All language subtitles for Animal Empires - 01x05 - Migration Eng

* MUSIC

NARRATOR: Twice
each year,

in Canada's
frigid north,

millions of caribou

embark on
an epic journey,

the largest
mass migration

of any mammal
walking the earth.

On the California
coastline,

massive elephant seals
meet to breed

and battle
after months at sea.

Monarch butterflies flutter
thousands of miles

in a multi-generational
marathon.

These creatures survive
incredible migrations,

overcoming
deadly obstacles,

crossing oceans and
continents,

to ensure the future
of the species.

Inside the different realms
of the wild kingdom,

members of
a single species

assemble in droves,

one flock,

herd,

or troop

reigns supreme.

These are
the world's great...

NARRATOR: Nunavik,

the most
northern reaches

of the Canadian province
of Quebec.

This is the tundra,

a wild, empty
expanse of land.

But it won't be empty
for long.

It's late August;
a restless time here.

This caribou
is heading south.

Sometimes called reindeer
in other parts of the world,

caribou got their name from
a Mi'kmaq First Nation's word

meaning one who
paws at the ground.

They scrape the ground
with their hooves

to dig up lichens

that comprise the bulk
of the caribou's diet.

He stands five and a half
feet tall at the shoulder,

the third largest member
of the deer family.

He spent
the past five months

in the farthest northern
reaches of his range.

But as the days
grow shorter,

it's time to move on,

to sparse forests
called taiga,

hundreds of miles
south,

where he will
spend the winter.

And he's not alone.

This is
the Leaf River herd.

It's an animal empire
on the move,

the largest caribou herd
in North America,

estimated at
330,000 animals.

The herd marches in
long strands

stretching for miles

on wide expanses
of open land,

coming together at
narrow passes and obstacles.

And The Leaf River herd
is only one of many.

Millions of caribou migrating
to cross the tundra

each spring and autumn.

The greatest land migration
on earth.

Caribou are an important
cultural and dietary keystone

to the people
of the North.

One Inuit story says
the first woman on earth

dug a hole in the ice
to fish.

From the hole, she pulled
every animal in the world,

the last to come
was the caribou.

She ordered the caribou
to multiply.

Soon they covered
the land.

Enough caribou
to feed all of mankind.

Unlike other deer,

both male and female caribou
can grow antlers.

But only some does
grow them,

and they're
proportionately small,

compared
to most deer.

The males
are much larger,

for jousting with
other bucks.

Only the moose can boast
a more impressive rack.

Three months ago
in spring,

the Leaf River herd
moved north.

The females led
the migration,

searching for
the perfect place

to have their babies

far away from forest predators
like wolves.

Now as winter
closes in,

food in the North
is becoming scarce.

They've got to move.

They'll be bringing
a new generation with them.

There's not much time
to grow up.

At just two weeks old,
these fawns must struggle

through their first
southern migration.

With junior in tow,

the return will be
far more dangerous,

and slow going.

The treeline is
hundreds of miles away.

The survival of
the empire

depends on
the females' ability

to get their young back
to the forest alive

before winter.

Each day presents
mortal danger.

Death could come
in the form of broken leg,

or a prowling bear.

Or it could be something
even bigger,

like a river.

NARRATOR: On the coastline
of Southern California,

these rocky beaches are
where a giant of the sea

returns after
a migration of its own.

Elephant seals are named for
the fleshy proboscis

on the massive
mature males.

They're colossally
large,

with a big bull weighing
up to 5,000 pounds,

about as much
as an SUV.

The females are much
smaller than their mates

weighing up to
1,300 pounds.

That's still more than
a dairy cow.

Twice a year,
northern elephant seals

migrate out to sea,

then return to the beaches
where they were born.

They travel further
than any other seal,

more than 2,000 miles.

The reason for
their long journey is food.

Males and females have
different dietary requirements,

so they go
to different places.

The males stick closer
to the coast,

and head north to feeding
grounds off Washington State,

British Columbia
and Alaska.

They prefer to dine
on small sharks and rays

in shallower waters.

The females go further
into the open ocean.

They've been spotted
as far west

as the Hawaiian Islands.

They prefer to feast on
open water species,

especially squid.

While at sea, the Northern
elephant seals

forage for food
almost constantly,

they may not even
stop for sleep.

They spend most of
their time underwater.

