(THEME MUSIC)
Tanzania is a relatively small country in Africa
but it has some of the largest herds of wild animals on the planet.
And these herds are easy to encounter as they sweep across
the vast savanna grasslands.
Tanzania sits just south of the equator
so there's no real winter or summer, just wet and dry seasons.
The rains come twice a year,
a short burst from October to December,
and a longer, stronger wet season from March to June.
Ngorongoro crater, an ancient volcanic caldera,
sits at the heart of Tanzania's wildlife extravaganza.
It presents a striking landscape, created by a cataclysmic explosion
that occurred over 3 million years ago.
The original volcano would have been as high as Kilimanjaro,
the loftiest mountain in Africa.
But after it erupted, it collapsed,
leaving behind this remarkable sanctuary
known locally as 'the Garden of Eden.'
The crater sinks to a depth of 2000 feet,
creating a natural enclosure.
A giant bowl containing an alphabet soup of Africa's wild animals,
from antelopes right through to zebras.
In all, 25,000 large animals
and at least 100,000 smaller ones
coexist here in ecological harmony.
Ngorongoro crater is the perfect place
for spotting what safari guides call 'the big five' -
Africa's largest and most charismatic grassland animals.
The lion.
The leopard.
The elephant.
The rhinoceros.
And the Cape buffalo.
Lions are the only big cat to live in social groups.
A pride of lions is an extended family
with about 10 females and their young.
As the cubs grow, young females will stay with the pride
but by three years of age, young males leave the group
to find a pride of their own.
Becoming part of a new pride is no easy feat,
for the dominant male in the group
will fiercely defend his territory from newcomers.
He'll mark the boundaries with urine, roar menacingly
and chase off any intruders.
Not an easy job as a single territory can be over 250 square kilometres.
Once a young male is sexually mature, he is ready to challenge
the dominant male for the right to take over his pride.
Typically, tenure of a pride lasts around two to three years,
giving the dominant male the exclusive right
to every female in his harem.
Female lions do almost all the hunting.
Many of their prey animals can run faster and further,
so to effect a kill, lions need to work as a team.
They'll take their time stalking their prey.
Often, the pride will split up, so the escaping prey
runs straight into an ambush.
There is a strict pecking order when it comes to eating,
and so cubs have to make do with the leftovers.
After a good meal, lions may sleep for up to 20 hours.
A rite of passage for groups of young Masai men
has always involved the hunting and killing of a lion.
But here in Ngorongoro, times have well and truly changed.
Now, these Masai warriors are being employed by local experts
to help protect the lions using science and traditional knowledge
to manage and monitor these magnificent animals.
While lions have evolved to be social,
leopards are the loners of the African big cat world.
They spend much of their time hanging around in trees
and are mainly nocturnal.
During the day, the dappled light in the branches
allows the leopard with its spots to blend in.
Camouflage gives the leopard the upperhand when it comes to hunting.
Of the big five in Ngorongoro,
they are definitely the hardest to encounter,
requiring a mix of patients and luck,
but the payoff is well worth the effort.
Leopards are incredibly strong with powerful jaws.
A single animal is able to haul a large carcass
right up into the tree so it can eat in peace,
a handy trick as prowling hyenas and lions
would otherwise help themselves to a share of the kill.
The athletic prowess of the leopard doesn't stop at tree-climbing
and weightlifting.
They are excellent swimmers, fast runners
and can jump up to 3 metres in the air.
The Olympic pentathletes of the grasslands.
A single leopard will occupy a territory
of up to 75 square kilometres.
One male will choose a territory that overlaps
with a few female territories.
In this way, he has a range of choices
when it comes to mating season.
The largest of Ngorongoro's big five is the largest animal on land,
the African elephant.
These awe-inspiring creatures live in herds of up to 100.
They are sociable animals that spend a great deal of time
with their families roaming the grasslands,
looking for water and food.
And it goes without saying that an animal of this size
needs to eat quite a lot.
One adult will easily consume over 300 kilos of grass,
leaves and bark in a day.
So a herd like this needs an enormous area of land to survive.
Many of the herds at Ngorongoro choose to live on the crater rim
where the air is cooler and the opportunity to graze
expands beyond the old volcano's boundaries.
The other great grey grass eater in Ngorongoro
is one of the most endangered big animals in Africa - the rhinoceros.
There are two spaces of rhino in Africa, the black rhino
and the white rhino.
