Original subtitles

In the baking heat of the African savannah...

..as rivers dry up...

..animals flock to the waterhole.

But we've never fully understood

how a single water source can support so many competing species.

So we're doing something ground-breaking.

Welcome to Tanzania and to the Mwiba Wildlife Reserve

and to this unique waterhole behind us.

We are working with the reserve to create the world's first

waterhole with a built-in specialist camera system.

This waterhole has a half-submerged filming hide right in the middle,

and it's rigged with remote cameras so we can see

every angle of animal behaviour like never before.

GIRAFFE GRUNTS

It's a unique chance to follow the evolution of a waterhole

ecosystem and the lives of the animals that depend

on it, from the very beginning.

This is our first visit from a lion.

We don't know who will turn up and in what number...

..but we want to observe and record every single species...

..over a period of six months.

We're filming from the start of the life-sapping dry season

when water is scarce and tempers fray.

That's not a happy elephant.

Until the pressure finally breaks...

THUNDER CRACKS

..and the annual rains change everything.

From up here, you get a great view of an ecosystem.

We'll follow the fight for survival at the one place all animals gather.

Everything changed when the predators turned up.

This is the story of life...

ELEPHANT TRUMPETS

..and death at the waterhole.

In East Africa, Tanzania,

south of the Serengeti ecosystem

is a protected area spanning 53,000 hectares.

Mwiba Wildlife Reserve.

It's a safe haven for Africa's most iconic species,

including elephant...

..hippo...

..giraffe...

..leopard...

..and lion.

But in our changing world,

this region faces a growing shortage of water.

Look at it, so green, fresh, verdant.

That said, in a couple of months' time, all of this

will be parched and brown.

All of these tiny little pools of water will be gone.

And the wildlife here is going to be struggling to survive.

For half the year in 2018,

there was just nine millimetres of rain.

Well below average for Tanzania.

And with the growing impact of climate change,

life here is set to get tougher.

Temperatures in Africa are rising.

In just 30 years, it's predicted the continent will endure 50%

more warming than the rest of the planet.

As a result, many natural water sources are drying up.

Let's just call this digger in.

To give its wildlife a much-needed lifeline, Mwiba Reserve has decided

to build a waterhole on an open patch of grassland,

easily accessible from all directions.

Natural waterholes appear after rains deep in the savannah,

but they're quickly populated by wildlife and often dry up fast.

So this is a unique opportunity for us to work with Mwiba and study

a waterhole built from scratch.

Look at that!

It's very exciting, isn't it?

We want to find out how hundreds of different species find,

use and interact around a new water source.

Wow. OK. Now, I measure about...

I don't measure about anything.

I'm 1.83 metres and I'm still above this.

We ideally, I think, we want about

two metres depth at our deepest point.

But what's essential is going to be the slope like this,

because a lot of animals are not going to literally go in.

That's going to be our wallowers - our, you know, elephant,

our buffalo, our warthog.

I think many of the ungulates are going to come to the edge here,

stand on that edge and sip.

And certainly all of the bathing

animals are going to be in this zone, so the shallow part of the

waterhole is going to be equally important.

It's going to be fascinating.

I honestly think that we're going to see an enormous diversity

of species coming to this waterhole.

To uncover the secret world of the waterhole, we're bringing in

a weatherproofed remote camera system,

able to record day and night.

To help make it wildlife tamper-proof,

we dig two-metre-deep trenches...

..excavating over 100 tonnes of soil for 4km

of fibre-optic cable.

60,000 litres of water fill two separate pools,

giving more access points for thirsty animals.

This is a project on a grand scale.

It's bigger than any of the other waterholes that are currently

here at the end of the wet season - they're just puddles.

This is going to be a pool of some significance.

We are going to film here at three of the most critical times of year

for local wildlife.

From the middle of the tough dry season.

Then, a couple of months later, when temperatures soar into the 40s

at the hottest time of year.

And finally, at the height of the first rains.

Now, it's the middle of the dry season.

20 cameras are set to record

every detail of life for the next two weeks.

They are remote controlled from our base camp,

where biologist Ella Al-Shamahi

and I can watch them live and play back footage.

We've got our team monitoring these cameras 24/7.

Those strange triangular structures, those are so that the elephants

hopefully won't step on the cameras and damage them.

As Ella says, it's 24/7, we're watching them throughout the course

of the day and the night using infrared.

And, of course, we're also watching this waterhole from the air.

We've got a drone up at the moment.

And there you can see from mission control, it's about 200 metres

across this parched grassland down to our waterhole complex here.

A tunnel leads into our hides so that we can sneak in

without the animals seeing us.

And we've got the two pools either side here.

For our first two-week filming window, I will be attempting

to collate data for every visitor and create a species list

so we can track how many animals come to a new waterhole.

Chris will be reviewing footage to analyse the complex animal

behaviour behind every interaction.

Our first question - how long does it take wildlife to find

a new waterhole?

The answer - 45 minutes.

WARTHOG GRUNTS

Here, top right, we've got warthog.

Wow, that's awesome. Yeah.

It's a whole family there.

Mwiba wildlife expert Eugene Raymond joins us to review

the footage, to offer some local insight

into our waterhole pioneers.

We've seen these in and around Mwiba area,

and it's one that's got a very interesting story

cos the mama died and then

the four little ones managed to get to this level.

So you've seen them growing up? Yeah, I've seen them growing up.

These warthog orphans live 250 metres away.

They probably discovered the waterhole whilst foraging for food,

but, interestingly, they're not here to drink.

What they really need...

..is mud!

It's a stifling 35 Celsius,

but warthogs don't have sweat glands

that regulate their body temperature...

..so they must use mud to cool themselves down.

Our camera rig includes a specialist thermal camera,

which reveals how effective this behaviour is.

The warthogs' bodies turn blue as their temperature decreases.

Mud bathing can reduce their body temperature

by a life-saving 3.6 Celsius.

The warthogs weren't on their own for very long.

Look, the warthogs scarper as soon as the elephant arrives.

ELEPHANT TRUMPETS

They would normally give respect for this big beast to come in

and get some water.

What's interesting is that they have the capacity to smell water.

Ah, yes, that's very true. Absolutely.

What, 15 miles away at least, I imagine.

I believe they have incredible ability to do it even

farther than that. Further than 15 miles? Yeah, for sure.

It's not really that much of a surprise, then,

that they would be amongst the first to turn up.

So here's another one. That's another male.

Do you know this elephant?

Oh, that's a young bull that I know, for sure. Yeah.

You see the right tusk is shorter than the left tusk.

If you look at one tusk that is shorter than the other,

then you get to know...

This elephant is either right-handed or left-handed.

The guides call this elephant Nusu, which in Swahili means "half".

And his companion is Ndogo, which translates as "small"

because he has short tusks.

An African elephant needs to drink nearly a bathtub of water each day.

They may have to walk up to 195km to find enough.

We've made elephants happy by giving them fresh, clean water.

It's not often you get to make, you know, megafauna happy.

Especially in the dry season.

Elephants are thought to help

other animals locate water in the dry season.

As they forage, the two males inadvertently create pathways

through the bush leading directly to the waterhole.

This area is home to lions, leopards and giraffes.

We know they're out there, but we don't know

when and if they'll turn up to the waterhole.

And you've got to remember that up until fairly recently,

this waterhole simply wasn't here.

15 minutes after the elephants, more new species arrive.

And by reviewing the footage from day one, we discover

how different animals approach a new water source.

Ella! Ella.

Got impala that have come in.

Waterholes are dangerous places for impala, as big cats often hunt

them when they come to drink.

I mean, they are extremely nervous.

They're essentially a forest antelope,

so coming into the open like this is a perilous exercise.

Impala aren't the only species that are wary at the new waterhole.

Now we have zebras.

The first zebra also approach with caution, but there's a theory

that suggests they have some natural protection from predators.

I don't think there's a definitive answer, but do you know why the

zebra's got stripes?

I'm assuming it's some kind of a camouflage thing.

I was looking at some work relatively recently that shows

that when you get a large herd of zebra moving,

the way that their bodies move cycles the stripes

and visually is disorientating.

It forms an optical illusion, which generates an enormous amount

of confusion in terms of the visual capabilities

of any pursuing predator. Really?

It's confusion colouration.

That's interesting. Hm.

To add four species to our list on day one, within just a few hours

of the waterhole being finished,

shows just how harsh the dry season is.

50 metres away, the nearest water source in the area,

the Arugusinyai River, is completely dry.

And for herbivores, it's not just water that is in short supply.

Look at it, it's absolutely parched.

Imagine trying to eke a living, eating something like this.

I mean, there must be nutrients there,

but trying to firstly digest it and then process it...

Thankfully, there is some evergreen foliage left here.

This acacia, look at this.

Looks relatively lush and green,

but it comes with a cost - protected by these vicious spikes, of course.

Again, not all of those herbivores

are going to be able to nibble this.

And then lastly, there is something that makes this environment very,

very hostile at this time of year,

not just for all of those animals, but for us, too.

And it lurks...here.

Look at that, almost bumped into it.

You see this little brown smudge

in the crook of the grass here?

That is a solid mass of ticks.

They call them pepper ticks at this stage because they're so small,

they're about the size of a ground piece of pepper.

And any animal that brushes into this grass here is coated.

They get under the skin and they start to suck its blood.

At this time of year,

this part of Tanzania is a tough place to be wildlife.

At night there is some relief, as temperatures drop to 15 Celsius.

But this is often the most dangerous time to be at a waterhole.

Lions, leopards and hyena are more active after dark.

Our specialist camera system switches to infrared light...

..so we can watch the waterhole for nocturnal predators.

And on the first night, just before 8pm,

the cameras catch one of Mwiba Reserve's most elusive

and powerful hunters.

Leopards have the largest ranges of any big cat.

Males can range over 2,000 square kilometres.

It's not clear if this male is a Mwiba resident

or just passing through.

LEOPARD GROWLS SOFTLY

We collate all the camera footage.

THUNDER RUMBLES

Wow. Oh, look at the elegance.

And expert guide Eugene joins us

again to review the shots in order to identify him.

It's probably one of the leopard that I know in the area.

We've named him Jasiri. And what does that mean?

Jasiri is a Swahili word and it means "brave".

He's not very skittish, he's quite relaxed.

Those rosettes are unique to every leopard.

Every leopard has a unique spot pattern.

Those markings on the whiskers, up to the nose on the side,

these are the ones that will tell you which one it is.

They will never be the same.

Jasiri's arrival is a sign that our new waterhole is beginning to get

the attention of Mwiba's carnivores.

Leopards hunt a wide variety of prey, feeding on everything

from insects to rodents to large antelopes.

The waterhole could be a new important hunting ground for Jasiri.

So what do we think? Do we think he's already had a kill?

He's probably got a kill somewhere and put the kill up a tree.

Look at his neck, the muscles in the neck and that gives them

the power of getting up, carrying stuff, heavy stuff,

pretty much the same size, and they will take it up a tree.

Because they are in so many competitions with other predators

like hyenas, lions,

and they would come for a drink

and go back on their same spot at the kill.

It doesn't need water every single day.

They get it in two ways.

They get it from the body fluids that they take out of the animal.

And then they also, when they're digesting it,

they produce metabolic water.

So in the process of digesting that food, the hydrogen teams up

with the oxygen and produces water and that can provide them

with up to 10% of the water that they need.

And that's the difference between dying of thirst

and not dying of thirst.

So it's really important for these types of animal,

that metabolic water.

What a view, and what an animal.

Mwiba Reserve is home to lions and spotted hyena,

but Jasiri the leopard beats them to be the first apex predator

on our species list.

After his visit, the night is quiet at the waterhole.

But the silence doesn't last long.

BUFFALO GRUNT

At 7.30 on the second morning,

the biggest herd of animals comes for a drink.

80 Cape buffalo.

If we go to this camera over here,

can we take a closer look at them on the ground?

BUFFALO GRUNT

They're an enormously robust and powerful animal.

The males weigh up to a tonne.