Elephant seals
dive deeper

than any other
species of seal,

and can
hold their breath

for up to an hour
and a half at a time.

But if there are to be
baby elephant seals,

male and female
must meet somewhere,

and this
is the place.

Point Piedra Blancas,
near San Simeon California.

It's September.

Elephant seals are
beginning to congregate

on beaches and rocky
outcroppings like this

all along the coastline
of California and Mexico.

It's called
"the fall haul-out".

The seals arrive
at different times

depending on
their age and sex.

Last year's pups, juveniles
and sub-adult seals

are returning to
the rookeries of their birth.

These males
are five years old,

just hitting puberty.

Their noses haven't grown to
their full fleshy length yet.

They won't grow to full
size and maturity

until they're eight or
nine years old.

The females reach
sexual maturity earlier,

at three or
four years old.

These younger
elephant seals are here

to rest and relax.

While on land
they don't eat much,

learning to fast
is part of growing up

for an elephant seal.

Adults don't eat at all
during breeding season.

But it's not all
fun in the sun.

The young males
play-fight;

sparring practice
for when they're older.

When they grow up,
these battles

will determine
who gets to breed.

They rear back
their heads

and bellow through
their undersized noses.

And go chest-to-chest,
sizing each other up.

They bare
their fearsome teeth,

but it's all for show,
mostly.

The juveniles are still
more bark than bite.

But when the big bulls
arrive in a few months,

that's when the fighting
will get serious.

NARRATOR: On the other side
of the continent,

millions of winged creatures
are about to embark

on another
huge migration.

It is one of the world's
most spectacular

mass movements;

undertaken
by one of its tiniest

and most delicate
creatures.

The monarch butterfly,

instantly recognizable,

a regal symbol of beauty
and transformation.

Its migration is
an intergenerational odyssey.

Each autumn,
monarch butterflies migrate

from their summer homes
in southern Canada

and the northern
United States

to spend winter
in warmer climates.

As summer comes in Nova Scotia's
Annapolis Valley

on Canada's
east coast,

a female is looking for
the right spot to settle down.

She's looking for
just the right plant,

the milkweed.

She's ready
to lay her eggs,

up to a thousand
of them.

As a caterpillar, the monarch
doesn't stray far

from the plant
where it was laid.

The caterpillar
is voracious,

eating its own bodyweight
in milkweed leaves every day.

The milkweed gives
the caterpillar a toxic taste

that stays with it
for life,

and keeps
predators away.

The caterpillar feasts for
about three weeks,

growing so fast
it sheds its skin four times.

Now, the caterpillar seeks out
a horizontal branch

to begin its final
transformation.

It spits out silk
from its lower lip,

creating a mat
on the branch.

Then two of its back legs
forge together

creating
one appendage.

Tiny hooks latch onto
the silk mat like Velcro.

Once its skin begins to peel,
it's only a couple of minutes

before it sheds its fifth
and final layer

of caterpillar skin.

The pale shell is
a hard exoskeleton

called a chrysalis.

The very cells comprising
the caterpillar's body

break down
into a stewy goo

and then re-form.

A week or so later,

the transformation
is complete

and the butterfly inside,
is ready to emerge.

Free from
its chrysalis,

the butterfly
hangs for hours,

until its wings
fill with blood,

dry,
and stiffen.

If this butterfly
were born in summer

it would live
six more weeks,

during which time
it would breed,

lay its eggs,
then die.

But this is
an autumn butterfly,

so after all this,

it still has a migration of
thousands of miles ahead.

NARRATOR: In
northern Quebec,

the Leaf River
caribou herd's migration

meanders through
the village of Kangirsuk.

The herd's route
changes every year,

but the migration
dates back millennia,

before there were
any towns here at all.

It wasn't long ago
that people here

lived out
on the land,

following and hunting
the herd.

Towns were built
in the mid-20th century,

and the nomadic
way of life

came to an end
for most.

But the north is changing
once again.

Caribou herds are
shrinking everywhere.

The Leaf River herd
is the largest left

in North America.

Even their numbers
are down

more than a third
in recent years.

The nearby
George River herd

used to number
nearly a million.

But in just
two decades,

the population
collapsed by 98%.

From 800,000
caribou

to just 15,000
today.

Nobody is sure why the herds
are shrinking.

The likely cause
is a combination of

commercial hunting,
industrial development,

disease and
deforestation.