Confusingly, these rhinos are neither black nor white,
rather a very similar shade of grey.
Rhinos are short-sighted so there's a good chance of spotting them
in Ngorongoro before they spot you.
Like many animals with poor sight, rhinos compensate
with excellent senses of smell and hearing.
Despite their bulk and relatively short legs,
rhinos are impressive runners.
They can easily get to speeds of 50 kilometres an hour.
Both species are endangered due to the continued demand for rhino horn.
It is mistakenly believed to be an aphrodisiac,
fetching around US $60,000 per kilogram on the black market.
Rangers who have dedicated their lives to ensuring the survival
of rhinos in the wild are often forced to take
somewhat drastic measures to thwart the efforts of poachers.
This can include removing or dying a rhino's horn
so it's no longer of value to the poachers.
When conservationists became aware of the dwindling numbers of rhinos
in the wild, they moved a number of individuals to Australia.
They are thriving now in open range style zoos, breeding generations
that could, in time, be released back into the wilds of Africa.
The final member of the big five in Ngorongoro is the Cape buffalo.
They won't hesitate to take on and slay a lion.
In Ngorongoro, in a good year, a single buffalo herd
can contain over 500 animals.
Those lethal horns are the reason these animals are so well respected
by even the most skilled predators.
Both female and male buffalo have horns.
They grow from central boss on the forehead
which acts like a powerful battering ram.
There is one animal however that is safe in the Cape buffalo's realm.
The Ox Pecker.
This elegant bird will happily ride around
on the back of a buffalo all day,
eating ticks, mites and other parasites
that would otherwise irritate the buffalo.
The Cape buffalo is the only member of the big five
that is not endangered, but they do need huge amounts of food
and a good 10 and a half gallons of water a day to survive.
Fortunately, in Ngorongoro crater, there seems to be enough
of both to go around.
North America's version of the Cape buffalo is the mighty bison.
They once roamed across the grasslands here in massive herds,
migrating between their summer and winter pastures.
But hunting on an unprecedented scale during the 19th-century
bought them to the brink of extinction.
Some 50 million bison were killed, reducing their numbers
to just a few hundred individuals.
Here in Yellowstone, the oldest national park in the world,
bison are well protected so the numbers have slowly rebounded
in step with other herds across the country.
There are now half a million bison living in reserves
and commercial ranches.
The bison is the heaviest land mammal in North America
and seriously impressive to encounter in the wild.
Full grown males can be over 2 metres tall at the shoulder
and weigh over a ton.
Outside the migration and mating seasons,
these animals prefer to live in smaller groups,
mostly females and their young with a dominant male.
During the summer mating season, the groups come together,
and males do what so many herding males do -
fight for supremacy.
Fortunately, a lot of this is sabre rattling,
and despite the animals' formidable power,
injuries are not common.
Competing males also make earthshattering bellows,
and surprisingly, recent data from scientists
suggest that the females appear to favour males with a quieter bellow.
These huge animals spend a lot of time grazing and chewing their cud.
Grass and herbs are top of the list of food favourites
but shrubs and twigs also fit the bill.
The cow bird is North America's version of the African Ox Pecker
and they've become the bison's regular companions.
Insects and parasites are commonplace on the hide of the bison
so the cow bird receives regular sustenance
in return for the free cleaning service.
On May 9, 2016, President Barack Obama
signed the National Bison Legacy Act, formally recognising the bison
as the official national mammal of the United States.
A fitting tribute to one of the most impressive grassland animals
in the world.
Another amazing animal to encounter on the prairies of North America
is the pronghorn, the second fastest animal on four legs.
Having survived the last ice age, the pronghorn has not changed
its behaviour, habits or good looks
since it first raced through the great South West
some 30,000 years ago.
Pronghorns are not technically antelopes
as they have quite a different horn structure,
but they fill the same ecological niche.
These impressive animals can reach speeds
of over 80 kilometres an hour and have exceptional endurance.
These herds migrate around 300 miles every year in order to survive,
one of the longest migrations by land animals in the world.
The main migration south takes place in the autumn
when the pronghorn's need to move out of the grand Teton Mountains
as the snow approaches.
They spend the winter in Wyoming before following
the retreating snowline north to their mountain grasslands
in the spring in time to breed.
They are incredible to encounter during the migration season
as they travel in large herds.
Pronghorns are a well-equipped for running.
