Natural World

In Galapagos, this majestic tortoise is in a bit of discomfort.

He's got an itch he can't scratch.

The answer?

To partner up with a finch.

The finch pecks out all those irritating ticks and grubs.

The bird gets a meal,

the tortoise gets relief.

Everyone's a winner!

There are times in life

when all you need is a little help.

It could come from members of your own family,

or from some more unusual allies.

Across the natural world,

some extraordinary partnerships between animals

are being discovered.

Whether it's a lion and a lizard...

..or a raven and a wolverine...

..no matter where they are on the food chain,

many creatures have learned that life can be a bit easier

when you find a perfect partner.

Out in the wild, survival is paramount,

but even in this pristine wilderness,

just staying clean is a daily challenge.

One way is to enlist some help,

but that can depend on whether there's mutual benefit.

Across Africa, hippos are considered among the most dangerous of animals.

They can be unpredictable

and highly aggressive.

They certainly appear tough enough to look after themselves.

But their impressive hides are prone to irksome parasites.

Unable to pick up a stick and scratch their own back,

they've gone into partnership.

Meet the barbel,

a hippo's best friend.

These graceful goliaths are trailed by shoals of these loyal fish.

They even eat the droppings - what a bonus!

Once in a comfortable spot the barbels get to work,

nibbling away at all the hippo's unwanted guests.

It's a bit like a spa treatment,

complete with facial, full body exfoliation

and it seems to lull the hippos into a kind of trance.

Thanks to the food stuck to the hippos' teeth, the industrious fish

are able to feed on exotic vegetation from the land,

which would otherwise be out of their reach.

Timing and agility are essential here.

It's a peculiar pairing, but it seems to work.

The fish get a feast and the hippos submit quite happily,

perhaps making us see these aquatic curmudgeons in a different light.

Many creatures need help with their personal hygiene.

Even in the depths of the sea

are fish which could do with a bit of a once over,

but, at times, finding the right cleaner

can require a little more effort.

For these jacks,

their skin parasites are more than just annoying.

If not removed, they can reduce their growth.

This specialist cleaner fish, the wrasse, offers relief.

But the brightly coloured wrasse is recognised by many other fish,

all wanting the same service.

It leaves the jacks with a problem

as there just aren't enough cleaner wrasse go around.

So the jacks have to find a more precarious solution.

At first glance, it seems an almost suicidal option.

This is a silver tip shark and could easily eat a jack.

But these sharks have skin like sandpaper

and bumping into their flanks helps scrape off unwanted parasites.

Soon swarms of jacks pursue the sharks, all itching to have a go.

A dangerous game, but perhaps one that's tolerated.

Could all this bumping around also help to exfoliate shark's skin?

A case of you scratch my back and I'll scratch yours.

Eventually, though, the sharks have had enough

of being used as mobile loofahs and they're off.

For the jacks, they must be doubly relieved -

to be rid of their itches and to be alive.

On the African savanna, another animal is about to take a big risk.

He's very hungry and he knows where there is guaranteed food,

but catching it will mean getting up close and personal

to one of the fiercest predators around.

After a hearty meal of wildebeest,

the lions are doing their best to take a siesta.

But under the scorching hot sun,

they are surrounded by irritating and relentless flies.

Step up Mr Lizard,

perhaps the bravest cleaner in the world.

Lions do eat lizards, but having already had a much larger meal,

they are unlikely to need dessert.

Still, best to be cautious as lions can be notoriously short-tempered,

even if you're doing them a favour.

It takes a bit of courage and skill,

which not all the lizards possess.

Across the world, their lizard cousins

have struck up a similarly special relationship

with another type of lion.

The lava lizards of the Galapagos

rid their seal lion friends of flies,

which can be ticklish nuisance.

Here, the busy cleaners appear a lot less cautious and much more welcome.

Back on the savanna,

it seems that as long as the lizards let the sleeping lions lie,

they will be rewarded with a tasty snack.

How appreciative the lions actually are of their fly-swatting efforts,

well, who knows?