In response, the Inuit have
suspended their hunt

in the past few years.

It's the first time
anyone can remember

that the Inuit haven't hunted
the George River caribou.

Caribou are uniquely
specialized

to survive
here in the north.

The short, hollow hairs
of their outer coat

provide insulation
against the cold.

Their entire body,
even their muzzle,

is fully furred.

Their long legs and
huge stride

cover massive
expanses of ground.

Even as babies,
caribou are born to run.

At just one day old,
a caribou fawn

can outrun
an Olympic sprinter.

These fawns are
just two weeks old,

and well into their first
migration south.

Mother and baby
form a bond from birth,

and recognize
each other

by sight, sound
and smell.

The fawns stay
by their mother's side

as much as possible
through the journey.

The route isn't easy.

The ancient paths
lead to a place

where the open tundra
tumbles down

a massive rock face.

The yawning valley of
the Payne River

divides
the landscape.

In open plains, the herd
splits into smaller groups,

sticking mostly with
members of their own gender,

in gatherings of a few dozen
to a few hundred.

But here, there's just
one safe path

from the highest
elevation

down to
the riverbank.

This is a bottleneck
in the migration.

One by one, the herd
trickles down the hillside

like a mountain stream.

A river
blocks their path.

Rivers can be more dangerous
than any predator.

Hundreds
of caribou die

attempting these crossings
every year.

It will take three full days
for the entire herd

to cross this river.

Instincts
and their stomachs

drive them on.

NARRATOR: It's December.

The big bull
elephant seals

begin arriving
on the beaches

of California
and Mexico.

They've been at sea
for at least three months,

bulking up
for mating season.

It's a lot of work to haul
their 5,000 pound bodies

out of the surf.

Blubber accounts for up to
50% of the male's body weight.

It keeps them warm
in the frigid ocean

and fuels them during
the hungry months on shore.

All that fat was almost
the species' undoing.

When the California gold rush
hit in 1849

there was a sudden
spike in demand

for industrial lubrication
for mining machinery.

Back then,
that meant whale oil,

but whale populations had
already been decimated.

Hunters turned their sights
to the elephant seal,

and all but wiped
out the species

in just 15 years.

In 1884, a tiny colony of
seals was discovered

off the coast
of Mexico.

It's believed
all 100,000

northern elephant seals
alive today

can be traced
to that one group.

They come by their distinctive
nose naturally.

But their pink
chest callouses?

They earn those
the hard way,

through years of battling
with other males.

Bull elephant seals
are fiercely territorial.

This one is patrolling the water
snorting and blowing bubbles

to warn off any other males
that approach.

Their noses also make
great echo chambers,

booming out signals
to other seals.

When mating season
begins,

they constantly harass
any females on the beach

until a pecking order
is determined.

The moment a juvenile male
starts getting too friendly,

a bigger bull
comes in.

The fight breaks out.

Another male
comes up the middle

to take his chance
with the female.

As though
that's not enough,

a fourth male
decides to get involved.

The female slips away
into the sea,

as the males fight it out
on the beach.

It's rare, but these battles
can be to the death.

Only one male
can conquer a beach,

or a section
of beach,

and mate with
a harem of females.

Competition must be
chased off

or beaten
into submission.

There can only be
one king of this empire,

the dominant male of
the harem of this beach.

To the victor
go the spoils.

A single male can hold
a harem of up to 50 females.

It's evolution's way
of ensuring

that only the biggest,
strongest males

pass on their genes
to the next generation.

NARRATOR: As August
turns to September,

the monarch butterfly
from Nova Scotia

begins
its long trip south.

At first, it is
a solitary voyage.

Individual butterflies
gradually

fluttering their way
southwest.

But eventually, it joins
150 million others,

the great-great-
grandchildren

of those that flew north
the preceding spring.

Remarkably, they make
the incredible journey

in a state something like
hibernation in other animals.

It's called diapause,

a slowing down
of the metabolism.

It allows a single monarch
to live long enough

to make
the entire trip south.

The migration path
follows a corridor

determined by flowering
nectar plants,

air currents and
climactic conditions.

Research suggests
the butterflies use

an internal compass
to navigate,

an operation involving
both their eyes

and antennae.

Their eyes watch the sun's
position in the sky,

which changes
throughout the day.