They have a large windpipe, heart and lungs.
And they can outrun all of America's key predators including wolves,
bobcats and cougars.
Fortunately for the pronghorn, the only animal
it couldn't possibly outrun lives on another continent - the cheetah.
The fastest land animal on the planet lives in sub-Saharan Africa.
There are only about 10,000 left in the wild,
doing their best to outrun extinction,
and here in Namibia, they appear to be winning
the race of their lives.
A key stronghold of the cheetah is Etosha National Park
in Namibia's north.
The landscape here is unbelievably harsh, but nonetheless,
it helps Namibia lay claim to the title 'cheetah capital of the world.'
In the centre of Etosha,
there's an ancient salt pan which, during the rainy season,
draws four-legged and two-legged visitors like a magnet.
Including many of the nation's cheetahs.
With a top speed of 100 kilometres per hour,
cheetahs can outrun any animal on earth.
But the first stage of any hunt begins with stalking.
Cheetahs have keen eyesight and excellent camouflage,
so they aim to get as close to the prey as possible without being seen.
Then, the pursuit begins, accelerating faster
than a sports car, it takes just three seconds for a cheetah
to reach its top speed, and when it does, it's virtually flying.
Their long tails act like rudders, allowing the animals
to make sudden changes of direction, and their claws do not retract
when they run, rather, they act like running spikes
when their feet hit the hard ground.
Cheetah hunts result in a successful kill over 50% of the time,
a much better success rate than leopards or lions.
Cheetahs are smaller than the other big cats
so they prey on comparatively small animals -
gazelles, hares and the young calves of wildebeest.
Outside the mating season, cheetahs are solitary animals.
Females look after their cups alone, spending two years
providing for them, playing with them,
and teaching them all they need to know
about surviving in the grasslands of Africa.
Camouflage is a fundamental necessity for many animals
trying to stay out of harm's way on Africa's savannas.
But one gentle giant with very little chance of ever staying out of sight
and off the Safari radar is the giraffe,
the tallest animal in the world.
A full grown bull can be five and a half metres tall.
The fact that giraffes can reach into the boughs of large acacia trees
means they are able to live amicably alongside other herbivores
for there's no need to compete for food.
When it comes to eating, giraffes are uniquely equipped.
First there's that unbelievable tongue,
up to 45cm long and amazingly agile,
enabling the giraffe to pluck out the most tender shoots.
Giraffe tongues need to be tough as well,
for Africa's acacias are covered in thorns.
Giraffes have seven vertebrae in their necks, just like humans,
and indeed most other mammals.
But there's are linked together with ball and socket joints
which give them a great deal more flexibility.
The joint between the neck and skull allows the giraffe
to extend its head at an almost 90 degree angle to the ground.
Male giraffes participate in a ritualised fight called necking.
Their reinforced skulls can normally take the impact of these blows
but giraffes do occasionally knock themselves unconscious
during these fights.
The hornlike nobbles on the giraffe's head
are known as ossicones.
They are not true horns but hardened cartilage covered in skin
and sometimes a small tuft of hair.
Both sexes have them from birth although they lie flat
for the first few months of life.
Up until recently, zoologists believed there were only two species
of giraffe in Africa, but recent DNA tests have pointed
to at least five different species,
each living in a geographically distinct area of the continent.
Just like human fingerprints, each giraffe has a unique pattern
so scientists can easily identify individuals.
Giraffes are already exceptionally tall at birth.
Most babies are over two metres, so they can immediately reach
to suckle their mothers.
Giraffes play a significant role in maintaining the health
of the grassland trees.
Their browsing technique encourages fresh plant growth
and they distribute seeds far and wide via their dung.
In dry places like the Kenyan savanna,
giraffes also need to drink
a lot of water, not the easiest manoeuvre to effect
when you have such a long neck and spindly legs.
Any lesser animal would surely faint.
Fortunately, the giraffe's blood pressure is twice as high as humans,
and their hefty, hard-working hearts beat almost twice as fast.
So they have the means to prevent themselves from passing out
when they move their heads from down low to up high and vice versa.
With all that pressure pushing down on their splayed legs,
it's a wonder the blood vessels in them don't explode.
But giraffes' limbs are wrapped in tough membranes
which compress their veins and arteries
in much the same way as a g-suit works for a fighter pilot.