Their horns grow to a metre across, fused in the middle.

They're very much front-heavy, massive fore-limbs.

Look at that, you can see the

pulsing throat of a buffalo.

Some of the species that we have here don't need to drink every day,

but buffalo like to drink every day

and they drink an enormous quantity of water.

That's the equivalent of a nice cold pint of lager

at the end of a very hot afternoon.

Look at the look of satisfaction on that buffalo's face.

Well, maybe I'm pushing the anthropomorphism there

a little bit, but I can imagine it's a happy buffalo.

The waterhole is a lifeline to water-dependent animals

like Cape buffalo.

This herd can drink up to 3,000 litres in just one visit.

And the buffalo aren't travelling alone.

Oxpeckers provide an invaluable service

to buffalo in the dry season.

And in return,

they get a free ride to water and all the food they can eat.

They're on there removing parasites,

plenty of ticks here at this time of year.

Ooh, straight...straight in!

And, look, right inside the ear,

and you can see where there's less hair in there, how it will be easier

for the ticks to attach.

Look at that, it's feeding furiously.

So we can't see them, but undoubtedly, this oxpecker can.

CHRIS LAUGHS

Can't imagine what it must be like to be the buffalo with a bird

right inside your ear.

But, clearly, it is happy

with that compromise because

this bird is feasting on

those parasites which are inside that ear.

Love that! Little cameo of natural history that we're able to see

because we've got these extraordinary cameras

and we're so close to these animals.

Over the next few days we add an incredible 40 new species

to our list.

Including four birds.

Yellow-billed storks often hunt in shallow water.

Black-faced sandgrouse come to waterholes not only to drink,

but to wet their breast feathers

to carry water back to their chicks.

Cape turtle doves are found across southern Africa.

Bare-faced go-aways.

The species get their name from their distinctive call,

which sounds like, "Go away."

GO-AWAY CALLS OUT

African hare hop in.

Water helps them digest vegetation.

On night three,

a lone waterbuck that needs water

daily to survive,

comes for a drink.

Two species of primates also find the waterhole -

olive baboons and vervet monkeys.

They like to socialise around water sources,

much to the annoyance of some of our residents.

SQUAWKING, CHATTERING

By day five, the list has grown to 20 species.

We are also seeing the same animals returning every day.

Our cameras have already recorded

nearly 200 hours of footage combined.

And I'm seeing a pattern emerge.

We're actually starting to see

some really interesting data.

We're looking at which species

are turning up to the waterhole at what time.

Some of these animals have pretty much set times

and they're turning up like clockwork.

There is already a schedule to life at the waterhole.

From around 8am, a steady stream of impala come for a drink.

11.00 is the most frequent time for zebra.

ZEBRA SNORTS

Around 1pm, the very punctual warthog orphans come to mud-bathe.

3pm is when elephants often turn up.

ELEPHANT TRUMPETS

And the herd of buffalo are coming

first thing in the morning and at dusk.

BUFFALO SNORT

I have a theory as to why this routine has been set

so early on within this new waterhole community.

There's certain patterns that indicate survival strategies.

It's interesting that during that midday sun, that real heat,

the place doesn't become deserted.

So some of the species that are most vulnerable from predators,

they're willing to brave that scorching heat

because if they turn up later in the day,

that's when the predators are about.

The fear of predators is affecting when animals come to the waterhole.

But that's not the only thing the cameras are revealing.

After eight days, a hierarchy

is developing within the waterhole community,

and by analysing footage, we discover that one species

is trying to dominate.

What we've got is a waterbuck here, and where we're seeing these come

to our waterhole, this male, they're always coming on their own.

The buffalo approach... So he was there first.

He has a look round... Oh! He darts off, doesn't he?

He doesn't even bother to entertain any thought of staying there

with a huge herd of buffalo.

They encircle the waterhole and they basically just own

that very valuable resource.

We've got another bit as well. Here we go.

So these small group of zebra have come all the way round the side

of the pool to the other end

where they're hoping to have a little sip.

But as you can see, there's another buffalo.

Just wait to see what happens.

ZEBRA SCREECH

That's deliberate aggression, isn't it?

The buffalo are completely monopolising the area. Yeah.

OK. So the big boys have pushed out the zebra,

but what happens when an even bigger boy turns up?

ELEPHANT TRUMPETS

BUFFALO SNORT

ELEPHANT TRUMPETS

That's not a happy elephant.

The buffalo are not drinking,

notice, they've had to stop drinking.

They're casually strolling in both directions. Yeah.

They don't know where to go, but they're definitely not drinking

and they realise that they're... And look. Ooh!

Yeah. This is a frustrated, frustrated elephant.

And it gets a little bit worse because he comes round this side.

ELEPHANT SNORTS

This is a bit of displacement behaviour, I think.

He's so cross with the buffalo, he can't do much about them,

so he's kicking the ground, look, still flaring his ears,

waving his trunk.

Both elephants and buffalo

came to the waterhole in the first 48 hours.

They are our most regular and heaviest drinkers.

And as the dry season intensifies,

they're encountering each other much more often.

The buffalo have strength in numbers,

but an elephant weighs up to 6,000 kilos

and the buffalo aren't willing to put up much of a fight...for now.

For these two giants, a changing climate and a growing scarcity

of water has potentially life-threatening consequences.

In the '90s, the number of buffalo were decimated in the Serengeti,

and the Maasai Mara because of drought.

So it's interesting to see that behaviour that created

this dominant presence.

That's for very good reason, I guess.

They really, really need that water.

In 24 hours, we measure that between them,

buffalo and elephant are drinking over 7,000 litres of water.

A natural waterhole might dry up with this level of demand.

But this one has a plumbed in fresh water supply

that we can keep topping up.

It's been tremendously busy at the waterhole overnight,

and as a consequence, the water level has gone down,

quite significantly, by at least two or three centimetres.

We are keeping track of water usage.

A centimetre drop in both pools

is approximately 2,000 litres of water.

I'll just turn this tap on.

You can hear it bubbling away.

WATER GURGLES

This water is from a naturally occurring reservoir

47 metres underground.

It's a sustainable water source

that's replenished every rainy season.

Wind turbines power the pump,

which can deliver up to 12,000 litres per hour...

..should we need it.

Over the next couple of days,

the important role our waterhole

is starting to play in the region

is underlined by a staggering

20 new species that come for a drink.

Including the hadada ibis,

which are native

to Sub-Saharan Africa.

The white-tailed mongoose,

which is the largest of the mongoose species,

reaching one metre in length.

Kirk's dik-dik, one of the world's

smallest antelope,

standing at just 35cm tall.

And a black-backed jackal,

that wastes no time

marking this territory.

So far, 40 species have visited the waterhole.

And on day ten, the tallest animals on Earth come for a drink.

Extraordinary animals, giraffe, absolutely extraordinary.

That looks like a terribly uncomfortable position to be in,

to have to drink, but that's the least of its problems.

The first thing is if you've got your head all the way up here

on a very long, stout neck and then you tip it down to drink

like this, all of the blood would rush down into your brain

and you would presumably black out straight away, but not the giraffe.

They've evolved something called a rete -

it's a tight bundle of arteries.

So the blood does run down the neck,

but when it gets to this rete at the base of the skull,

it slows it up so it doesn't flood the brain.

And then equally, when they tip their head back up again,

having had a drink, you would think that all the blood would drain out

of the brain and they would simply faint, but they don't.

They have valves in those blood vessels which stop that blood

cascading back into their body.

They've also got very strong oesophageal muscles.

I mean, look, it's now got to pump the water all the way from its lips

up to its body.

We tip water into our mouths and use gravity

to get it into our stomach.

This one's got a reverse gravity and that's what they do,

they've got very powerful muscles to suck that water up.

ELEPHANTS TRUMPET

It's only taken ten days for the waterhole to look like

an established oasis in Mwiba Reserve.

But on day 12, the area goes eerily quiet.

To help discover where the animals have gone...

..we've sent wildlife cameraman and tracker, Bob Poole,

to investigate.

Less than 100 metres away, he spots a potential reason

for the sudden quietness at the waterhole.

Right there, that's a pretty big animal, you see.

One, two, three, four, and the pad going to here.

Look at that...look at that distance in that.

It's definitely a big cat,

whether it's a lion or a big leopard.

Look at the size of this here.

You see?

So you can tell this is a very fresh track because you've got

a vehicle track here,

and right on top of that is a big cat.

Chris. Chris, do you copy?

Hi, Bob.

Hey, I've just found some big cat tracks on the road here.

Whereabouts are you relative to the waterhole?

Yeah, we're only about 100 yards away from you on the main track

to the north. Must have been...

I would have to assume it had to be early this morning.

I'd like to follow these tracks and see where they go.

OK. Well, I'll see you a bit later.

While a predator is in the area, only a handful of species will feel

safe at the waterhole, including the largest land mammal on Earth.

Elephants are rarely predated by big cats in Tanzania,

and this herd also has strength in numbers.

Look at that!

Oh, my goodness. How many? How many are we looking at?

OK, look. So that's eight adults.

One, two, three, four juveniles.

Look at that shot.

Look at the view we've got there. That's amazing.

Look at the little youngster.

A herd of 12 makes this the biggest number of elephants

at the waterhole so far.

Elephant herds are led by a matriarch, who is identifiable

by being bigger and older than the others.

This one is around 30 years old.

The youngest calf is just over a year old.

Elephants are notoriously protective of their young,

but this family are completely at ease with our remote cameras.

And they're the first animals to take a proper dip

in the waterhole.

But they're not just bathing -

they, like our warthog orphans, need mud.

And this is what it's about with the mud. They're chucking it on there,

it's going to evaporate the water out of the mud.

What's interesting here, though,

is that the elephants have very wrinkly skin. Yes.

So the mud goes into the wrinkles and therefore it takes

longer to evaporate.

And this means that the cooling process will go on longer

than if they had smooth skin.

But also, that wrinkly skin,

that increases the surface area and it helps with heat loss.

And, interestingly, the Asian elephants, of course,

don't have the same level of wrinkles in their skin...

No, they don't. ..because these guys need to cool down a bit more.

Mud can also act as sunscreen for elephants,

but it is often in short supply during the dry season,

which explains why this herd

is exploring every corner of the waterhole.

Right now we've got a very expensive camera very, very close...

SHE CHUCKLES

I know. ..to an elephant's feet. Great. Yeah.

Oh. Oh! It's...it's destroyed the camera!

SHE LAUGHS There goes the camera.

And immediately, we can switch to another one.

Look at that. ELEPHANT TRUMPETS

Oh, they're having fun, aren't they?

Oh, the calves are having a great time.

CALF HOOTS

There's a serious side to all this play.

This calf needs to get to grips with trunk control.

There are 40,000 muscles in an elephant trunk and it can take

calves over a year to master.

It's a vital skill, especially during the dry season

when water and mud are scarce.

It's interesting that they've come out of the mud...

..and now they're actively covering themselves in dust.

It's from one extreme to another, isn't it?

So this dust bathing, have you ever seen this before?

Yeah, I've seen them dust bathing... But after. ..but not...

No, not immediately after they've been made mud bathing, you know.

Potentially might be seeing different cultures here.

We know the same species in different parts of a country

will exhibit different cultures, just like we do. Yeah.

So this might be something that's a bit more unique. A peculiar habit

to this little group.

They get sticky and then they get dry.

They've started to move off, haven't they?

Can we see camera six?

The remains of camera six.

Look at the destruction of that!

It's still working, it's just a but dirty. It's worth it.

I mean, I'm not paying the bill, but from my point of view,

that shot was sensational.

After the elephant family leave,

the waterhole goes quiet again.

Bob is still following the big cat prints that are just 100 metres away

from the waterhole, but the trail has gone cold.

From now on, he'll have to rely on his tracking skills.

The guineafowls' alarm calling over there sounds like,

"Gah! Geh-geh-geh-geh-geh-geh!"

They give away predators all the time.

Perhaps there's a lion or a leopard right in this bush.

That noise right there - "Gah! Geh-geh-geh-geh-geh-geh!"

