Australia,
A vast country of breathtaking natural beauty...
Teeming with extraordinary and iconic animals.
Meet the kangaroos.
With their long forelegs...
..Distinctive bouncing gait...
..And babies carried in pouches,
They are the most successful and sociable
Of the species known as marsupials.
These kangaroos, called eastern greys,
Populate the woodland, pasture and forests
Of the eastern side of australia.
And their lives are full of surprises...
..Petty squabbles
And big boy brawls,
Companionship and social climbing,
Patient parenting...
And the bounciest babies of all.
This is the secret life of the kangaroo.
It's dawn in sundown national park,
A 61-square-mile area of woodland and open pasture
On the border of queensland and new south wales, australia.
Eastern grey kangaroo enid and her joey ella
Are preparing to leave the forest where they've spent the night.
They've been named by researchers
Who are documenting the lives and social behavior
Of the 300 kangaroos living here.
Ella is an at-foot joey - no longer in her mother's pouch
But still dependent on her mom.
Out on the pasture where they feed,
Another joey josie is taking milk from her mother julia.
As marsupials, kangaroos have pouches with mammary glands,
Where they raise their young.
Josie will have spent 9 months in her mom's pouch
Before starting to spend time on the ground.
She'll gradually start to forage,
But will also still feed from her mother
Until she's fully weaned at 18 months.
Mom and joey may look relaxed,
But josie is still vulnerable.
An at-foot joey is not easily able to defend herself from attack
And she still needs her mother for protection.
Julia needs to be on her guard
And keep a constant eye on what's around her.
But mother and joey are far from alone.
They have protection all around them.
Julia will be making sure that they're never too far away
From their wider group of eastern grey kangaroos...
..Known as a mob.
For kangaroos, a mob is like their social network.
It's a fluid arrangement
Where anything between two and a hundred animals
Cluster together to feed.
Members will come and go as they please,
Constantly shifting - even from hour to hour -
Depending on the availability of food.
Kangaroos don't necessarily live in family groups,
But males and females are part of the same mob,
And females who are related often stay close to each other.
As well as moms and joeys,
There will be a number of males
Who compete with each other for mating rights.
(growls)
Here, there's teenage boy barney, who's not quite mating yet,
But stands showing off by trying to look as big as he can.
And nearby, cyclops - a distinctive-looking young male.
He's got a damaged eye,
But this doesn't affect his ability to vie for dominance.
This casual group in fact has benefits for all of them.
Grouping together gives the mob greater security against predators.
Kangaroos - and, in particular, young joeys -
Are at risk of being attacked by snakes...
..Birds of prey...
..Foxes...
..And dingoes.
Australia's apex predator, the dingo, is a keen hunter...
And a kangaroo on its own can be an easy target.
A dingo can conceal itself in the undergrowth...
..Then move at high speed.
Its powerful jaws can take out a vulnerable joey in moments.
Feeding out on the open pasture,
The kangaroos never know what threat could be lurking nearby.
As foraging herbivores, they all need to eat for many hours each day
To get enough nutrition from the grasses.
So group protection is essential
To maximize feeding time.
The kangaroos can collectively use
Their strong sense of hearing for danger...
..Frequently raising their heads to check.
It's called shared vigilance.
The group relies on all its members keeping alert
To enable them all to feed more safely.
Adolescent barney may be showing off,
But he's also got a keen eye on what's going on around him.
He's part of the 'bubble of awareness'
The mob sets up for safety.
Researchers here define any animals within 50 feet of each other
As being part of the same mob.
Within that space, the kangaroos will react to each other's movements,
Alerting others to danger.
Female kangaroo stripes
Stops chewing and raises her head.
A sign that she's on high alert.
Kangaroo eyesight is poor but stripes has excellent hearing
And can swivel her ears in different directions
Without moving her head.
Stripes is the first to move.
As soon as one kangaroo bolts, it triggers a mass departure...
..And all of them take off at speed.
Kangaroos are the only large animals
To use hopping as a means of locomotion
And eastern greys' powerful hind legs
Can propel them at up to 39 miles an hour.
So the mob can quickly scarper from open grassland
To the protection of the woods nearby.
Adult kangaroos instinctively trust the safety of the mob.
But joeys testing out their independence
Can pose a challenge for their mothers.
It's midmorning and julia's peacefully feeding,
With her joey josie nearby.
Josie is distracted by two other kangaroos greeting each other.
Kangaroo kissing is thought to be a sign of social acceptance.
Curious josie doesn't wait for her mother.
Within seconds, josie is out of julia's immediate gaze
And now she's at risk.
On a nearby tree, there's a large goanna,
A carnivorous reptile almost three feet long...
..And with sharp teeth and claws.
It can unhinge its lower jaw
To make easy prey of a joey of this size.
