] His behavior has not gone unnoticed and won't be tolerated.

[♪♪♪] Fully grown male Ibex have the biggest horns of their kind.

Evolved to pack a mighty punch.

[♪♪♪] [grunting] Half the larger male's weight and with considerably smaller horns the younger male concedes defeat.

His attempt to mate has been foiled by one of his own.

[car alarm activates] It's an important lesson on the road to maturity.

And while the victor lets off some excess steam, [alarm blaring] the young rookie returns to the desert alone.

[wind howling] The next day the young male is back but this time he's just concentrating on bulking up.

[birds chirping] Maybe next year he'll be a contender.

A place to eat is often easier to find in the city than in the wild.

And while some commuters seek out what we grow and nurture, others are more interested in what we throw away.

[♪♪♪] Like many cities, this busy ski resort in Colorado is a hot bed of fast food.

[♪♪♪] And as night falls, a group of very hungry animals enter Aspen, in search of leftovers.

[traffic rumble] Black bears.

[bear growls] Every night during the fall, they commute in from the surrounding hills on a hunt for takeout.

[♪♪♪] Most Aspen residents keep their trash secure.

But these trash cans are no match for a bear weighing up to 240 pounds.

[♪♪♪] When winter arrives they will begin a six-month hibernation during which they will eat nothing, so they need to pack on the pounds now.

To have any chance at surviving through the winter they must eat more than 20,000 calories a day.

[♪♪♪] With a sense of smell a hundred times better than ours no wasted food goes undiscovered.

[♪♪♪] [♪♪♪] [sirens wailing] Come morning the destruction caused by the bears' night raids is clear to see.

POLICE RADIO: One forty four.

Taking a report of a bear wandering in the back yard... NARRATOR: Sergeant Charlie Martin is the Aspen police force's wildlife officer, and the first port of call for bear disturbances.

CHARLIE MARTIN: Bears have done a lot of damage over the years.

[siren wailing] They like to get into cars.

They're pretty clever and they have learned how to open the door handle on a vehicle.

[♪♪♪] CHARLIE MARTIN: It will rip the door panels off, the interior, it will leave a present usually in there.

[♪♪♪] It's very unpleasant.

NARRATOR: And their havoc doesn't end there.

POLICE RADIO: One forty-four tech one.

NARRATOR: In Aspen they're responsible for more house break-ins than human burglars.

[indistinct radio chatter] In fact, black bears are using their wild skill set to get their dexterous paws on anything they can.

[random piano keys play] [bear grunts] [laughter] No door is left unopened.

[man screams] - WOMAN: Oh my... - [car horn honks] come on bear, move!

Oh my God!

NARRATOR: It can be upsetting for the people involved, but the black bears are simply following their noses.

For them, it has been a very successful commute.

With the arrival of winter they're well fed and ready for hibernation.

[grunts] The bears vacate the streets.

Most human residents can breathe a sigh of relief.

[♪♪♪] But not all.

[♪♪♪] In recent years, a few shrewd bears have decided not return to the wild.

But to hibernate under people's properties instead.

[♪♪♪] The bears rely on sheer audacity to get into the city but for the majority of commuters it's about playing by the rules and working hard to get what they need to thrive.

[♪♪♪] Just like the more than three million people who commute to work in England's capital each day.

[♪♪♪] Busy people with busy lives.

But there is one very important Londoner who can truly say that she is the busiest of them all.

[♪♪♪] A queen buff-tailed bumblebee, weighing just a twentieth of an ounce.

[♪♪♪] It's February and she's emerging from a five-month hibernation.

[children playing in distance] To make the most of what London has to offer, she must raise her own army of commuters.

[♪♪♪] First things first, she needs to find a base.

[♪♪♪] London is not an easy place to find a home but luckily there are still a few hidden gems fit for a queen.

[♪♪♪] Tucked away, dry, and well insulated with plenty of space for her growing family.

[♪♪♪] This will do nicely.

[♪♪♪] As the rhythm of daily life continues on London's busy streets, [♪♪♪] the queen stays at home.

Laying eggs that hatch into grubs [♪♪♪] that then emerge as worker bees.

This is the queen's army and it's tasked with a very important mission: to find food.

[♪♪♪] On the face of it a seemingly impossible job in the city but like most cities, hidden away behind London's concrete walls, office buildings and homes is a treasure trove of food.

[♪♪♪] Gardens.

London has over three million of them.

They make up a quarter of the city.

[bird chirps] Many bursting with flowers, full of sugar-rich nectar, just what the bumblebees need.