Their antennae contain
an internal biological clock

to determine
the time.

The butterflies'
tiny brains

compare those two pieces
of information

to determine which
direction is southwest.

They can be
blown off course easily,

but gradually re-orient
themselves.

Monarchs fly at speeds of
15 to 25 miles per hour,

overnighting together
in clusters called roosts.

Landforms like mountains
and coastlines

gradually funnel the scattered
individual butterflies together

as they get closer
to their winter homes.

The destination
for some butterflies

is California's
coastline.

Our butterfly
from Nova Scotia

will flutter
further south,

to the Oyamel fir forests
of Mexico.

The arrival
of the monarchs

in Mexico's
interior highlands

coincides with
an annual celebration,

D�a de Muertos,
the Day of the Dead.

Traditional folklore says
the monarchs represent

the souls
of the deceased

returning to the earth
for the celebration.

By December,
monarchs cover the trees.

It's not the riot of color
you might expect,

because only the monarch's
dull outer wings are exposed.

A monarch butterfly weighs
about a 13th of an ounce.

but they are so
crowded,

tree branches can creak
and break

under the weight of tens of
thousands of butterflies.

The largest monarch
overwintering sites

are in Mexico
and California,

but smaller ones
have been discovered

in Arizona and
Florida.

Until 40 years ago,
many of these places

were a secret
to everyone

except
the butterflies.

Now a few of the biggest
ones in Mexico

are protected as
world heritage sites.

Nobody's quite sure how
the butterflies

chose these places,

but it seems to be a combination
of the right trees,

climate, water supply,
forest canopy

and isolation.

The migratory butterflies
live to be six months old,

longer than any other
generation of monarch.

That's because
they put off breeding,

remaining in a state of
perpetual adolescence.

The butterflies
cluster together

to conserve heat.

They stay in a state
called quiescence,

keeping still,
and conserving energy.

Everything has to be
just right

for the monarchs
to survive.

If it's too cold,

they will burn through
their fat supplies and die.

Unusually warm weather can
stimulate them to breed,

and begin their northern
migration too early,

flying straight into
the frosty northern winter.

About half
of all monarchs

that arrive in
the wintering grounds

die before
the return trip.

Cold snaps and storms
can kill millions more.

In 2002, a snowstorm
in Mexico

killed 500 million
monarchs,

three times
as many butterflies

than the entire migration
consists of today.

Overall, the number of
migrating monarchs

is down by 75%
in the last 25 years.

But if everything
goes just right,

these monarchs
will stay here until March

and then begin their part
of the journey home.

NARRATOR: Crossing rivers
is a fact of life and death

for the caribou herds
of Northern Quebec.

Their winter home
in the forest

lays hundreds of miles
past the opposite shore.

The adaptations that
enable caribou to survive

the frozen
northern winter

also help them
in the water.

Adult caribou
are strong swimmers,

their broad hooves and
powerful legs

help them paddle
through the water.

Short hollow bristles
of their outer fur

keep them warm and
increase their buoyancy.

The arteries and veins
in a caribou's legs

are intertwined, so hot blood
leaving the heart

warms the cold blood
traveling toward it.

Their stout bodies
and short ears

minimize
their surface area

and exposure
to the cold.

Still, strong currents
can sweep

even an adult bull
off-course.

And caribou of all ages
must make the swim.

At only two weeks old,
this year's fawns

haven't had much
practice swimming.

If they get separated
from their mothers,

no other female
will adopt them.

Sticking together
is a matter of survival.

A fawn separated from
its mother,

calls out to her.

(GRUNTING)

(GRUNTING)

Mother turns back
for her baby.

She positions herself
downstream

to keep the current
from taking her fawn again.

They've made it across,

but there will be
more rivers

and other
dangers to come.

Once they clamber
onto shore,

they take
a moment to rest

and feed for
the journey ahead,

still hundreds of
miles to go.

The caribou's future
is uncertain,

both for
this year's fawns

and the entire
Leaf River herd.

Their forest destination
will offer food and shelter

for the coming
winter,

but there will be
prowling predators too,

like bears and wolves.

At just
two weeks old,

this fawn is still
only halfway through

his first
rite of passage.

He could live
another 15 years,

making 30 more
migrations.

The trip seems to be
getting longer every year.

Over the past
few decades,

the Leaf River herd's
spring calving grounds

have gradually shifted
180 miles to the north.

