Life Story

So far on Life Story,

we have seen animals face the dangers of childhood.

Watched them enter the adult world.

Now, young animals need to find a home.

Somewhere they can find the necessities of life.

It can be a refuge from enemies.

And a shelter from the elements.

Without a place of its own,

an animal will struggle to survive.

On the vast plains of Zambia,

this isolated thicket is a rare patch of cover.

It's home to a pack of hunting dogs.

The arrival of a dozen tiny pups

means the pack have, for now, given up their nomadic lifestyle.

Here, they can hide the youngsters out of sight of their many enemies.

It's the dry season and food is scarce.

Whenever the pack leaves on a hunting trip,

one dog stays behind as baby-sitter.

If danger threatens, the pack's future will depend on this dog.

An eight-foot-long rock python is hunting.

It can easily grab a pup, if it can launch a surprise attack.

DOG BARKS

The adult has spotted it.

His attempts to drive it away have the worst possible outcome.

It retreats down the pup's burrow.

Now, the adult faces a critical choice.

Stay put and risk living with a predator,

or try to find a new shelter in the few hours before nightfall.

That would mean leading the pups into the open.

The baby-sitter makes his choice.

Unfortunately, these plains are home to hyena.

They are the hunting dogs' greatest enemy.

A hyena will take a straggling pup if it gets the chance.

It might win a battle over a pup with a lone baby-sitter.

But the rest of the dog pack, returning from the hunt,

is a different matter.

The hyena will avoid this confrontation.

Back at full strength, the dog pack can now lead the pups

to the safety of a new refuge.

Secure again,

the pups squabble over the meat carried back by the hunting party.

Its duties over, the baby-sitter can take a well-earned rest.

And, in a few weeks, the pups will be old enough to leave the den

and join the pack on the open plains.

In nature, good homes are all too rare.

Here, on a tiny Caribbean island

off the coast of Belize,

there is a severe housing shortage.

Hermit crabs use abandoned seashells as mobile homes.

As a crab grows, its shell becomes an ever tighter fit,

so eventually a crab needs to move in to a bigger one.

Suitable empty shells are few and far between,

and this one is far too spacious for this crab.

But, instead of continuing its search,

this small crab settles down to wait.

Other crabs, also looking to upgrade to a bigger home,

soon gather whenever a shell washes ashore.

Unfortunately, the new shell is too big for them, too.

Despite that, the gathering crabs

begin to measure each other up,

and then they do something really rather extraordinary.

They arrange themselves into an orderly queue.

The biggest at the front, smallest at the back.

They're lining up with one aim -

to exchange properties.

But none of the crabs

can make a move,

because the chain is not yet complete.

They're all waiting for the right sized crab to come along.

And this is it.

The latest arrival pushes to the head of the queue.

At first, the chain falls apart.

As it reforms, the small crab finally makes its move

and takes its place at the end of the line.

After a close inspection,

the big crab moves in.

This triggers a chain-reaction.

Each crab hurriedly moves into the shell

vacated by the crab ahead of it in the line.

Just as the small crab attempts to move into its new home,

a fresh arrival muscles in.

To be left without a shell is a death sentence.

A naked crab will quickly cook under the intense tropical sun.

But, after all the swapping,

there is still one shell left.

Sadly, it's no bigger than this

small crab's original shell,

and worse, it's got a hole in it!

But even a bad shell is better than being homeless.

The small crab's need to upgrade

will be even more urgent

by the time the next shell rolls ashore.

This old wreck off the coast of Fiji

is a gathering place for some very unusual fish.

They're called remoras, but this isn't their home,

it's more of a waiting room.

Like hermit crabs,

each remora is waiting for the perfect residence to appear.

The unique suckers on the back of their heads

hint at a very different and unusual lifestyle.

Up above is a coral reef.

The remoras watch and wait for a particular visitor.

Sharks.

Most fish make themselves scarce when they appear.

But not remoras.

For a remora, home is a bigger fish.

And this is an opportunity not to be missed.

A passing school of eight-foot bull sharks,

one of the most aggressive marine predators.

Remoras stick very close, or even clamp onto their host

with their suckers.

And what fish could offer better protection than a shark?

What's more, when the shark makes a kill,

the remora can scavenge the leftovers.

In return, it helps the shark by eating parasites from its body.

But too many remora could slow a shark down,

so they try to avoid becoming over-loaded.

That means intense competition among remora for the available spaces.

This one has missed out.

Fortunately, sharks aren't the only suitable visitors to this reef.

A giant Manta Ray offers a remora another chance.

It's already sheltering several large remoras.

But there's room for one more on this huge fish.

At last, the remora has a safe home.

But, having made its choice, the remora must now go

wherever the Manta takes it,

for better or worse.

Some animals build their own homes,

and if their lives are filled with danger,

then that home needs to be a fortress.

An Australian weaver ant carries part of her colony's future,

a grub, in her jaws.

She's on her way to help in the construction of her new home.

Hundreds of her fellow workers are labouring together

to build a stronghold out of leaves.

Chains of workers pull leaves together.

They hold them tight, but they need a more permanent fix than this.

The grub-carrier will play a crucial role.

But first, she needs to get across the construction site.

Workers use their own bodies to make living bridges between branches,

allowing others to move quickly around the site.

This worker, with her grub, crosses over.

When this worker reaches a leaf that needs securing,

she taps the grub on its head.

This stimulates it to produce silk.

The worker uses the grub like a glue gun,

passing it backwards and forwards across the join.

Silk is one of the strongest fibres in nature,

yet, it's also flexible, making it the perfect glue

for a construction that must bend and flex in the wind.

After just a few hours of intense effort, the ants' home is complete.

Totally weather-proof, this new nest makes the ideal nursery

in which to start rearing a precious brood.

RAIN PATTERS

But it also needs to be a fortress

because neighbouring ant colonies,

looking to expand their own empires, are always on the attack.

WIND HOWLS

It's rare that a home provides an animal

with everything it needs to survive.

Some are a dangerous compromise.

A sheer rock face in the American Rockies

provides a sure-footed mountain goat with security from attack.

The goats spend the entire winter up here.

But although safe from predators, there's little food.

By the time the spring moult arrives,

their poor diet has left them suffering

from a serious deficiency of vital minerals.

So, every spring, the goats must leave the safety of the cliffs

and make a dangerous, three-day-long descent

on a quest for these precious salts.

While mothers guide the new-born

kids down to the valley,

this newly independent young goat

is making the perilous journey alone for the first time.

The sun's warmth has brought predators out of hibernation.

A grizzly bear.

It's a deadly threat to a young goat.

Luckily, the remains of an earlier casualty catch its attention.

The yearling has to make his way without guidance.

High up, avalanches and rock falls are a hazard.

Lower down, rivers swollen with meltwater

pose the greatest danger.

From experience, mother goats know the safer places to cross.

For her new kid, it is a daunting prospect.

It could easily be swept to its death.

After several days, the lone yearling approaches the crossing.

On the other bank is the only place for miles around

where rocks rich in salt are exposed.

All that stands between the young goat and the outcrop

is a last cascade of bitterly cold water.

It's hard to know where to cross without help.

He's made it.

He'll stay a few days,

stocking up on the salts in this rich dust,

before facing the dangerous return journey

back to the safety of the peaks.

In Zambia, the hunting dog pups

are now four months old

and have left the security of their den far behind.