It's an alarm call.

GUINEAFOWL CALL OUT

Guineafowl are a ground-dwelling bird found across Africa.

They're known for being highly vocal when there are predators about.

Might go up there and see what they're cackling at.

WHISPERS: There's a lion right there.

There's a big lion right there, do you see it?

At the base of the tree right there.

Wow. We found it.

He's just waking up from a long day's sleep.

LION GROWLS SOFTLY He's huge.

He's wearing a collar so he's obviously being studied.

But he's a seriously big lion.

Tanzania is home to nearly half of all wild lions on Earth...

..with approximately 11,500 spread across the country.

Males are not always part of a pride, so this large lion

could be travelling alone.

It's likely that he's noticed the increased prey activity

at the new waterhole.

In the dry season like this,

wildlife gets concentrated around water points

and that makes it easier for lions

because they can ambush those water points.

And so that gives lions an advantage.

It's a good chance that this guy has shown up over here

because there's water nearby.

Here he comes.

Wow, that is a big lion.

And he's headed in the direction of the waterhole.

Sure enough, just after midnight,

the lion arrives at the waterhole.

By roaring... MUFFLED LION ROAR

..this male is claiming his territory.

The surrounding trees provide the perfect hiding place

for this ambush predator.

To find out more about this lion,

we're enlisting the help of Nuhu Mhapa,

one of Mwiba's top guides,

who's familiar with all of the big cats in the area.

I think I know this guy.

He's...he's called Kalumass,

and he hasn't been here for quite long.

It's just amazing that he has just come back.

How do you recognise him? Just from the size.

This is definitely Kalumass.

At over 250 kilos, Kalumass is one of the largest lions in Tanzania.

He's such a unique individual.

Scientists from the Tanzania Wildlife Research Institute

have been tracking his movements for the past two years.

What do you know about him?

Do you know how old he is and where he's come from, where he's been?

He was together with a pride of

four females, together with babies, with the cubs.

That was in 2017, right.

From there he disappeared and left the rest of the pride in the area.

He left the females and the cubs? Yeah, and the cubs.

There was no other male involved? No, no, no, no.

So he kind of abandoned them. Yep, yep.

That's quite odd, isn't it? That's what he did.

So he left them behind and he disappeared.

And then we got a call from our friends in Ngorongoro

and they said, "Hey, you know what? Kalumass is here."

He's gone all the way to Ngorongoro? All the way to Ngorongoro.

For the past year, Kalumass's tracking data shows

he's been in the Ngorongoro Crater area,

a neighbouring reserve teeming with wildlife.

But now, this unusual male lion

has chosen to make a huge migration

to Mwiba, walking over 80km.

We think he's about nine years old... Well, that's prime.

But, again, it's very impressive to see such a lion that age

and he's still being highly nomadic like this.

Which is, I mean, is quite extraordinary.

At some point, this lion's going to have to settle down! Well...

THEY LAUGH

He's getting on a bit.

Look, who's he got to contend with here?

OK. We've got these two males that just came in about

four months ago and they have

already met with the resident female here.

Well, he's an impressive animal, so they're going to have a

comeuppance when they meet him, aren't they? Absolutely.

It takes courage for whoever will see him to hold their ground.

Wow. It's going to be interesting to see what happens. Absolutely.

What does Kalumass mean?

Kalumass means "sneaky". Sneaky boy.

Sneaky boy? Yeah, sneaky boy.

CHRIS LAUGHS It's a fitting name - sneaky boy.

Yeah, he is a sneaky boy.

So, Kalumass has entered the territory of the Mwiba pride.

What do we know about them?

Well, we know there are a couple of males and a female,

and that she might have given birth in the last month.

No-one's seen any of those cubs yet.

But if that is the case, they're likely to be more protective

than ever of those cubs and this area.

Now, the den is not too far away from the waterhole,

so Bob has gone up there to see if Kalumass

made it to the den last night.

The Mwiba pride den is just over 3km from the waterhole,

a distance Kalumass the lion could have covered in half an hour.

On the way to the den, Bob spots lions in the bushes.

There they are,

two male lions.

Wow.

I've probably just had a run-in with Kalumass.

I think I see a little bit of a scar on one of their eyes,

which makes sense because they would really be defending their cubs.

Kalumass would kill them instantly.

There's a female. One of these two is probably the dad.

Kalumass is a great big male and he's formidable, even on his own.

But these two guys certainly would overpower him,

but it could have been quite a fight and they look

like they've had a rough night.

Kalumass may have been chased away,

but I'm discovering that his presence seems to have altered

the routine of the waterhole community

that has built up over the past 13 days.

Everything changed when the lion turned up.

You can see a shift in that schedule.

So we're noticing that some species are coming together.

So, for example, we're seeing the giraffe, the impala and the zebra

turning up together.

Now, that's partly protection in numbers, but there's something

really fascinating going on here, and it's that they're relying on

each other's strengths to identify the predators in the area.

Now, all of those three species rely upon their eyesight, but of course,

the giraffes can see the landscape much better.

And so those other two species are relying on those giraffes to ID

the predators, and that's why they're turning up

to the waterhole together.

Giraffe vision is so acute,

they can see movement from 2km away.

They are a life-saving early warning system for other animals.

The waterhole is getting busy again...

..and we're seeing more new bird species...

BIRD COOS

..including Fischer's lovebirds, that are only found in Tanzania.

Marabou storks, which are the largest stork species,

reaching up to 1.5 metres tall.

Colourful lilac-breasted rollers.

They symbolise peace in many African tribes.

And our first bird of prey -

an augur buzzard.

They often scope out waterholes

and predate on rodents and small birds that come to drink.

Adding the augur buzzard brings the species list to 61.

On average, we've had four new species a day come for a

life-saving drink in the dry season.

And despite predators being a constant threat,

there hasn't been any sign of hunting at the waterhole.

But just 3km away, Bob makes an ominous discovery.

I've just found this male kudu carcass in the drainage right here.

This riverbed runs around the waterhole.

It looks like predators are picking off prey as they travel

to and from it.

So interesting, because it's just been killed.

You can see the stomach has been opened.

Whatever killed this kudu

is probably going to come back to eat it,

so Bob is going to stake out the carcass.

After four hours of waiting,

Bob spots something moving in the bushes.

My goodness, that's incredible.

Wow, what a powerful animal.

It's the Mwiba pride lioness that's made the kill.

The males are nowhere to be seen,

but this meal isn't all for her.

Whoa! Look at that, look at that

right over there on left side of the screen.

Cubs coming down the bank.

Whoa.

That's incredible. Look at that.

I haven't seen any other lionesses.

So it means she's all alone, at least as far as I can tell.

Lion prides vary in size,

but usually have up to a dozen females.

A lone mother like this is highly unusual,

especially with two cubs that are just six weeks old.

That's a really tough thing for a lioness to be all alone

like that with two cubs.

Very difficult for her moving forward.

Only about 50% of the cubs make it when their mother's alone like this.

The waterhole could become a very important focal point

for this lone mother, as it provides a reliable and potentially

easy source of food and water.

It's been 14 days since the waterhole was built.

The species list is now up to 70.

There are still new animals coming,

but you have to look harder to find them.

I've spotted a direct physical relationship between our HQ here

and the waterhole all the way down there, 200 metres away,

and it's in the form of mud.

Look up here in the apex of the tent.

This is the nest of a parasitic wasp,

and it's made this little muddy chamber.

This is it. She's come in. Look at this.

Look at that! Now, what an insect.

Now, typically, they like to hunt caterpillars.

She'll sting it and paralyse it -

critically, not kill it -

and entomb it in that mud nest whilst it's still alive.

Then she'll lay an egg on it, then she'll go and catch another.

And when the nest is filled, she'll plug that little hole

and those eggs will hatch.

And they'll eat the non-essential organs first, thus keeping

them alive - fresh meat, you see -

and then they'll pupate and hatch out.

I've got to tell you, these are insect super predators.

And the thing is, she's only able to do this because of our waterhole,

because you can't make a nest like that without water,

cos you need top-quality mud.

So we provided a resource for elephants, buffalo,

all of those birds and also some really smart insects as well.

The parasitic wasp takes the species list to new highs.

We're currently at 71, and the interesting thing is,

it's a wide variety of species.

You've got small birds, all the way up to

the great African elephant and they're all here sharing this water.

But already that's really impressive,

and it will be really interesting to see how that number shifts

as the seasons progress.

In just two weeks, a fully-functioning ecosystem

has sprung up at our waterhole.

ELEPHANT TRUMPETS

From butterflies to buffalo

and lapwings to lions...

..we've seen a wild community build from nothing.

ZEBRA SNORTS

But their lives are going to get tougher.

In two months, this corner of Tanzania enters

the hottest time of year.

We'll be back to follow our waterhole animals for

two critical weeks when the heat is at its peak.

Next time... Temperatures surpass 40 Celsius.

Tensions reach boiling point when a new predator swarms the waterhole.

Hyenas take over and invade our camp.

There's a trail of footprints right down to the opening of my tent.

The species list expands with an unexpected African giant.

To think that we could have made a home for a hippo.

Now, come on, I'd put that on my CV!

And for one extraordinary elephant,

the waterhole becomes a vital lifeline.

That's a severed trunk. It's amazing that he's still surviving.

In the baking heat of the African savanna...

..as rivers dry up...

..all animals flock to the water hole.

We've never fully understood

how a single water source can support so many competing species...

..so we're doing something ground-breaking.

Welcome to Tanzania and to the Mwiba Wildlife Reserve

and to this unique water hole behind us.

We are working with the reserve to create the world's first water hole

with a built-in specialist camera system.

This water hole has a half-submerged filming hide

right in the middle, and it's rigged with remote cameras

so we can see every angle of animal behaviour like never before.

Last time, in the peak of the dry season,

our cameras captured

over 70 species.

Look at that! Extraordinary animals.

This emerging ecosystem quickly saw

wildlife working together in surprising ways.

They're relying on each other's strengths

to identify the predators in the area.

Now we're entering the hottest time of year, when temperatures soar

to an unbearable 40 degrees.

Turning the water hole into a lifeline

for the reserve's most vulnerable...

That's a severed trunk. It is amazing that it's still surviving.

..and making this precious water source a target

for a clan of notorious predators.

They must be just out here.

I can't see them. It's completely black.

This is the story of life and death at the water hole.

We built our water hole in Mwiba Wildlife Reserve...

..south of the Serengeti, 500km from the east coast

of Africa in Tanzania.

This is a safe haven for Africa's most iconic species.

The long, dry season is drawing to a close, and we've returned

for two critical weeks at the hottest time of year...

..when water is an even more essential resource.

After five months of crippling drought,

food is also in short supply.

The grasses have died off and acacia trees are almost bare.

The water hole is more vital than ever.

ELEPHANT TRUMPETS

We're back at the water hole.

We're back at base camp at the hottest time of year.

Yes, the big question is, what effect will this raging temperature

have on the wildlife here

now that all of the other water sources in the environment

have dried up and only our water hole remains?

The water hole is now the main source of fresh water

for 15,000 hectares of the reserve.

There's very little shade,

so getting here can be exhausting for wildlife -

but, when water is in such short supply,

it's worth it.

And on the first day of filming,

the water hole draws in a thirsty animal

that we haven't seen before.

WHOOPING

Spotted hyena are one of the most successful predators

on the African savanna...

..and an exciting new addition to our species list.

I love hyenas. Look at that! Oh, look at that!

Now, we didn't see them at all last time.

It's just happily drinking, it's on its own.

We're looking at the footage to try and understand

what this typically nocturnal animal

is doing here during the day.

It's full, right? Yeah. It's just eaten.

It's eaten.

Look, it's got a great big tubby belly full of meat, there.

Hyenas often get thirsty after feasting on a carcass...

..and it looks like this individual may have made a kill nearby

in the past 24 hours.

It's pretty comfortable, isn't it?

Out in the open, it's very confident.

I think this is probably an animal

that's getting to know this water hole,

knows the lie of the land.