And all the workers have to do now... is find them.

[♪♪♪] [trumpet fanfare] Bumblebees can travel as far as seven miles a day looking for food.

That's the equivalent of a human circumnavigating the globe ten times... [♪♪♪] just to get to the store.

If they don't manage to feed every 40 minutes, they risk starvation.

The key to the bumblebees' success lies in their ability to navigate the urban world.

Like London's legendary cab drivers, they use landmarks to build up a mental map of the city.

[♪♪♪] And using the sun to orient themselves, they can easily find their way to the best flower spots and the most direct routes to and from them.

[buzzing] The industrious army works day in and day out.

And with each worker bee able to carry their own body weight in nectar and pollen back to the nest... [♪♪♪] the colony gets stronger and stronger.

[♪♪♪] In just three months the queen and her tireless workers have harvested everything they need from London's gardens.

[birds chirping] With the bountiful food available and their extraordinary ability to find their way around, bumblebees, who have lost much of their wild habitat, are now thriving in urban areas.

Navigation lies at the heart of every successful commute and there is one animal, above all others, who truly has it mastered... even in one of the most complex cities in the world.

[distant chanting] In Morocco, Fez, an epicenter of trade, is a maze of nearly identical alleys - that GPS cannot penetrate.

For many travelers it is very easy to get lost here.

But there's one animal who can navigate this labyrinth with ease.

Pigeons.

One of the best urban navigators in the animal kingdom.

[♪♪♪] Their brains can process visual information three times faster than that of a human.

These highly intelligent birds can also orient themselves using their sense of smell.

[sizzling] detecting slight chemical changes in the wind from hundreds of miles away.

[♪♪♪] And with an internal navigation system tuned to the earth's magnetic field... they're able to fly thousands of miles with pin point accuracy.

These navigational super powers enable this group of pigeons here in Fez to pick out one very specific rooftop as a place to rest their wings and feed.

It's a house owned by Adil Bendali, a lover of pigeons since he was a young boy.

[Adil speaking in Arabic] NARRATOR: Adil looks after the pigeons that land on his roof seven days a week, 52 weeks a year.

He hasn't taken a vacation in 12 years.

[♪♪♪] But this is not a one-sided relationship.

This is Fez after all, a city built on trade.

the pigeons must pay their way and Adil has very specific deal in mind.

[speaking in Arabic] [♪♪♪] He knows that there is something that pigeons produce here in Fez that is deemed a precious commodity.

Droppings.

A key ingredient in Fez's age old leather tanning industry.

The ammonia in the droppings softens the leather and gives the tannery a unique smell.

[♪♪♪] This technique has been used here for over a thousand years.

[♪♪♪] The supple leather it produces is the reason that merchants persist in finding their way through Fez's maze of streets.

And also the reason why its inhabitants have developed such a strong bond with these urban navigators.

[pigeon cooing] But not all inner-city commuters can boast such a symbiotic relationship with humans.

Some that are feared rather than loved have been forced underground.

With over five million people trying to get to work every day, rush hour in Thailand's capital is notoriously bad.

People here spend on average a month of every year commuting.

[♪♪♪] [doors hiss] And as the daily grind in Bangkok continues above ground a wild commuter, shunned from society, has to make its way across the city... in the shadows.

Driven underground by its bad reputation, born from folk tales passed down from generation to generation.

[woman speaking in Thai] [♪♪♪] [♪♪♪] NARRATOR: Although attitudes have begun to change the creature maintains a low profile.

The sewers are the perfect place to hide, especially for a water monitor.

[♪♪♪] [water dripping] Only by filming under controlled conditions can we see what underground life entails.

These giant lizards have a colossal appetite and are always on the hunt for food.

[water splashing] Being banished to the sewers can have its advantages.

They're a maze of secret passageways that criss-cross the city.

And as chaos reigns above, water monitors travel these hidden highways with ease.

[water splashing] [♪♪♪] [traffic hums] [water splashing] By far the most popular destination... is here.

The city zoo.

[elephant grumbles] Not normally a place a wild animal would enter voluntarily.

But the zoo welcomes them and it is believed to have the highest density of wild water monitors in all of Thailand with over 100 regulars.

They're all here to visit one location.... at a very specific time: lunch time.

[dishes clanging] [♪♪♪] Water monitors can grow over six and a half feet long, and weigh more than 110 pounds.

And the bigger the lizard the bigger the appetite.

After a long journey hunger gets the better of these giant reptiles.

Frustrations begin to boil over.