Reproductive females are often
The most vigilant kangaroos.
Julia is quick to realize that josie has moved too far for safety.
She springs into action.
This time, josie's lucky.
And now julia is staying close.
While kangaroos are always alert to danger,
A mob can learn to adjust its behavior
Depending on the level of threat.
The anglesea golf course, south of melbourne,
Is home to a large colony
Of around 250 eastern greys...
..Who make good use of the well-kept greens...
..And don't seem too troubled by the presence of golfers.
Among the anglesea kangaroo population
Are five-year-old male captain,
Four-year-old female teni...
..And teni's one-year-old joey.
Teni is one of a number of kangaroos
Being monitored on the golf course,
So she wears an identity collar.
Although, like the rest of the mob,
Captain and teni are completely wild kangaroos,
They have learned to live in close proximity to humans...
And flying golf balls.
These grassy spaces
Give the kangaroos excellent grazing
And the lack of cover means fewer predators too,
So the mob can forage for longer.
Scientists have been studying
The mob behavior of these kangaroos
And they have discovered
That captain and teni are very unusual.
They appear to be a couple.
Usually after mating, the male has little to do
With either the female or any offspring
And males will often move between different mobs
In search of new mating partners.
But captain and teni are constantly together.
Captain is most likely the father
Of teni's at-foot joey...
..As well as the next joey
That is clearly visible in teni's pouch.
A tight little family unit like this
Is rarely seen in kangaroo mob society.
Their behavior could be the result
Of the protective environment of the golf course.
And it seems that they look out for each other
More than wilder kangaroos would.
Teni has been separated from the mob
By researchers, who want to give her a health check.
Captain and the joey watch anxiously.
Sensing potential danger,
Captain leads the joey away from the golf course.
The joey sticks close.
And captain seems to be keeping an eye out
For the young kangaroo,
Something a large male would never normally do.
They end up in the playground of a nearby school.
They seem unsettled without teni.
Captain sticks with the joey
Until he deems it safe to return to the green.
And this unconventional family group is reunited.
Back at sundown,
Stripes appears to be ill.
She's an older female,
But still has another joey just visible in her pouch.
She's lying with her head on the ground.
In this position, she can't be vigilant for possible danger.
It's a tell-tale sign that something is wrong.
She seems to be cold,
Wrapping her arms around herself to keep warm.
One of stripes' regular mob mates naomi lies beside her.
While mobs are fluid arrangements,
Kangaroos can show social preferences
And females in particular can form bonds with others.
Naomi's presence gives some protection to stripes
While she's laying low.
Kangaroo mobs are not territory-based...
But many female kangaroos like stripes and naomi
Will stick to a regular feeding area of around 37 acres...
..Known as a home range.
This may widen, depending on how much food and water are available.
Sticking to a home range
Ensures that the kangaroos can draw on experience
To optimize the time and energy needed to forage.
Mobs are often made up of kangaroos
Whose home ranges overlap as part of the wider social network.
But that doesn't mean that all their social interaction is friendly.
Females don't have a hierarchy,
But those that are more assertive
Can gain access to better food or space...
..Or, in high temperatures, areas of shade.
As a new dawn breaks over sundown,
Delilah is searching for the best spot to forage.
Arriving at the edge of the forest,
She reacts at the sight
Of another kangaroo who's already there.
Aggression between kangaroos is often vocal.
(growls)
A female will growl if another kangaroo
Who's not one of her usual mob mates
Tries to feed too near to her.
(growls)
Delilah growls.
(growling)
To enforce the point, she gives chase.
(coughs)
A cough is the kangaroo sign of submission.
(grunts)
The other kangaroo's retreat
Means that delilah has won the feeding spot.
Meanwhile, male kangaroos
Have a much more obvious dominance hierarchy than females,
Based around size and their ability to win mates.
Males will move around more
And some of the largest males are only seen at sundown
During peak breeding season.
Younger males will vie for supremacy,
Trying to work their way up the pecking order.
As they reach their adolescent years,
They will gradually move further away from their mom's home ranges
And will spend more time checking out females.
Larger stature indicates higher rank.
Barney and cyclops haven't yet reached the big, beefy standard
Of full-blown adult males.
But they'll certainly take every opportunity
To show the others that they mean business.
Standing tall - called a 'high stand' -
Is a primary show of dominance.
While ostentatious scratching is another show of power.
The males will keep a close eye on each other.
And when one tries a move on the females...
..Another will use aggression to warn him off.
(growls)
Early morning and adolescent male xavier
Is in the forest with a young female.
Males will often cluck at female kangaroos to show their interest.
(clucks)
He's not quite big enough to mate yet,
But that won't stop him trying.
So he sticks close to her, clucking wherever she goes.