They live in clans

and, often, you know, pretty numerous

in terms of, you know, the numbers that you're going to get there -

groups of 20, 25 not uncommon.

Of course, they have this reputation as scavengers,

but they are hunters as well, they're really skilled hunters.

And, actually, it's more likely that a lion will scavenge off them

than they will scavenge off a lion.

They have such a bad reputation

and yet they're actually kind of gorgeous

and definitely really intelligent.

Yeah, smart, incredibly complex social system,

governed by the females, amazing behaviours,

and an essential part of the ecosystem, of course.

It's such a privilege to see one out during the day,

isn't it, though, cos it's so unusual?

And I guess that's the advantage of having all these cameras.

But, for other animals, however thirsty they might be,

the presence of this predator is likely to make them nervous

about coming to the water hole.

Only time will tell if this hyena is here to stay.

20 cameras are positioned around the water hole.

Calling up the footage offers a unique insight

in how the heat is affecting the habitat.

This is going back to the last time that we were here.

And if we cast forward... It's already quite dry.

Wow. OK, that got drier!

So there's lots of dry vegetation there, but the vegetation is there.

If you cut to the next one.

Right. It's really barren.

It's so much drier. It's like desertification, basically.

It is. The grass, the ground floor, has dried out.

It's been eaten.

In terms of what's available for herbivores to graze

around the water hole,

there's absolutely nothing.

All that is left to eat

are a few remaining leaves too high to reach...

..and roots from dead grass.

Animals have to travel further or dig deeper

to find anything nutritious.

The shape of the water hole's changing a bit, as well,

whilst all the animals have been coming.

A little bit on the top corner, there, where it's shallower.

Presumably, they're just wallowing, taking some of the material away.

At this time of year,

wallowing is one of the main ways

animals cool down.

They are hungry and tired, desperately seeking shelter.

And it's this that allows predators to thrive.

So, it's not surprising that, on our first night,

we add new carnivores to our species list,

including servals.

They are small savanna cats,

but are one of the most successful hunters in the cat family.

They can leap up to three metres in the air to catch birds mid-flight,

and they're known to hunt up to 16 times a day.

The elusive African wildcat rarely drinks water,

but uses its acute hearing to precisely locate prey

around water points.

Spotted genets have retractable claws to hunt in the trees

and down on the ground.

Now the water hole has become a regular feature in the landscape,

smaller predators have plenty of hunting opportunities

as small prey like rats and hares come for a drink.

A few hours later, we get further proof that the water hole

is a magnet for animals from far and wide.

Look - hippo! Hippo are one of the most powerful animals in Africa,

with canine teeth that can measure up to half a metre in length.

This was something I really wanted to see in our water hole,

and it was always on the cards.

You would think that, in the foreground,

that's a source of great temptation...

Oh, look at that! ..for a lonely wandering hippo.

They do move quite large distances away from water,

looking for new water, of course.

But this hippo isn't searching for water.

He's looking to graze.

Hippos walk almost 10km at night,

eating up to 40 kilos of grass.

Oh! To think that we could have made a home for a hippo.

Now, come on! I'd put that on my CV.

With so much of the shrubbery dried out, life is tough

for many of the animals here...

..but insects thrive

in this stifling heat, with the humidity helping them breed.

This means lots of new insects are spotted buzzing

around the water hole.

And insects aren't the only new visitors. Migratory birds,

that have often travelled great distances,

are also dropping in, including...

..the steppe eagle, which breeds in Central Asia

before travelling up to 10,000km to Africa.

HONKING

And Egyptian geese, that pair up for life.

Once one dies, the other mourns in seclusion

and often refuses to mate ever again.

HONKING

A lot of the birds flocking to the water hole now

are not coming to drink or bathe.

They're searching for food.

This is yellow-billed stork. You can see how it got its name.

I've got a soft spot for yellow-billed stork.

Now, when it comes to what they eat, they are pretty much opportunists.

These animals will eat a frog if they find it,

they'll eat a small snake and a lizard

if they find it, they'll eat fish if they can find them.

And that's what they're looking for here.

What they're doing is they're putting their beak into the water

and they're holding it slightly open so that, if anything swims in,

they can snap it tightly closed pretty quickly and capture the fish.

Super views! Look at that. Amazing.

I just feel a little bit sorry for them,

because we've only just made the water hole

and, at this point, there aren't going to be any fish in it.

When the rainy season arrives and the landscape floods,

new waterways will open up for fish to find their way to our water hole.

But this won't happen for at least another few weeks -

though no-one has told the storks that.

It's sad, really, isn't it?

It is said that sometimes the eggs of fish

are carried on the feet of water birds -

ducks and things like storks.

You never know.

These animals may have brought the very fish that they might eat

at some stage in the future on those, their feet.

Birds are now the most frequent water hole visitors during the day.

It's a far cry from the middle of the dry season two months ago

when daytimes were busy with many more species.

I have been studying the data to see how much things have changed.

So this here is a plot of all the animals' -

and not just some animals, but all the animals' -

arrival times at the water hole.

Now, we're comparing our data from the dry season

and now the hottest time of year.

So, when we were here last time, you were looking at two peaks -

the animals were mostly coming during the day

and then again at night.

But now you're seeing a complete shift.

Buffalo that would arrive at dusk

are now waiting until darkness at 8pm

before coming for a drink.

Elephants who regularly visited during the heat of the afternoon

are now mostly arriving around 9pm.

Zebra, which used to come around 11am every day,

are now turning up more frequently

between the hours of 2 and 4am.

What you're seeing is the animals are preferring the night,

and, so, suddenly night has become the new rush hour.

But night can be a dangerous time to drink.

Mwiba is home to some of Africa's top nocturnal hunters,

like leopard, lion,

hyena and wild dog.

On the fifth night, the highest number of predators yet

comes to the water hole.

HYENAS CALL AND BARK

The spotted hyena returns, and it's not alone.

OK, there's a clan moving in. Look at that - seven.

Six. Now there's seven at the moment.

There's eight there now.

I wonder if it's because they've basically just built up

the confidence to come in here

or whether they have moved into the area.

That's unlikely cos they have quite stable ranges

and denning sites.

They do go wild sometimes. They do.

And they've got a remarkable vocabulary - all sorts of whoops

and whistles and barks and howls.

Spotted hyenas are known as laughing hyenas

because they have a distinctive call that sounds like human laughter.

They can make more than ten vocal sounds, but these can be modulated

to create even more meanings -

and they can hear each other's calls from up to 5km away.

But, clearly, if they're moving through the bush at night

and they're moving through thick bush,

it doesn't matter how good their nocturnal vision is.

They're relying on their sense of smell

and, to communicate with one another,

those calls that we hear so frequently.

THEY CALL

They're not considered favourably, are they, really? No, they're not.

They're looked down upon by many African cultures and, certainly,

you know, Western cultures as well.

I think, because of their scavenging nature, their nocturnal habits,

we're always fearful of things that come out at night -

they're difficult for us to see and understand.

Hyenas are highly territorial.

Now that they've discovered the water hole,

their mere presence is a threat to other animals

relying on this crucial resource.

THEY CALL

To help understand the hyena's impact

on our emerging water hole ecosystem,

I talk to Dr Meredith Palmer.

She's been studying Africa's carnivores for more than a decade.

Meredith, we've got a number of hyenas here.

The most we've seen at the water hole is eight -

and, at the moment, it's dry.

Lots of herbivores are coming to drink and then hanging around.

That must be ideal, therefore, for the hyenas. Yeah.

So, having prey in high abundance in a landscape

tends to favour hyenas.

Hyenas are apex predators in this system,

exerting a lot of top down control on what's going on.

Spotted hyena are the most abundant large carnivore in Africa,

with an estimated population of 47,000.

A lot of their success

comes from their complex and highly adaptable social groups.

Clans consist of many non-related, low-ranking individuals

led by an alpha female.

Working under her leadership,

they seek out areas where prey congregate...

..like our water hole.

They know these animals are going to be here.

The water hole is very good

because having a high abundance of prey

allows their clans to grow to very, very large sizes -

and if your clan is 40 or 50 individuals,

it's always going to win against another species.

Dr Palmer's research suggests

that it's likely there could be even more hyenas nearby

and, once hyenas are established,

the water hole becomes a dangerous place to be.

Which could be why, following the hyena clan visit,

days and nights are a lot quieter.

To find out where all these hyenas are coming from,

cameraman Bob Poole's been searching the area.

He spotted a hyena den with three young cubs

just 2km from our water hole.

There, right there.

There they are. There they are, look.

One, two, three.

And that's about the maximum litter size

for one female, isn't it? Yeah.

25% don't get through the first month,

and they're born with incisors and really sharp teeth

and their eyes open -

and as soon as they're born, they're fighting one another.

I guess that's one way to ensure that the strongest survive.

But it's pretty brutal.

But by the time they get to this stage, it's all sorted -

they already know who's top hyena.

Bob and I take a remote camera to see if we can get a closer look

at these cubs without disturbing them.

It's the same as those that we're using at the water hole.

We can remote control it from the vehicle here.

We can pan and tilt and focus and expose,

and we'll get a view of it here.

Bob here is a bit underexposed at the moment.

But the purpose of this, of course,

is to allow us to learn a little bit more about these young hyenas

close to their den.

Yeah, the cubs are still there.

They haven't minded us...

..being this close.

You can see here how curious these cubs are.

We're only about, I don't know, six, seven metres away

from the entrance to the den.

It's in their nature - they're opportunistic animals.

So they're always on the lookout for new things.

ENGINE STARTS

We deploy our camera and move back about 30 metres.

These are likely to be all of them.

I think the same litter. They're mobile pretty quickly,

and then they need to get on their feet and get moving.

So the female hyena has the most fat in her milk

for any terrestrial mammal.

By eight months, they're showing hunting behaviour,

and, within a year, they're out hunting with the adults.

The arrival of an adult female lets us spot something remarkable.

There it is - there, look.

A newborn hyena cub.

It's much smaller.

It's gone down. It's just gone down? We'll see it again.

That was much blacker and much smaller. It's tiny.

Yeah, yeah.

But when the female heads underground, it doesn't take long

for the older hyena cubs to start investigating our camera.

One of the cubs is now just walking down the cable line,

having a good sniff.

Oh, hold on.

This is the cable being pulled by the other one.

There it is - look, look.

It's got the cable.

BARKING

I knew that this would happen.

How long's that cable going to last?

They've all got the cable. It's gone.

For some reason, it's stopped recording and gone back to this.

There's just no input.

Oh, they've pulled the cable out.

I don't believe it!

They have. They're chewing it.

They've pulled it out of the back of the camera.

That's not good at all!

That's a shame, because they'd just plucked up the courage

to come right up to the camera,

so the camera did give us the opportunity

to find out a bit more about them.

I think, from our point of view, what's going to be interesting is,

you know, will these be the hyenas of the future

that might visit our water hole?

After a few months, they will go out with those adults,

and there's every chance that they'll turn up down there.

Choosing a den so near to our water hole

and therefore close to prey

is a key survival strategy

that will help this clan grow strong in numbers...

..but the sight and the sound of these powerful predators

will keep many other animals that rely on this area for water away.

However, large animals like this male elephant

are too big for a hyena to take down.

And now that water is scarcer than ever,

the water hole has become a lifeline for one extraordinary individual.

We've seen him for over four years now.

Mwiba guide Nuhu Mhapa helps me to identify him.

It's amazing that he's still surviving with such a trunk

that has been cut by a snare, set by the poachers,

intending to catch some of the wildebeest or zebras and so forth,

but, as the elephant moves across the bushes,

grabbing these grasses,

then it just kept cutting the trunk, so, it's painful,

but he has been with that kind of wound for quite some time now.

Those trunks are so important. They have multiple uses -

they are a hand when they eat, they do help the elephants drink,

obviously, they suck it into their trunks,

and then they put that into their mouths.

But also they use it to signal to other elephants.

Life is challenging for this individual. Using their trunks,

elephants are capable of lifting over 300kg,

something he will never be able to do.