[♪♪♪] [sizzling] Meanwhile, inside the zoo restaurant, friends Gaan Malasi and Dew Perdsi help out in the kitchen.

[♪♪♪] Their main chore is taking out the trash.

They've got an ingenious solution to recycle their food waste.

Water monitors are scavengers and will eat almost anything.

For Gaan & Dew it makes working in the restaurant much more enjoyable.

[speaking in Thai] Normally water monitors are shy and secretive.

An encounter like this is unusual.

They have learned that the reptiles are nothing to fear.

And the water monitors have found their piece of paradise in Bangkok, a place where they are welcomed.

And that lets them return to the sewers with full stomachs.

[water splashing] While most wild commuters travel into our cities, some do the opposite.

From the city to the wild.

And for them the stakes couldn't be higher.

Here in the foothills of the Canadian Rockies, it is the dead of winter.

[train rattles] At this time of year Calgary is a refuge to over 30,000 mallards, seeking shelter from the bitter cold.

[ducks squawking] The warmth generated by people and industry has kept the local waterways open and the ducks warm.

But what they don't have here is enough food.

[♪♪♪] Each day the ducks head out of town to find something to eat.

[♪♪♪] [duck squawks] In the surrounding countryside temperatures plummet to minus 22 degrees.

[ducks squawking] Flying here burns twelve times more energy than resting, draining their reserves.

And the nourishment they so desperately need is hidden beneath the snow.

[ducks squawking] Lifesaving spilt grain.

[ducks squawking] The hungry ducks waste no time.

They are being watched.

[squawking continues] It's a risk they take every day on their commute but they have no choice.

If they stayed in Calgary, they'd starve to death.

[♪♪♪] The ducks are safe if they stay together and hold the line but exhausted from the journey some can't keep their eyes open.

[♪♪♪] It has not gone unnoticed.

A prairie falcon won't turn down an opportunity like this.

[♪♪♪] [ducks squawking] Spooked by the attack the ducks make a break for home.

[ducks squawking] But this is what most predators have been waiting for.

Weighed down full of food, the ducks are much slower.

Gyrfalcons and bald eagles begin their aerial attack.

Escaping from the talons of one can lead you straight into the claws of another.

[ducks squawking] Going it alone is a gamble, but no duck will be safe until it reaches the shelter of Calgary.

[♪♪♪] Six times the duck's size and able to fly at 100 miles an hour the bald eagle is a formidable hunter.

[♪♪♪] [♪♪♪] It's a miraculous escape.

[ducks squawking] The large majority of the flock make it back to the safety of the city.

though tomorrow they'll have to run the gauntlet all over again.

[duck quacks] Across the world city residents have welcomed wild commuters.

[ducks squawking] And many, like the ducks, have become familiar friends.

But as the urban world grows we are coming into contact with more unexpected animals.

And making unlikely alliances.

[car passes] Here in St. Lucia, South Africa, an agreement has been made with the most surprising animal of all.

[lights hum] One of the biggest and most dangerous on the continent.

After dark when the streets begin to empty... the beasts arrive.

[grumbling] [radio chirps] The night time commuters... are hippos.

With limited street lighting the best way to see what they are up to... is with a thermal camera.

Each night they travel in from the nearby river.

They are all after just one thing: grass.

A hippo can eat up to 90 pounds in a single sitting.

They can only pull it out with their lips, so they prefer short grass, which is easier for them to eat.

The roadside medians and manicured lawns of the residents' gardens offer the perfect buffet, especially for the young and old, who can't travel far.

[dog barks, whimpers] So whole families commute into the town to eat dinner.

Which means each night St. Lucia's residents share their front lawns with multiple one-ton animals.

[♪♪♪] You'd think that having an animal this deadly, this close, would be hard to tolerate.

But miraculously there has been little conflict.

Rather than force the hippos to change their behavior, the residents have changed theirs.

The people of St. Lucia have learned to give the hippos the respect and space they need during their nighttime feedings.

[♪♪♪] Come morning the benefits can be seen.

The residents have freshly mown lawns, and the hippos, back in their wild river home, have full stomachs.

[hippos grumbling] If the most dangerous and surprising of all wild commuters can succeed in getting just what they need from the city while still keeping one foot in the wild then as the urban world grows there is hope that more can follow.

And with far reaching benefits, it may just be the start of a new and very modern migration.

[♪♪♪] [penguins squawking] [bear grunts] [car passes] [♪♪♪] ANNOUNCER: To order Wild Metropolis on DVD visit ShopPBS.org or call 1-800-PLAY-PBS.

This program is also available on Amazon Prime video [♪♪♪]