In fact, scientists from NASA have studied this particular aspect
of the giraffes' physiology and used their findings
to perfect the design of their astronauts' space suits.
It's quite remarkable to think that this gentle grassland animal
is now contributing to exploration beyond the bounds
of the planet we share,
perhaps enabling humans of the future to have close encounters
of a very different kind.
There's really no denying the fact that parts of Australia
look like Mars and that many animals living on this continent
could pass themselves off as aliens.
But two of the nation's most abundant grassland animals
are indisputably Australian, and recognised as such the world over.
Indeed, they even take pride of place on the country's coat of arms.
The kangaroo.
And the emu.
The emu, with its long legs and long neck
is Australia's tallest native bird.
They can reach nearly two metres in height when standing erect.
They can't fly but can run at speeds of 50 kilometres an hour.
Emus are good sprinters but they're also built for endurance.
They can roam huge distances in search of food,
sometimes covering 25 kilometres in a day.
Food supplies in the Australian outback can be unpredictable at best
so the ability to move to other distant feeding grounds
is essential for survival.
The parenting patterns of the emu are also quite unusual.
Male and female pairs remain together for the first five months
of their breeding cycle.
But the male will then take full responsibility
for hatching and caring for their young.
Kangaroo joeys are raised entirely by their mothers.
There are nearly 70 different species of kangaroo
in Australia, filling every niche on the continent,
but most are built for the wide open spaces of the outback,
Australia's version of the globe's great grasslands.
Like most Australian mammals, kangaroos are marsupials.
They are known among scientists as macropods,
meaning large feet, and as a group,
include wallabies, pademelons and bettongs.
They come in an incredible variety of shapes and sizes,
from the rabbit sized potoroo, to the man-sized big red.
They all have strong oversized hindlegs and tails,
and the ability to bound at high speed using long, graceful leaps.
Some species are extremely rare and restricted to small areas,
but the most commonly seen kangaroo is the eastern grey.
These soft featured animals can be found along the eastern third
of Australia, between the coast and the inland deserts.
Like many kangaroos, eastern greys are social animals
living in groups known as mobs.
Each mob is dominated by an alpha male
with several adult females and their joeys
at various stages of development.
Female kangaroos can be looking after three joeys at once.
The oldest will have just left the pouch and be learning
to fend for itself, nibbling on young shoots
but staying close to its mother.
A younger joey will still be developing inside the pouch,
and a third will be in the embryonic stage of its development,
in a state of suspended growth
scientists called diapause.
As soon as the middle joey is old enough to leave the pouch,
a chemical signal triggers the embryo to grow.
Eastern greys are mainly nocturnal, preferring to rest during the heat
of the day and coming out to graze at dusk.
Many Australians believe the kangaroo and emu
feature on the nation's emblem because neither animal
can walk backwards, symbolising the country's highest aspirations,
always moving in a forward direction.
There are actually quite a few countries
that feature grassland animals in their state emblems
but South Africa's is something of a standout.
In a country bursting at the seams with regal options such as lions,
leopards, and elephants, South Africa has chosen
the enigmatic secretary bird to crown its national coat of arms.
Supposedly the secretary bird was so named
because it bore a striking resemblance to the male secretaries
of the 1800s, with goose quill pens tucked behind their ears,
grey tail coats and dark, knee-length pants.
Preferring to walk rather than fly, this large bird of prey
can cover 30 kilometres in a day searching for food.
They are well known for their ability to catch and kill snakes
but will also eat small mammals, reptiles and large insects.
Despatching of prey either involves a swift strike with the bill
or a not so soft shoe shuffle,
stomping on a potential meal to either knock it unconscious
or kill it.
Secretary birds are widespread throughout Africa
south of the Sahara and a key species
on every birdwatcher's wish list.
They're easily encountered in Sabi Sands, a game reserve
that borders Kruger, one of the largest national parks in the world.
There are no fences between the two parks so all the animals
are free to range between the two.
White rhino, elephants, hippo, lions and the world's largest bird,
the ostrich.
This sublime landscape of deep forests and subtropical grasslands
has undergone a miraculous transformation.
It used to be the royal hunting ground for Nepal's rulers
and their guests.
Big game here included the Bengal tiger, the gharial crocodile
and the largest rhino species on the planet,
the greater one horned rhino.
These huge rhinoceros once roamed the entire northern part
of the Indian subcontinent, but by 1975,
they were facing extinction.