HE RUMBLES

Thankfully, he can drink.

But at this time of year, many natural water sources have dried up

and are harder for him to reach.

Water deep enough to wade into will help him to survive.

It must be also really sad when you see this happen.

It is, it is.

And especially when you consider that these animals,

they are long-living animals,

and you start to imagine how hard it is for him,

just from this young age all the way to 16 years old.

So it's tough. It's very sad for us

because we humans have caused these kind of problems.

So he's been affected very much.

So we've seen the effect that the predators are having here

at the water hole, but there is another species

that seems to be bullying just about everything that comes for a drink.

It wants the resource entirely to itself,

and our cameras can throw some light on the matter.

QUACKING

Egyptian geese are aggressively territorial at this time of year

as breeding begins, and they've started fighting

over the water hole.

A mating pair violently protect this patch

from other geese.

And it seems they're also a surprisingly intimidating presence

to much bigger species.

THEY HONK

Not the quiet drink this giraffe was hoping for.

Even predatory birds, like the huge martial eagle,

are disturbed by this boisterous couple.

THEY HONK

Whilst domineering geese are unexpected,

it means our species list has stopped growing at number 82,

as animals seem to be scared away by hyena at night

or put off by geese during the day.

HYENAS CALL AND BARK

Over the next few nights, hyena visits increase.

HYENA HOWLS

HYENA CALLS

And they're gaining confidence.

One night, a hyena appears with evidence that it's been hunting

very close to the water hole.

It takes some scrutiny to determine what this individual's doing.

It approaches the water hole, there,

carrying the limb of something that it's either killed or scavenged.

Leg of wildebeest it's got in its mouth there.

And rather than stop on the side, put it down and have a sip,

it wades into the water with that limb.

Now, some animals will wash their food,

but it's not washing the food, I don't think.

They will stash their food, hyenas.

They will cache their food.

You can see it's got a pretty much full belly.

It's probably eaten as much as it possibly can at this point.

It simply wades in and then it comes back out.

Maybe it was thinking about caching it in the water

and it had a change of heart and went and hid it in the grass.

Sometimes, animals do the strangest of things.

Now think about your own behaviour.

Sometimes, you do things which are out of kilter

with not only human behaviour, but your own.

Perhaps this hyena's just got a leg quirk.

And that's the real joy of having cameras set up like this -

we get to see things like this

that, in a lifetime of personal observation,

you're highly unlikely ever to get to watch.

HYENAS CALL AND BARK

With our camp only 800 metres from the water hole,

we're having more encounters with the hyenas

than we bargained for.

The crew even spot one looking for food right in front of them.

And they're brave enough to visit our tents,

howling through the night.

HYENAS CALL AND HOWL

One of the great joys of sleeping in a tent

in sort of the African night

is not sleeping through the African night

because there's such a cacophony of noises out there -

and you're laying there, thinking, "What's that? What's that?"

but you don't have to wonder about the hyenas,

and there have been a lot of hyenas in the camp.

In fact, when I got up yesterday, there was a trail of footprints

right down to the opening of my tent, and I love that.

I love the fact that you're sleeping that far away from a large predator.

You never get that feeling in the UK.

HYENA HOWLS

They are sticking to that whooping sound that they make as opposed to,

well, more of the laughing sound, but it is...

..it does sound like it's everywhere

and it's been going on for a few hours

and we are really close to the water hole.

They're even using the same trails as us to get in and out of the camp.

But not all animals are threatened by the hyenas

and, over the next few nights, we add more new species to our list.

Bats dive-bombing the water hole

can eat up to 3,000 insects a night.

CROAKING

Toads absorb water directly through their skin

so they don't need to drink.

CROAKING

This morning, a Mwiba guide

has told Bob a carcass has been found close by.

There's been a kill right here in camp. It's right down here,

just a few hundred metres, and we need to go check it out

because apparently it's a full grown adult waterbuck,

which is a sizable animal.

The carcass is just 600 metres from the water hole,

so, Bob is keen to find out

what might have been hunting in the area.

It's gone - like, gone.

There's nothing here.

Can't wait to see the camera trap footage.

It's remarkable, really. This carcass is gone.

There's not even any evidence it was ever here.

There's a tiny bit of a gut pile contents, no stomach.

Just looking to see if there is any lion prints.

So far, I only see hyena.

Hyenas will just rip this carcass to pieces,

and when you look at their jaws, they're extremely wide here,

and they have very strong muscles on the top of their heads,

and they're able to crack right through bones

and they actually eat them.

That's why, when you see their dung, it's often just white

because they absorb so much calcium from the bones that they eat,

but it just goes to show you that nothing is wasted out here.

When the Mwiba guide found the carcass last night,

he placed a camera trap on it.

Bob wants to confirm if this is a hyena kill.

Guess what - they came in the daylight.

OK, here we go, hyena coming on.

Oh, yeah. Beautiful shot.

Staring straight at the camera now.

Oh, wow. Here it goes.

Ah!

One hyena, just struggling to drag that,

but doing it.

Oh, that's cool.

Flipped it over.

I was thinking it would have been a whole, you know,

group of hyenas that came on first,

but it's just one individual.

But it shows you the strength of this animal,

by dragging that huge carcass

and consuming tremendous amounts of meat.

A hyena can eat 15kg of meat in one go,

which is 25% of its body weight.

Phenomenal to think of.

Wow. This guy's really lucky.

He's not having to share it at all at the moment.

Oh, hang on.

There's another hyena in the background there.

Oh, here we go. Ha-ha!

He's been discovered,

and we've got one, two, three, four hyenas.

They're really ripping into it.

All right. This now makes sense.

I didn't think one hyena could eat that whole thing.

HYENAS CALL AND BARK

One has just taken off with a hindquarter,

so that's how it goes.

Bit by bit, the thing is gone.

You know, they can devour this carcass

in a very short amount of time.

With spotted hyena working together to take down large prey,

it looks like they're now the apex predator dominating the area.

Earlier in the dry season,

we discovered a local lioness

was also hunting near the water hole to feed her cubs.

But we haven't seen her or the cubs since we've been back.

Could the hyena have driven them away?

To find out, Bob is going to check the camera traps

we placed around the lion den,

3km away.

I'm anxious to see what we've got here.

There's the mother, right there.

She came in looking quite defensive.

HYENAS CALL AND BARK

Wow.

Hyenas.

There they go, chasing upriver,

which is the direction where the lion was.

HYENAS BARK

Hyenas will kill lion cubs, any chance they get.

HYENAS CALL AND BARK

To discover if the lioness and her cubs are still alive,

Bob has to extend his search.

He spots evidence of lions

over 16km from the water hole.

There's a carcass right there.

Maybe she's made a kill in here.

There she is.

I guess we just have to stay here and see what happens.

Oh, oh, oh!

I just saw movement there.

Oh!

The cubs are right there.

Oh, my God!

They're right there.

I can barely see it.

Oh, my God.

Let's see how many...

One...

..two...

..three little cubs.

You know, you get so invested in this stuff

and your mind plays tricks with you, like, they're dead,

and it's like, wow, that's just...

It actually becomes quite emotional, you know, to see them again.

The lioness has successfully moved her cubs away from the hyenas.

Lion territories can range in size from 20 to 600 square kilometres,

and cubs are often relocated several times a month to keep them safe.

But other animals can't move out of the area so easily...

..and have no choice but to risk their lives

coming to the hyena-dominated water hole.

This vervet monkey mother needs to drink every day

in order to keep producing nutrient-rich milk for her young.

The baby clings on tightly whilst on the move,

something they're able to do from birth.

The rest of her troop are nearby to keep watch.

Vervet monkeys raise high pitched alarm calls if they spot danger.

They use a different call for each predator

to signal different escape strategies.

With the coast clear,

she makes it to the water hole.

The baby gets all the fluids it needs from its mother's milk,

so as long as she gets enough water, the baby will survive the heat.

On day 12, it's 39 degrees,

our hottest day yet.

And a rather unexpected new species

turns up at the area around the water hole.

COWS MOO

Ella, look at this.

Yeah, they're not supposed to be here. Trespassers.

Right, so these cows are not supposed to be in this area.

It's a protected area.

Around the outskirts of Mwiba,

there are many Maasai villages that keep livestock.

Their cattle are banned from entering the reserve

in order to stop overgrazing.

But there are no fences in Tanzania between nature reserves

and human populations,

so enforcing this ban is difficult.

In this wild place where people and animals live side by side,

there are no easy solutions,

and at the toughest times of year, like now,

trespassing is likely to increase.

Where's the person that's looking after these cows?

Or is there nobody looking after them?

No, there should be someone looking after them,

because, obviously, they're potential prey

and they are currency, aren't they?

You know how valuable they are to the local community,

so they don't let them ramble and roam at will.

Look, there you are. There's the human, there.

See, the thing is, he's going to get fined. This is the thing.

He will get a heavy... A fine.

Yeah, he'll get a heavy fine for being in this area,

and so he's taking a massive risk, being here.

I guess I'm wondering why he's...

..why he's brought them in, when there's such risk.

Perhaps this is his only choice.

It's either bring those animals in here,

or they're going to die of malnutrition... Yeah.

..and he's going to lose his livelihood

and perhaps even the lives of some of his family.

Presumably, he's taking the risk of that fine

simply because there isn't an alternative elsewhere.

Eventually, a Mwiba ranger escorts this herd out of the reserve.

The presence of these cows

shows just how harsh the environment can be at this time of year,

and why water is such an important resource for all.

THUNDER RUMBLES

Finally, after five months of drought,

three millimetres of unexpected rain brings some relief.

THUNDER RUMBLES

It's not enough for grass to grow or natural water holes to fill...

..but it does lead to a sudden explosion of life - insect life.

Look at this beauty. Huge beetle.

I notice that the tent has become a bit of an insect trap,

particularly at night, with the lights on.

They're drawn to those lights,

and they're typically more active at that time.

It's cooler, it's more humid, best time to be flying around,

particularly if you're a large insect like this.

We might call it a longhorn beetle.

It's got these characteristic long antennae here,

typically extraordinarily sensitive,

for finding members of the opposite sex.

And given its size, I should imagine that this creature

has been living as a grub, perhaps inside some rotting wood,

for a number of years. And, having emerged as an adult,

their job is to mate and then disperse, lay eggs and die,

get eaten by something bigger, perhaps even more interesting,

something that might happen in the space of just a couple of weeks.

And on that account, I'm going to put it outside

so it can do its business.

ELEPHANT TRUMPETS

Our water hole has become a lifeline for many species,

from the smallest to the largest...

..including the elephant with half a trunk.

He has returned to our water hole,

and this time he's with a herd.

Elephants are highly social,

and other members of the group are keen to interact with him.

They use their trunks to communicate,

smelling and touching each other's mouths.

It's essentially an elephant handshake.

Half trunk does his best to return the gesture...

..making a vital social bond...

..and confirming him as one of the family.

Over the past two weeks,

we've seen hyena numbers increase,

and their visits intensify, both day and night,

but we still don't know exactly how many there are in this clan.

We're excited to have spotted hyena around our water hole,

but it would be great to know how many there are.

The trouble is, counting them can be really tricky.

Firstly, they're nocturnal, of course,

which makes them difficult to see,

and then they move around in fluid social groups.

So, if you count six here,

two of them could be from the four that you later count over here.

We clearly need a different method.

We need it to get dark and we need to bring the hyenas to us.

Dr Meredith Palmer has carried out similar experiments

all over the Serengeti...

..and can help us shed light

on how big our water hole hyena clan might be.

So, Meredith, how are we going to try and count these animals?

So, we're going to do a call up tonight.

We're going to play some sounds that might intrigue the hyenas

and bring them out of the bush

so that we can get a good look at them and count them.

We're going to start by doing the sounds of prey animal in distress,

playing the sounds of a warthog that's having a very bad day.

If you're a hungry hyena, this might be the kinds of noises

you would come and investigate to see if you could get a meal.

We'll then play some hyena social noises.