Researchers believe
we may be in the twilight

of this great
migration.

They fear
the Leaf River herd

will be extinct
in just 65 years.

For now, even after
clearing the river,

the herd still has
a long way to go.

The treeline is still
hundreds of miles away.

NARRATOR: It's late
December on the bluffs

and beaches
of California.

The male
elephant seals

have been battling
onshore for two weeks,

and now all the female
northern elephant seals

have arrived.

The females bicker and
bellow at one another

as they jostle
for space on the beach,

but don't fight
like the males do.

Females are pregnant
when they arrive,

and give birth
shortly after.

They lose 30%
of their body weight

during their time
on shore,

burning massive amounts
of calories nursing

and protecting
their pups.

Newborns weigh about
75 pounds.

The pups don't have any blubber,
so their black coat

helps them soak up heat
from the sun to stay warm.

Life on the bluffs is
dangerous for the babies.

They're not alone.

Coyotes prowl,
looking to pick off

weak or
unattended pups.

Even the adult seals present
a significant danger.

As males battle for
control of the beach,

a pup that can't get
out of the way fast enough

can be crushed.

Elephant seal mothers
are fiercely protective

of their newborns.

A young male
who comes too close

gets a stern
warning.

She's not as big
as the male,

but she will fight him
if she has to.

The male
won't take the hint.

Junior can't swim yet,
so he can't flee.

He's trapped between
the huge blubbery bodies.

The harem's dominant male
comes to the rescue.

He sends
the upstart male packing,

then drifts off
back to sleep.

All elephant seals
cover themselves

with sand
while on shore.

It's likely an effort to
keep cool in the hot sun.

They don't have any blubber
in their armpits,

so raising one fin
like this

is another way of
cooling off.

They scratch constantly.

It probably
just feels good,

but in a few months

it will help with
the annual molt

in which
the elephant seal

sheds huge swathes
of skin.

After giving birth, there's just
a short window of time

for the mothers
to recover

before the mating season
begins.

She nurses
for just 28 days,

then immediately
goes into heat,

signaling males
of all ages

to try to
mate with her.

The dominant male,

having fought off
the competition,

begins the courtship

by placing a flipper
across her back.

He uses his massive body
to hold her in place.

Through a process called
delayed implantation,

the pregnancy doesn't
take hold for a few months,

so birth coincides with
the haul-out next winter.

Not long after mating,

the mothers
will leave the beach

to begin their long migration
into the open Pacific

in February and
March.

The pups are left behind
for another six weeks or so.

They've got to fend
for themselves,

and survive off
the fat they've built up

until they learn to swim
and hunt on their own.

The males leave
soon after the females,

heading for the coastal
waters off Washington State,

British Columbia
and Alaska.

They'll all be back again,
first for the spring molt,

then again
in the autumn

to begin the cycle
once again.

NARRATOR: By February,
the days have grown longer

in the butterfly forests
of Mexico and California.

The changing light
draws the monarch

out of its hibernation-like
state of diapause.

It's time for the butterfly
to begin its migration north.

The butterflies
vibrate their wings

to bring their bodies
up to temperature

before beginning
flight.

They have
a long way to go.

The journey is
up to 2,500 miles,

But unlike the trip south,
the northbound journey

won't be completed
by any one butterfly,

but rather will be
an intergenerational relay.

The butterfly that came
all the way from Nova Scotia

will die soon, but first,
she will lay her eggs

on milkweed plants
along the way.

Then her children
will continue the voyage.

It takes four months,
and at least three generations

to make
the whole trip north.

Today, fewer butterflies
make the migration

than in decades past.

In northern regions,
suburban development

and herbicide use
destroy milkweed habitats

where monarchs
begin their lives.

In Mexico many forests are
threatened by logging.

In California, government
and private efforts are underway

to protect
450 overwintering sites

identified
in the state

over the past
30 years.

Butterfly lovers
hope to preserve

this flying
animal empire

for generations
to come.

NARRATOR: By land,

by air

and by sea

these creatures embark
on life-threatening odysseys

to feed,

breed

and escape
the changing seasons.

The world these animals
move through

is changing
all around them.

Some of these
remarkable migrations

are on the verge of
disappearing.

For now,
they persevere,

following paths
established

in a time before
human memory.

The world's great

moving

moving
animal empires.

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