(clucks)
(continues clucking)
These kangaroos are part of a mob
That heads over to the dam.
Kangaroos are well adapted to go several days without drinking
In the hot, dry summer.
But when more water is available during the cooler months,
They'll drink regularly.
Cyclops is also drinking at the water hole.
And he's tense.
It's windy, which makes the kangaroos nervous.
It means they are less able to hear other sounds
Which could alert them to danger.
To add to his tension,
Cyclops has spotted xavier wooing the female.
Both males are of similar stature,
So cyclops could challenge him for the female's attention.
(clucks)
Xavier launches a fresh round of clucking.
(clucks)
Cyclops moves to assert his dominance.
He barks loudly at xavier.
(barks)
Cyclops' aggression is enough to establish dominance
And xavier retreats.
He moves to a safe distance from cyclops...
..Who stands guard to keep him away.
She may not be ready to mate either of them
But cyclops is still going to practice his power play.
Having won her grazing spot earlier,
Delilah is taking some time to groom...
..Checking for ticks,
Which can embed themselves in her fur.
But as soon as she sets off in search of more foraging,
She's quickly got another young female in her sights.
Delilah moves in,
Threatening her with growls.
(growls)
(growling)
But aggression like this doesn't always pay off.
(growls)
When the other kangaroo stands her ground,
Delilah gives up.
She simply has to continue her feeding
With another kangaroo nearby.
Male and female kangaroos might fight over different things...
..But when food sources get scarce,
The aggression between all of them can intensify.
It's dusk and the mob has descended
On an area of soil rich in salt and minerals,
Known as a salt lick.
While the kangaroos' diet is mostly grass and plants,
They nibble the soil in these pits
To replenish the nutrients they need.
Kangaroos are unable to sweat,
So in summer, they lick their arms.
The evaporation of their saliva helps shed excess body heat.
This could lead to salt deficiency.
There is little salt in grass,
Whereas the soil in these pit areas
Has been found to be high
In salt, sulfur and magnesium.
But there are only two areas like this in sundown,
Meaning that the 'licks' can be fiercely contested,
Especially as there's only room at each pit for one or two at a time.
And once a kangaroo has got control of a salt lick,
Aggression clearly pays.
(growls)
Delilah has got the best position in the center of the salt pit.
(growls)
She's older and slightly bigger than the other females.
(growls)
And by adopting an aggressive stance
And growling whenever they attempt to approach,
She can prevent the others from feeding at the same time...
..Ensuring all the more for herself.
This is not due to a hierarchy.
Researchers here have noticed
That some kangaroos simply have more assertive personalities.
And that older females in particular
Can be more intolerant of others.
(growls)
The other females' failure to retreat fully
Prompts delilah to escalate her aggression.
(growls)
Batting the others away proves an effective strategy.
(growls)
Delilah's repeated domineering behavior
Ensures that the more submissive kangaroos don't retaliate.
Her intimidation of the others
Means she can keep the salt lick all to herself.
At the other pit, josie is trying to feed from julia.
By growling and batting her joey away,
Julia could be signaling
That she wants josie to wean.
Over at delilah's pit,
Her domination of the lick is proving short-lived.
(growls)
This kangaroo is refusing to be deterred by delilah's scare tactics.
(growls)
(growls aggressively)
Proof that standing up to a bully can pay off.
Out on the pasture, things are more peaceful.
Stripes is on the mend.
She's back on her feet.
Mothers groom their joeys in preparation for the night ahead.
And the other members of the mob get in their last grazing before dark.
They'll spend the night in the forest,
Sleeping and then foraging in the early hours.
But as nightfall approaches...
..The struggle at the salt lick
Shows no sign of dying down.
And when males join in the action,
The dynamic quickly shifts.
Cyclops joins delilah's pit.
And she defers to him.
At julia's pit...
(growls)
..Her irritation at her joey's repeated attempts to suckle is mounting.
This time, josie gets a smack...
..Before mom calls it a night.
Delilah wastes no time
In moving in on the vacated space.
Cyclops might be able to dominate the females
But another male is watching from the sidelines.
Barney.
(growls)
His growls as he approaches show that he's exerting his authority -
And expects submission.
(growling intensifies)
(growls)
(growls aggressively)
Cyclops' attempts at getting rid of him are futile.
Shaking his ears is a way of showing he means business.
Cyclops retreats
To join delilah on the sidelines.
But once barney's asserted himself as top kangaroo,
He's willing to let others feed from his pit.
And some of the other females get their chance at last.
Life as a kangaroo is full
Of surprising dangers, dramas, risks and rows.
But at the end of the day, and away from the salt licks,
Calm is restored.
The kangaroos can return to the safety of the forest...
..And a quiet night ahead of them
As peace-loving, grass-munching herbivores once more.
♪♪