So we'll play the long whooping calls of the hyenas,

and the calls I have are calls of hyenas that don't live here.

They're strange hyenas. They're foreign hyenas.

And if this was your territory, if you were a resident hyena here,

you would definitely want to come investigate

whatever strangers might be coming through.

OK, so now we're playing a warthog having a very bad day.

In terms of sort of disturbing their behaviour, the ethics of this,

you know, we are playing an artificial call,

we're moving them around the environment,

but presumably only for a brief period of time

over a short distance?

This is very noninvasive.

This is a very minimal kind of experiment

to study their behaviour and their population.

OK, shall we give a go, then? Let's do it.

Let's wind them up with a bit of wounded warthog.

WARTHOG SQUEALS IN PAIN

Hyenas come together en masse for two key events,

either for a feast or when they're trying to defend their territory.

Tonight, our two different calls

are attempting to lure them in for both.

If we are able to bring up any hyenas,

we can see the different spots, we can see the different scars,

and we'll be able to identify the different individuals that come up.

OK, what about range?

How far away...from how far away can we bring them in?

So, we're playing these calls quite loud.

The hyenas should be able to hear calls played at this decibel

for about 3km.

If they're within that radius, they might come investigate.

It's pitch black.

So we can see is the infrared camera feed on the monitor.

And within just four minutes,

the first hyena turns up.

WHISPERS: Didn't take them long to arrive, did it? Came very quickly.

Yeah, they must have been in the immediate vicinity,

which points to the fact that they're using this water hole.

So they'll be occupying this area.

Their quick arrival suggests they live nearby,

quite likely at the den I visited with Bob.

Oh, there's two of them. Oh, there's two.

HYENA BARKS

That's them... There's one over here.

Geese aren't moving, are they?

They're absolutely frozen solid.

They must know those hyenas are there.

They're moving...

There's another...

Around the back... Oh, there's another one here.

There's three. Three, at least. Yeah.

Hyenas are highly social animals,

and their clans have very complex hierarchies.

When two hyenas meet,

the subordinate animal lifts its leg to the dominant hyena

so it can examine its genitalia.

There's one close here, though.

That one must be just out here.

The dominant female usually has her tail upright

and the subordinates keep their tails and heads down.

HYENAS CALL AND BARK

We're hoping to work out which hyena is the leader.

There's another. There's another.

Four. Four, yeah.

Five, six!

HYENAS BARK

They must be just out here.

I mean, I can't see them, it's completely black here.

We're using infrared light.

Those hyenas can't be any further than...

..I don't know, six, seven, eight metres away, just out here.

They sound so close. Yeah.

HYENA BARKS

And more keep coming.

You can see them now. Look, cos they're here, aren't they?

The whole crew. Yeah.

They're surrounding this...

HYENAS CALL AND BARK

It's amazing to think that these fantastic animals

are just a few metres away out there.

How many are there at the moment, Meredith?

11. 11?! Wait, there's one more coming in.

11? Are you serious?

That's the most we've had here, then.

Yeah.

With such a large group gathered on camera,

we can work out that these two smaller hyenas

are the most dominant,

by the way the others are behaving around them.

God, I wish I had infrared eyes, I really do.

Once the calls stop,

this clan soon moves on.

That's the last one, look, dashing off into the darkness.

Yeah, what about that?

Top work, Meredith. That was really good.

It's a brilliant sighting.

With 11 hyenas coming to the water hole in just 19 minutes,

Meredith's previous research suggests that it's likely

there are other hyenas in the clan

who are out of range or at another kill.

She estimates there could be as many as 25 in total.

I've got to say, what an extraordinary experience.

It was so enigmatic, knowing that these large, powerful predators

were just a few metres away in the darkness.

We could hear them.

We couldn't see them.

Sadly, we couldn't smell them.

But they were just within reach.

Amazing. Amazing.

This hyena clan has taken over our water hole,

and I've been compiling the data to look at the impact

of their ever increasing presence.

We've been studying the number of hyena visits at the water hole,

and what's interesting is that these visits have continued to increase.

We spotted 73 visits.

Hyena now come nearly every day,

but with water running desperately low across the reserve,

new animals still risk visiting this crucial lifeline.

We've had an additional 17 species,

including the hippo and the serval.

That means our total count of animals

that have turned up to the water hole

since we opened it just a few months ago is 88.

Over the past two weeks,

we've seen life at the water hole completely transform.

But everything is about to change once again.

The rains are already here, a month earlier

and a lot heavier than usual.

In the coming months, more rain will fall on Mwiba

than in London in a year.

A deluge that will have a huge impact on the water hole.

We're back during the height of the rainy season,

when there is an explosion of life.

One of nature's greatest spectacles,

the wildebeest migration, arrives,

bringing an influx of new prey and predators.

It's just incredible to witness.

And our water hole ecosystem

enters an important new stage of its evolution.

All of the animals that have been coming here have been visitors,

but now we've got some residents.

In the baking heat of the African savanna...

..as rivers dry up...

..animals flock to the water hole.

But we've never fully understood how a single water source

can support so many competing species.

So we're doing something ground-breaking.

Welcome to Tanzania and to the Mwiba Wildlife Reserve

and to this unique water hole behind us.

We're working with the reserve to create the world's first

water hole with a built-in specialist camera system.

This war as a whole has a half-submerged filming hide

right in the middle, and it's rigged with remote cameras so we can see

every angle of animal behaviour like never before.

When we were last here at the hottest time of year...

..hyenas ran wild.

How many are there at the moment, Meredith? 11.

11? Serious?

Now it's the rainy season and the water hole ecosystem

is facing its biggest change yet.

Up until this point, all of the animals that have been coming here

have been visitors, but now we've got some residents.

An explosion of life brings new species flooding in.

It's the most fascinating example of swarm mentality in mammals.

And we reveal how our water hole is set to be a lifeline

for generations to come.

From up here you get a great view of the ecosystem.

This is the story of life...

..and death at the water hole.

We built our water hole in Tanzania,

500km from the east coast of Africa,

south of the Serengeti.

Mwiba Wildlife Reserve.

After five tough months of drought, the rains are finally here.

More rain will fall over the next three months

than in a year in London.

We're at the height of the rainy season

and over the last two months,

the whole landscape has completely transformed.

Yes, just look at this.

The dusty old dry river has gone.

Replaced with this fresh flush of bright green grass.

And this has radically changed life here at the water hole.

On average, it rains every day for four hours.

These regular downpours trigger over 200 species

of savanna grass to grow.

Mwiba's 53,000-hectare reserve

is now a lush, all-you-can eat banquet for herbivores.

In this time of plenty, many animals now have their young.

Over half a million mammal babies

and more insects than it's possible to count

are born at this time of year in the Serengeti ecosystem.

To see how this explosion of life impacts the water hole,

we'll be recording 24/7 for the next ten days.

I'll be collating the data behind every visitor...

..and adding to our species list that's already at 88.

And I'll be replaying footage to analyse the complex behaviour

behind every interaction.

But before we could start, we had to do some repairs.

When we first came back, the rains had been so heavy,

the edges of the water hole were caved in.

We called in the Mwiba construction team to help get

the water hole up and running again.

Our filming hide also suffered in the deluge.

You see these lines? Well, these are water marks.

Yes, the hide got flooded.

It got flooded up to about, I guess, 1.6 metres.

It all poured into the hide, filling the whole thing with mud.

Had to give it a good clean out.

Unlike a natural water hole,

ours is designed to keep running all year round,

no matter what the environment throws at it.

We can simply turn on the taps to fill it up,

drawing water from a naturally occurring sustainable source

47 metres underground.

This means Mwiba will be able to keep this water hole going

long into the future.

The rainy season is already bringing in an exciting array of new animals.

Look at this dragonfly here.

Look at that - absolutely fantastic.

Hunting over the water hole.

There are over 3,000 species of dragonfly.

This one, the wandering glider,

migrates a staggering 18,000km from India to Africa...

..further than any other insect.

Bush crickets look similar to grasshoppers,

but they have much longer antennae that can be longer, in fact,

than their whole body.

This common diadem butterfly male is black with white spots.

But the female is mainly orange,

mimicking the toxic monarch butterfly to avoid being eaten.

The place is alive with insects now.

And you know, the water hole has had its times -

it's had the time of elephant and buffalo,

it's had the time of hyena.

Now is the time for insects.

And that's down to the fact that it's rained.

All of the grass is growing.

All of the plants are growing out here.

And that lush salad is a food for herbivores,

not just the big guys, the mammals, for all of the small invertebrates,

all of those caterpillars, grubs and larvae which are out there.

We're only an hour into our first day and this new burst of life

has added four species to our list.

But so far, no mammals have shown up.

Last time we were here, hyenas were taking over the water hole

at night, and we're curious to see

if they're still a dominant force.

But since the rains began, our camp has been invaded

by a new nocturnal species.

I'm all of a flutter, or rather I'm not,

but all of these termites are. These are the alates.

These are the winged adults, the males and the females,

the fertile males, fertile females that have left the nest tonight.

And with the first flush of rains, they will all emerge

from the termite mound at exactly the same time.

And not just one mound - very often all the mounds in that region.

So outside the tent - we're trying to keep as many out as possible -

there could be probably hundreds of thousands, potentially millions

of these insects flying around at the moment.

Why have they done this?

Well, frankly, they've got to mate.

But also, this is a classic case of predator swamping.

Imagine you're an animal here that has a taste for termites.

Well, you could fill your belly,

but you wouldn't be able to eat them all. Some would survive.

You swamp out with your sheer abundance, the appetite

of all of those predators.

The larger females are very fatty.

They've got lots of fat reserves because once they've mated,

they will shed their wings, find a crevice in the ground,

crawl into it, and there

begin to form a new termite colony.

And until it gets going,

they need to live on their fat resources.

They need those to lay the first batch of eggs, of course.

And once they start their colony, the females, the queens,

can be very long-lived.

Some of these ant and termite species can live for up to 45,

maybe even 50 years, but under the ground,

after just one night of flying around in the free air.

What about that? What an existence!

Not for me.

Over the first 24 hours, there's no sign of the hyenas

that were monopolising the water hole last time.

In their absence, the water hole community is reclaiming the site.

Vervet monkeys...

..giraffe.

Impala...

..elephant...

..and olive baboons.

It's great to see them again.

And it's a sign of the role the water hole area

can play in the future...

..even when these animals can find water everywhere.

This is our water hole troop.

Now we've seen these baboons sleeping in the trees at the back.

We know that they're there.

We've caught them a few times on the cameras.

But this is the first time we've seen them in the rainy season.

The baboons have been coming to the water hole

from the very beginning.

It was a vital water source in the dry season...

..and now it provides a great supply of food...

..all on their doorstep.

And to see them quite like this is actually really, really spectacular.

They're just really owning the water hole.

You can see a juvenile, there, just hanging out on its mum's back.

Grass is around 80% water.

So at this time of year, they're getting nutrition

and hydration with every mouthful.

They spend about 50% of their day foraging for food.

If you see the way they're eating, they're stripping the leaves off

and they're eating the shoots and the roots.

By pulling up the grass, eating it and passing it

through their digestive system,

olive baboons act as seed dispersers...

..helping the water hole site to stay green and lush

for the next generation.

Over the next few days, we watch the same visitors that came

in the dry season to drink...

..now come to eat.

Despite there being food and water across Mwiba,

these animals are still returning, and for good reason.

We worked closely with the reserve to create a water hole

that would support many species for years to come.

Specifically choosing to build it in one of the few patches

of open grassland amongst all the acacia woodland.

The site's accessible to lots of local wildlife

and, thanks to the new water hole,

is able to support them all year round.

And now this emerging ecosystem is showing signs

that it will also sustain new life of its own.

It's exciting times down at the water hole here,

because up until this point, all of the animals that have been

coming here have been visitors, but now we've got some residents.

And I'm feeling quite pleased with myself

because I've scooped this out of the water hole.

This is a large diving beetle.

They are ferocious predators.

This is the leopard of the water hole beneath the surface,

in insect terms.