Only 600 remained in the wild.
Conservation efforts since then have turned
the greater one horned rhinos' fortunes around,
increasing the numbers more than sixfold,
with Chitwan boasting the second largest population
of this species in the world.
Chitwan is now a World Heritage site and with three decades
of successful wildlife management under its belt,
the place is positively booming.
Elephants rather than Safari Jeeps are used here for transport,
carrying those who seek to encounter these amazing animals at close range.
The greater one horned rhino has a single black horn
which can grow to over half a metre in length.
It also has distinctive folds in its skin which give the impression
of armour plating.
The skin of a greater one horned rhino can be up to 4cm thick.
Add another 2-5cm of subcutaneous fat and you're looking at
one very thick skinned animal.
All that fat seems strange for a mammal living in a hot climate
but it is well supplied with blood which helps the rhino
to regulate its body temperature.
One horned rhinos feed on a wide variety of plants.
Grasses, fruit, leaves and branches are all on the menu.
Most of these rhinos live a solitary life when they are not mating
or breeding.
Each male has a defined territory which changes with the seasons
and according to food availability.
But he will fight to the death to defend it.
Although they are short-sighted, these rhinos have an excellent sense
of smell and good hearing.
They communicate using at least 12 different sounds
including snorts, honks and roars.
Sighting just one individual of a species that has so successfully
bounced back from the brink is exhilarating.
But many would argue that quantity trumps quality
when it comes to animal encounters.
And on that front, the Serengeti doesn't disappoint.
During May and June when the annual migration is in full swing,
the Serengeti is awash with wildlife.
This event is widely regarded as the greatest wildlife spectacle on earth.
Great waves of zebra, wildebeest and gazelle are on the hoof,
moving north from their grazing lands in Tanzania to Kenya.
The monsoon in the south is long over
and the grasslands will soon dry out.
The escarpments up north in the Masai Mara
are catching the last of the rains
so this is where the grazing animals must head.
Around 2 million animals move through the Serengeti,
marching towards greener pastures.
Most of them are wildebeest.
Wildebeest are the major food source for many of the predators
of the African grasslands, but by gathering in enormous herds
and following the food, these stoic animals can keep their numbers high.
Hundreds of thousands of zebra also join the pilgrimage.
Those charismatic stripes do a whole range of things
to keep the zebra functioning happily.
They break up the outline of each zebra's body
so predators cannot spot them in the long grass.
As a herd, they create a mesmerising pattern so it's almost impossible
for hunting lions or hyenas to target an individual.
Scientists now believe the stripes serve a third function.
These open plains can reach temperatures of 30 degrees Celsius
and there's little shade from the equatorial sun.
The alternating black-and-white stripes absorb heat
at different rates.
This probably sets up a microclimate of air currents on each zebra
which keeps the animal cool.
As the migration progresses, the most dangerous challenge
of the journey comes closer.
The crossing of the Mara River.
The steep, unstable riverbanks, and deep and fast flowing water
are difficult enough but that is just the beginning.
Many hungry carnivores are lying in wait.
The banks of the river hide hungry leopards and lions
on the lookout for strugglers.
They know the river crossing will be too much for some,
but the greatest danger of all lies just below the surface
of the mighty waters.
Nile crocodiles, enormous, strong and startlingly fast.
But the hungry herds are driven by the promise of fresh grazing
on the other side of the river.
They have no choice but to take their chances.
This is survival of the fittest at its most brutal.
Getting across the Mara alive is a numbers game.
Of the thousands of animals crossing, less than one percent will be killed.
But there's still one more obstacle before safety is reached.
At many crossing points, the banks of the Mara can be high,
steep and unstable.
Getting out of the river is as dangerous as getting across it.
In 2007, 10,000 wildebeest drowned when the far bank
was just too steep to climb.
Once clear of the river, the animals are in the Masai Mara reserve.
There's plenty of grazing and time to recover before making
the return journey in six months time.
This great migration is one of the ultimate wildlife experiences
in the world, and with luck on your side, you'll have a front row seat
to a truly breathtaking animal encounter.
From the prairies of North America,
to outback Australia and beyond...
..grasslands offer a wealth of opportunity to get up close
to the world's greatest herbivores.
And the predators that relentlessly pursue them.
To witness the drama playing out in these theatres of life
is a privilege indeed.
And a reminder of just how fortunate we are to share our planet
with a cast of thousands.
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