Some animal partnerships go much further than just cleaning.

When you need a bit of home help

or you're having a spot of bother with your neighbours,

it can be worth considering a lodger.

In the coral reefs is perhaps one of nature's oddest couples.

This lugubrious goby has been offered lodging from a shrimp.

The shrimp is the perfect homemaker,

always cleaning, digging extensions and carrying out home improvements.

Yet its chosen lodger seems rather lazy,

just hanging about and occasionally getting in the way.

Despite first impressions,

the goby is, in fact, crucial to this partnership

as the shrimp is almost entirely blind.

The goby, on the other hand, has excellent eyesight

and remains constantly alert.

So, when the shrimp is outside,

it continuously flicks one of its antennae over the goby

to make sure it's still there and the coast is clear.

The shrimp nips across to collect food from a little patch of algae

that it knows is close to home.

However, if the shrimp wanders too far there can be trouble.

That was an anemone it blundered into and it beats a swift retreat.

For a moment, it seems a little lost,

but the faithful goby finds it

and this devoted pair are soon reunited.

This predator spells danger for both creatures.

But the goby gives the signal

and both grateful landlord and lodger retreat safely indoors.

Happy with that - that's the rent sorted for another month!

Sharing a home can lead to living on top of each other,

but for some creatures, this can be a distinct advantage.

One such animal lives in the rainforests of Latin America.

The famously slow-moving sloth.

Thanks to its damp fur,

it is able to employ the help of a rarely celebrated organism - algae.

It helps the sloth blend in to its green surroundings,

providing it with a sort of living camouflage.

And the partnerships don't end there.

The nutritious algae attracts its own admirers -

insects like these moths, who like to eat it.

But the moths are welcome lodgers for the sloth

as they too bring their own rather surprising benefits.

Once a week, their sloth landlord sets off to the ground

at a pace a snail would consider reckless.

He does this for his weekly call of nature.

The female moths take this opportunity to jump off

and lay their eggs in the steaming dung.

Some hop back on to their furry friend,

bringing with them a lovely bit of sloth dung.

It's the perfect fertiliser for the growing algae,

helping to keep the sloth the right shade of green

and hidden from predators.

Perfect!

Some animals go to quite extreme depths in their quest

to find a secure place to lodge.

A pearl fish is looking for exactly that - a hidey hole.

This cumbersome oddball could be the answer.

A rather strange looking lump known as a sea cucumber.

It spends its days sucking sand in through one end of its body,

extracting anything nutritious from it

and passing what it doesn't want out the other end.

It is the ultimate beachcomber.

OK, it's revolting, but could this walking colon be a safe haven?

It seems it could and, strangely,

it prefers the 'back door' to the front.

Any port in a storm...!

But the pearl fish is, in fact, very clever.

Sea cucumbers are repulsive to most predators,

meaning the crafty lodger is safe inside.

In fact, it is such a comfortable pad that, after settling in,

it is happy to share its home with friends and family.

Now, time for a breath of fresh air!

Whether invited or not,

partnerships can involve all kinds of diverse creatures.

Some of these creatures pair up not with animals, but with plants.

In Madagascar, the baobab tree is regularly pollinated

by the giant hawk moth.

But the tree also plays host to another creature,

one which will kill a moth.

The mouse lemur,

one of the world's smallest primates.

He drinks the sweet nectar from the tree's flowers.

It's packed with sugary energy.

But he particularly enjoys a meal of moth.

It seems the lemur is doing the baobab no favours

by killing its moth pollinator but, without knowing it,

this mini assassin is actually performing the same role.

As he wrestles with the moth, his fur becomes dusted with pollen.

Later, as he moves from tree to tree,

this will spread across the forest, helping other baobabs to grow.

So, in this relationship, the baobab is surprisingly the ultimate winner.

On the other side of the world

is a partnership which has knock-on benefits

for the most unlikely of candidates.

This Sundarbans in southern Asia

are the largest tidal mangrove forests in the world.

And a tiger reserve.

Mangroves are the only trees that can exist in salty water.