Diving beetles use the damp soil by the edge of the water

to pupate in.

All the churned-up edges of the water hole are a perfect

breeding ground for them.

So if you've got a large predator like this,

you've got to have something in the pool for it to eat.

We've got something. Look at this.

This mass of wriggling black organisms down here

are tadpoles.

Yes, we've had amphibians colonise the pool.

They've clearly come here, bred, laid their eggs in the form

of spawn and they've hatched out into these tadpoles and there

are plenty of them, which is fantastic.

I'm really excited to say that we've got our first

resident birds.

They're not actually at the water side at the moment.

They're out doing what they should be doing,

which is feeding.

This is a pair of Egyptian geese.

They started visiting the water hole a few months ago.

But Egyptian geese tend to stay put in an area

that has a good supply of water.

So with the water hole being topped up regularly,

it looks like they're here to stay.

Their natural habitat is along the Nile

and then south of the Sahara.

But I know what you're thinking, you might have seen them in the UK

because they've naturalised there and they're particularly common

in the east of England.

They're not technically a goose, though.

They are, in fact, a large duck, quite closely related

to our shelduck.

And they're a grazing animal. That's what they're doing,

munching away on all of this fresh grass.

Now, outside the breeding season, they're quite gregarious.

You get them in flocks, but when they come to breed,

you get them in pairs like this.

The male is the one on the left there, with the pink, rosy bill.

And the female's on the right.

When this pair arrived last season, they were quick

to make their presence known.

Since then, they've been regular visitors,

and they've proved they're not to be messed with.

When another goose came to check out the new water hole,

our male made it clear that it wasn't for sharing.

Even the arrival of a martial eagle,

a predator that can take prey as large as an antelope or stork,

didn't put them off.

And neither did hyenas.

It seems this pair want to have our water hole

all to themselves.

And should they breed, they'll make a nest in one

of the thickets here, and then they would hatch their eggs

and lead their ducklings across the lawn and into the water hole,

the security of that water, to keep them safe from ground predators.

And of course, with all of these new species coming here,

that will supplement the diet of those ducklings.

They're dependent on aquatic invertebrates for the first few

weeks of their life.

But what about that?

Our water hole really is becoming a home

for a great range of creatures.

It's from small beginnings, like our water hole,

that aquatic ecosystems can build to support a huge range of life.

20km south is Lake Eyasi.

A water source that's evolved over 65 million years to be

a vital lifeline to one incredibly beautiful species.

Looking down on this lake is extraordinary.

It's like a bizarre abstract painting.

Speckled with these rose spots of...

..the greater and lesser flamingos.

These birds flock to Lake Eyasi in their millions...

..using it as a stop-off point as they migrate to breed further north.

The lake can sustain such vast numbers of flamingos

because it's full of microscopic algae called cyanobacteria -

plants that are poisonous to most animals, but not to them.

And famously, they have that beak which is upside down.

And using their tongue as a pump, they filter vast quantities

of the water to remove all of this food.

And there's another twist.

This is a soda lake.

The water is extremely caustic.

If they really need to, flamingos are one of the only animals

that can drink here, using glands in their head

to filter out the salt, draining it from their nasal cavity.

It's still a difficult environment for these birds.

The alkalinity of the water means that if they get

just one little nick on their leg, it becomes an open sore

and they soon perish.

For a harsh environment,

it's one which is extraordinarily beautiful.

Lake Eyasi shows how much freshwater sources

like our water hole are needed.

When we first designed it with Mwiba, the idea was to make

a reliable water source for as many species as possible.

But earlier in the year, we were worried that it was only

going to be used by one animal...

..spotted hyena.

I've been looking back over the data and it paints a stark picture.

Last time we were here, the hyena dominated the water hole,

and in the end we managed to identify 16 adult individuals.

Now, we've been logging their movements.

They visited the water hole 73 times.

Now, compare that to our situation right now...

..the heart of the rainy season.

We haven't seen a single visit from a hyena.

You go from 73 visits to nothing.

To find out why they're no longer coming to our water hole,

I return to their den site, 2km away.

Frankly, it looks to me as if they've abandoned this den.

It's all overgrown here.

All of the vegetation is standing up,

and if there were a boisterous band of hyenas here,

then this would have all been knocked down.

And look over here.

It's been raining, it's muddy, there's not a single footprint.

And look, there are lots of plants here, grass growing through.

These would have all been knocked down if this was still occupied.

I'm hoping our camera traps

might give me some clues as to why they've left.

A giraffe.

There's a couple of hyenas - there's an adult in the foreground.

There's a cub, another cub behind it.

Oh, look at that, two of my favourite African mammals

in the frame at once - the fantastic crested porcupine

and a young hyena.

And guess who comes off the winner.

Porcupine, of course. Look at that!

A bit more porcupine action here.

You see those quills erected?

The porcupine is clearly agitated.

Now, you might be wondering, why has a porcupine come to a hyena den?

Well, hyenas bring lots of parts of the things that they've been

scavenging back to the den, including plenty of bones,

and porcupines love gnawing bones

because they need all that calcium to produce their spines.

But it's unlikely that a few small porcupines would scare them away.

Oh, my goodness, look at that. Buffalo.

There were a whole herd of buffalo clearly moving through,

trampling over this site.

Maybe this was what put them off.

Maybe it was just the abundance of other animals that drove them away,

and certainly at night, with all of those buffalo,

they wouldn't want their cubs emerging

and the risk of them getting trampled.

I think I know WHY the hyenas have moved dens,

but the question is - where are they now?

We send out several film crews to find them...

..and one of our cameramen spots their new den,

2km from the previous one.

They appear safe and well.

Spotted hyena can have many old den sites spread across the savanna.

It looks like this clan moved their pups to an area

with fewer animals.

In a year, these pups won't be so dependent upon the den.

And they may return to the water hole with their clan.

With no hyena in the vicinity,

the water hole is a safer place for prey once again.

There are over two million impala across Africa.

They time their breeding season with the rains, and their population

spikes by hundreds of thousands.

It's exciting to see this new generation come to the water hole.

Ooh! There we are. The impala have turned up.

And they've brought their young.

Look at that.

It is undeniably cute.

Big ears, big eyes.

Groups of young impala are called creches.

This is the first time we've seen them at the water hole.

So these have been born a few weeks ago. And initially, of course,

they'll be dependent on their mother's milk.

But then when it comes to them moving onto solid food,

they need to time that so that they've got this crop of ripe,

green, highly nutritious, fresh grass.

Looks to me as if this group of impala timed that birth perfectly.

These young impala are likely to be regulars at the water hole.

Patterns of behaviour set now

should mean they'll remember this oasis in the future.

The rains don't trigger the birthing season

for all of our water hole community.

5km away, wildlife cameraman Bob Poole is discovering

this is actually a peak time for mating

amongst many of Mwiba's herbivores.

OK, now watch this female.

It's incredible.

She comes up to the male,

then she rubs her neck against his like that.

It's definitely a sign of affection or interest.

At this time of year, amorous giraffes use their sense of smell

to help identify if a female is ready to mate.

So the male giraffe right now is trying to determine

whether the female in front of him is in the peak of oestrous.

Oestrous cycles in giraffes, like human menstrual periods,

help identify when a female is ready to mate.

They occur every two weeks,

but a female giraffe is only fertile for four days or less

during this time.

She gives off pheromones which he senses through sensors

that are in the top of his lip, there.

Giraffes mate all year round.

But there is research that indicates breeding increases

with periods of high food availability.

All the leaves are so plump right now.

I can see the way that they use the tongue

to strip the leaves off the twig, which is, of course,

loaded with these big thorns.

And everything around here has a thorn on it.

In fact, this place is called Mwiba,

which literally means "thorn" in Swahili.

All of this food means other herbivores like zebra

are also getting ready to mate,

and sometimes competition between stallions can get physical.

Look at this!

There's so much action going on right now. The... the stallion here

is racing around trying to round up the zebra females,

and you can see him racing across in front of us right now.

And now he's coming back to probably his harem right there.

The young males have to struggle for dominance.

He could get kicked out by another stallion.

These are very social animals.

They live in family groups and they have an order,

a pecking order, essentially, just like horses do.

They're constantly having to put each other in their place

so there's a lot of fighting and testing, and all kinds of action

going on all the time, to sort of really work on who's who

in the family and where they sit in terms of the pecking order.

And some have already had their young.

This foal is just four weeks old.

The little foal, to the right,

would be his first foal of this rainy season.

During this time of plenty, the savanna is overflowing

with calories for new mums to produce milk.

And when babies are ready,

there are swathes of grass waiting to be grazed.

The water hole is getting busier each day with insects...

..and we spot two interesting new species for our list.

Hoverflies are harmless, but they mimic stinging bees

and wasps to put off predators.

Leaf roller moths pupate from inside a rolled-up leaf,

sealed shut with the caterpillar's silk.

All the insects are attracting

more new bird species,

including...

a red-necked Francolin,

a relative of the pheasant.

It's a wary bird,

often staying hidden from predators in deep cover

and only coming out in the open to feed.

A three-banded plover, named after the black and white bands

on its chest.

They hunt by sight for insects, worms

and other invertebrates.

And we have another new resident bird,

taking our species list to nearly 100.

This has made my day. When we were here last time, there were a pair

of lesser striped swallows

prospecting to make a nest inside our hide.

Earlier in the dry season,

our cameras captured the moment when these swallows were first choosing

where to build their nest.

These swallows typically nest under bridges for protection

and the roof of our hide offers a great alternative.

The water hole has also provided perfect nest-building materials.

Both birds use mud for construction, and you can see this one's beak full

of mud, deciding where to start plastering.

I really hoped they would move in here.

And look, they have. And it's a beautiful structure, as well.

Now, it's slightly different than a typical barn swallow's nest

that we see, which is an open cup.

Here, they close the cup and then make that neat little tunnel there -

I suppose to try and keep predators out, maybe things like snakes.

It's a fantastic construction,

welded into the corner of the building there.

A little work of art.

So I'm really pleased that they've used our hide

to make their home.

I'm pretty certain that we've got young in here.

I've been watching the two adults hunting outside together,

and then going in one at a time, delivering food.

Feeding chicks is a full-time job for both parents.

We're seeing them bring back food every 20 minutes.

If they were still incubating or brooding, typically

one's off the nest whilst the other one's sat on it.

But because they're both active away from the nest,

I reckon there's young up there.

So we've done a great job for these swallows here.

We provided the water and in turn the food, and then we provided

the structure for them to place their nest.

It's good. I like that.

And, even better -

because swallows return to the same nest site year after year,

our hide could well be their home long into the future.

And the water hole is going to provide the swallow chicks

with all the food they need

because both pools are teeming with mosquitoes.

Mosquitoes lay their eggs on water.

Each female can produce up to 500

in her one-month lifespan.

Many mosquito species stay within a few hundred metres

of where they're hatched, so it's likely they'll be

a regular feature at the water hole every rainy season...

..providing a reliable food source to birds like these swallows.

Insects and birds are important foundations for a healthy ecosystem,

but we're working closely with the Mwiba guides to make sure

the water hole can also attract and sustain Africa's megafauna...

..the most important of these being elephant.

ELEPHANTS MAKE RUMBLING SOUND

Elephants are keystone species.

They help disperse seeds, and also create pathways to water holes

as they walk to them.

We've had over 100 individuals,

and one extraordinary half-trunked

elephant used this lifeline over the past six months.

Mwiba guide Eugene Raymond is confident that these elephant

populations are likely to keep coming back to the water hole.

It's unbelievable that they have this ability

to remember places, areas,

and with experience, they're able to find.

An incredible ability also to find water.

Now, we've seen this animal at the water hole here, and we know

they've got phenomenal memories,

it's going to be interesting to see whether it remembers the water hole

come the dry season - when it really needs that water.

Research shows that elephants can remember the locations of food

and water for up to a decade,

even when seasonal and environmental changes alter the landscape.

A permanent, refillable water hole like ours

should be an elephant oasis for many years to come.

And Eugene has been pleased to see so many herds coming

to the water hole, because it's the matriarchs

that lead their families and remember where to go.

This mama elephant, or Tambo we call her,

who will be able to remember these places and come back into the same.

And that's why the herd put trust in them.

And they would normally try pass this on into the next generation

by just, you know, testing as individuals the ability to navigate

the rest of the group members and remember these places.

This comes with experience. Age.

It's a bit like you going shopping with your grandmother, isn't it?

It's true, yeah. She knows where the best shops are. Exactly!

Where to get the best deals at the right time of year.

Absolutely true. Yeah.

Elephants can eat up to 250kg of foliage,

and drink up to 200 litres of water every day.

They're one of the heaviest users of the water hole...

..which is why it's so exciting that Eugene and the Mwiba team

will keep refilling it in the future.

We've had word of a new species in the area that could drink

more than all our Mwiba elephants combined.

The world-famous wildebeest migration has been making its

epic journey 400km south from Kenya,

and it's now 10km away from our water hole.

Together, these animals can drink

up to 13.5 million litres of water

and eat up to four million kilograms of grass in a single day.

So that's where we are right now, that blue dot.

And you can see they're heading right towards us.

To get an idea of the impact they'll have on the area,

and our water hole community, I'm taking to the air.

This is one of the most astonishing sights that I've ever seen.

We're looking down on the world's largest mammal migration.

Just sensational.

There are thousands of wildebeest beneath me in a long line

stretching across the savanna. A group of perhaps 1.5 million

of these animals that are constantly on the move

in this Serengeti ecosystem.

They make the journey, which lasts a full year and covers 1,000 miles,

clockwise from here, all the way up through the Serengeti

to the Maasai Mara and then back down again.

Right now, they're at the southernmost part of that cycle,

on the edge of Mwiba reserve.

While I track the migration from above...

..Ella is getting a closer view on the ground.

They're now 8km north of the water hole.

They undertake this crazy journey because of this,

because they're after these really nutritious grasses.

Essentially, they're storm chasers.

They're chasing the rains which feed these grasses.

If you look at their bodies, they have these really significant

incisor rows and loose lips,

and that's to help them rapidly eat that grass.

They consume up to 16kg a day.

Look at how much they're moving in unison.

They're moving in formation, and yet there's no clear leaders.

It's the most fascinating example of swarm mentality in mammals.

Because wildebeest have no leader,

the migrating herd often splits into smaller groups

that circle the main mega-herd.

Joining them are thousands of zebra.

They graze in harmony with the wildebeest because they

eat different parts of the same type of grass.

From above, I can clearly see how this huge number of animals

might affect life at our water hole.

Their movement has an extraordinary impact on this ecosystem.

Firstly, directly - that grazing pressure is preventing

the regeneration of trees. It's keeping this as open savanna.

Also, the impact that they have on the predators.

This is, of course, an enormous amount of meat on the move.

Many animals will take advantage of that.

Lions will simply stay in their territories

and eagerly await the arrival of the wildebeest.

Ditto the crocodiles that are stopped in those rivers

which they have to cross en route.

Then lastly, there are predators that will go out for the day,

follow the wildebeest,

but then go back to their dens in the evening, or in the morning -

depending whether they're diurnal or nocturnal.

Things like wild dogs and those spotted hyenas.

On average, the migration travels up to 5km a day.

It looks like this year,

they're going to skirt around the water hole site,

so the natural order of our ecosystem remains unchanged for now.

But next time, it could be a different story.

The water hole will always attract new seasonal visitors.

But in the six months since being built, it's becoming

a permanent home for some.

And it's our filming hide, perched in the middle of the water,

that seems to be the location of choice.

You may not be, but I'm very pleased to see

that these animals have taken up residence in our hide.

This is a paper wasp.

It's one of a number of species

known as Belonogaster.

And they're very similar to the social wasp

that we have in the UK - in terms of their behaviour,

not their physical appearance.

You can see it's got a much narrower, longer waist there

towards the end of the abdomen,

and those beautiful red wings.

This is a queen and that nest has just about got started.

So she's arrived, chewed up some paper on a tree out here,

and she's made that tiny little petiole - that strong piece

of fabric here, which is going to support the whole nest

and it's going to grow considerably larger than this.

Then she's made a couple of cells,

and into those she's laid some eggs.

And at the moment, she's having to fly out and hunt

to feed those grubs, which are just nestling in there.

Probably caterpillars is going to be the main source of food

that she's looking for. Something soft and easy to chew.

And she'll come back, and then she'll scrape the edge of the comb,

and the larvae will come up and she'll delicately feed them.

She's a bit mobile at the moment.

You can see her moving around there.

And you can see one of the grubs there

with its head capsule just coming out of the cell.

Maybe it's a little bit hungry.

when they emerge, those workers divide themselves into castes.

They do different jobs.

So, some will be guards.

Others are foragers, and they will go out hunting

for those caterpillars to bring back.

Meaning that the fertile queen, the most valuable

part of this colony, will be able to remain in the safety and security

of our hide on the nest.

People sometimes say, "What are wasps for?"

My reply is always simple, "What are you for?"

You shouldn't misjudge wasps just because they sting.

They're fascinating insects and an integral part of the ecology here.

Now, down by the water hole at the moment, we've got this lush,

green carpet of grass being munched by loads of herbivores,

and they're not all big animals like impala.

A lot of them are small things, like the caterpillars.

And if these guys weren't controlling those caterpillar

populations, then the whole place would be defoliated.

The ecology would collapse.

You need everything in place to maintain that balance of nature,

to keep that beautiful, dynamic harmony working.

And that's why you need wasps.

Wasps are cool.

The paper wasp brings our list up to 101.

The number and variety of species is impressive,

considering the water hole is only six months old.

But how does it compare to a long-established,

naturally occurring freshwater source?

Mwiba is part of one of the oldest ecosystems on Earth...

..the Serengeti.

And 7km from our water hole is Sele Springs.

It's hundreds of years old, but almost disappeared

in the dry season.

Thanks to the recent rains, it's full again.

To find out how this ancient spring

contrasts to our fledgling water hole,

we've brought in Dr Meredith Palmer.

She's been studying the Serengeti ecosystem for over a decade

and has been using camera traps at Sele to gather data

over the past six months.

So here, if we're focusing on the mammal species,

we can see that Sele Springs would be a very similar number

of animals showing up.

Incredibly, our new water hole is sustaining as many

species as Sele.

And there are some animals that are only coming

to our water hole.

We're getting more mongoose...

..porcupine, rabbits, spring hares,

a lot more monkeys here.

At our water hole, on the other hand, we're getting servals.

We have things like waterbuck...

..kudu.

Dr Palmer's research shows that wildlife is also behaving

differently at each site.

Despite it being new in the landscape, many animals

are more comfortable drinking at our water hole than at Sele.

So, impalas are spending far more time there than they are at Sele.

We can see the same with the giraffe.

At our water hole, impala stay for around half an hour each visit.

That's twice the length of time that they spend at Sele Springs.

And that's also the case for zebra and giraffe.

Any theories on why that might be?

It could be a safety issue.

Our water hole is a little bit more open,

you can see the predators coming.

They might feel safer to stay longer.

By working with Mwiba to build our water hole in an open area,

we've made a safer place for many herbivores.

Predators have fewer chances to hide,

and as a result, a lot of species seem to take their time

at this brand-new water source.

And the more wildlife feel secure,

the more likely it will return in the future.

Our water hole's the new kid on the block

and it's still done pretty well.

I mean, comparatively, we're looking at similar numbers

of mammal species, that's... That's really impressive.

Yeah, I think it's amazing how quickly the community assemble

at our water hole, how many animals we got

and how soon they showed up.

We're seeing the same forces shape animal behaviour

at our water hole and other water holes like this.

And even though it's still an experiment in progress,

the community is still jostling and assembling

and becoming a water hole.

Having the opportunity to look through all this data,

and it's such a fine scale, has just been really fascinating.

Mwiba are planning to keep studying the water hole in the future

to reveal the long-term impacts of water availability

on African wildlife.

And their ecosystem manager, Mark Ghaui, is excited

by the potential of having this constant water source

in the reserve.

This started off as a little experiment, but it's been

a remarkable success, hasn't it?

Yes, six months has gone really quickly and it's amazing

to see and feel how much part of the landscape it is.

I think to be able to guarantee water will just be, without a doubt,

beneficial for these populations.

Water has been in such short supply in Mwiba

that conflict has been increasing

between wildlife and human populations...

..who often use the same natural water sources.

Mark hopes that the new water hole might be a possible solution

and has been keeping an eye on incidents in the area

over the past six months.

In terms of human-wildlife conflict,

do you think that this has played any small role in reducing

that in this local area?

We are close to the boundary and also close to watering points

that communities use and I think to have a water source here

that they can access without leaving the reserve

and troubling those communities will definitely...

I think we'll definitely see a reduction

in human-wildlife conflict as a result.

Conflict is a growing problem across Tanzania, where there are no fences

between wildlife reserves and villages.

Many tribes are herders, keeping thirsty animals like cows

that need to drink up to 100 litres of water a day.

There's been an explosion in cattle over the past three decades.

Now, there were approximately 30 million cows

across the country.

It's putting a huge strain on supplies.

And when water runs low, people have little choice

but to violently protect that water.

Last year on the outskirts of Mwiba, there was one human fatality

and countless altercations as humans and wildlife

fought over food and water.

But in the past six months, there have been no reported incidents

near Mwiba's park boundary...

..thanks, in part, to our water hole.

What about the long term legacy, then?

I think it's going to be a big part of our landscape going forward.

I think, yeah, from our perspective, it's just getting started.

And, yeah, it's been wonderful to see how animals have fixed

their lives and their routines around it, how they've engaged

with it and I think we'll be seeing that

for many, many years to come here.

to our species list.

The hoopoe is named after its distinctive call.

ECHOING WHOOP

The woodland kingfisher is one of the many kingfishers

that don't just eat fish,

but also hunt insects, frogs and snakes.

The rufous-tailed weaver is a monogamous bird that's only

found here in East Africa and nowhere else in the world.

We've been recording a vast array of animals over the last six months.

And I'm digging into the data to find out what this unique

experiment has revealed about how wildlife interacts

at a water hole.

We've had our cameras on for over 1,400 hours

during the six-month period.

We've got data coming out of our ears and we can see our

final figures now.

We've recorded 105 species visiting our water hole...

..including 26 different mammals.

GRUNTING, SQUAWKING AND ROARING

If we look at them according to size, it's the mega-herbivores,

elephant, buffalo and giraffe, that came in the biggest numbers.

But they didn't spend the most time here.

Clocking up an impressive 19 hours...

..the impala stayed longer than anyone else...

..enjoying the safety provided by the open landscape

around our water hole.

Surprisingly, though, they weren't the most frequent visitor.

It was the hyenas that came to the water hole

more than any other species...

..making a total of 121 separate visits.

Now, this personally is actually really surprising to me.

I wouldn't have expected that a carnivore

would have been the most frequent mammal to the water hole...

..but they were.

We always assumed water-dependent herbivores would visit

the water hole the most.

But it's actually good news that hyenas came so frequently.

They're known as the health police by scientists,

because they can eat animals that have died from diseases

that are deadly to other species.

Their stomach acid and immune system is so strong,

they're one of the few animals that can digest anthrax and survive.

If they return, they'll help keep this new ecosystem in balance.

This has been an extraordinary venture.

We've had a rare chance to see a whole community of wildlife

taking shape around a water hole that six months ago

just didn't exist.

And the great thing is...

..it's here to stay.

Our water hole will benefit future generations of wildlife

and also the people it shares the landscape with.

When we arrived here, this little corner of Africa

was just a dusty piece of savanna.

But over the last six months, we've seen

a remarkable transformation.

It's undeniable - this experiment has become a huge success.

We did wonder if the animals would come, and they did.

And they are still coming.

You know the best thing?

We've made something that a whole bunch

of animals now call home, and that puts a smile on my face

and makes me feel pretty good.