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00:02Australia, a vast country of breathtaking natural beauty, teeming with extraordinary
00:10and iconic animals. And nothing says down under quite like a kangaroo, renowned for
00:19their springy locomotion and boxing brawls. They're the most successful species of the
00:28mammals known as marsupials. These kangaroos are eastern greys. They're prolific breeders
00:40and raise their young in pouches. But bringing up baby is fraught with challenges. Predators,
00:55climactic extremes and extremely lively joeys mean kangaroo mums face a daily struggle to
01:07keep their offspring alive. This is the secret life of the kangaroo.
01:31Sundown National Park in Australia sits on the border of New South Wales and Queensland. A rugged wilderness with rolling
01:40hills, deep river valleys and mountain peaks.
01:45rising to over 3000 feet. Down in the lowlands, the park is home to around 300 eastern grey kangaroos.
02:01This large colony lives permanently here, feeding in the forest by night and out on the open pasture
02:08by day. For many of the females here, child rearing is a constant preoccupation.
02:18Eastern greys are prolific breeders. Each year the park sees the arrival of around 150 new joeys, the name used
02:27for all baby marsupials.
02:30And like all marsupials, kangaroos give birth to undeveloped young, which they raise in a specialised pocket, known as a
02:39pouch.
02:47Females can reproduce more than once a year, with family life somewhat resembling a production line.
02:56In fact, a female can have three babies all at different stages of development.
03:01She can have one young at foot, living beside her on the ground.
03:08Another small joey growing inside her pouch.
03:12And be pregnant with a third baby in waiting.
03:18The embryo of the third joey can be in a state known as dire pause.
03:22The pregnancy is literally on pause until there's more room in the pouch.
03:32But while this is an incredibly efficient way of ensuring maximum production of young,
03:38raising even one joey to an independent kangaroo that can fend for itself is extremely difficult.
03:47Around 50% of the joeys here don't make it.
03:52At each stage of the joey's development, mothers have to struggle to keep them well nourished and safe from predators.
04:04And it's something the females have to do alone.
04:08After mating, the males play no part in the raising of their young.
04:15Everything is down to mum.
04:26This is Lauren.
04:29Named by the researchers who are studying the breeding patterns of the kangaroos here,
04:33to find out more about why only some joeys survive.
04:42Despite numerous attempts in the last four years, Lauren hasn't been able to successfully raise a joey past 18 months
04:49old.
04:50For some mums, this is a common occurrence.
04:54While others seem to find the challenge of raising a joey far easier.
05:03But Lauren's managed to get her latest baby, butterscotch, to nine months.
05:10The little joey is healthy, and now she's in and out of the pouch.
05:14So far, all is well.
05:18But the next six months will be critical.
05:22And everything will depend on Lauren.
05:31Only when the time is right, when her daughter has learned how to stay safe from harm,
05:38will Lauren let her go and fend for herself.
05:59A fully grown eastern grey may reach just under five feet tall.
06:04But when it's born, it's very undeveloped.
06:07And just an inch long.
06:12Kangaroos give birth 30 days after mating.
06:15Much sooner than other mammals of a comparable size.
06:21At birth, the tiny joey is more like an embryo than a baby.
06:25And once born, it crawls up the fur on the underside of its mother's belly, into the pouch.
06:35Inside the pouch, the hairless joey, little bigger than a jelly bean, finds its way to one of four teats.
06:43It's unable to bite down, so the pointed end of the teat expands inside its mouth to stop the joey
06:49falling off.
06:51Once the joey latches on, it will only feed from the one teat until it weans.
07:00The pouch is a complete life support system, providing everything a growing joey needs.
07:07Food, warmth and shelter from the elements.
07:11And it'll be its home for the next 11 months.
07:17Special sphincter-like muscles in the pouch opening keep the joey safe inside, while mum has her nose to the
07:24ground, grazing.
07:28Pouches are an efficient method of reproduction.
07:30So much time in the pouch allows a joey to do lots of growing before it has to face the
07:36outside world.
07:54After around six months safely nestled inside the pouch, a young joey will poke her head out for the first
08:00time.
08:07This is Poppy.
08:10Her mum Tilly needs to graze constantly to ensure she is making enough nutritious milk for her new joey.
08:21Poppy has just begun to take a look at the outside world and is yet to leave the safety of
08:27her mother's pouch.
08:30In around three months time, she should be ready to take her first bouncing steps on her own two feet.
08:37But she has a lot of growing to do first.
08:42She won't start to get her full coat of dense fur until around nine months.
08:48For now, her hair is fine and smooth.
08:54Her face is slightly pinker, especially around the nose, and her eyes are large and out of proportion with the
09:01rest of her head.
09:04Poppy is what is known as a pouch young.
09:07And life right now consists of staying safely within her climate controlled envelope.
09:15She's protected against predators and from Australia's changeable environment.
09:24But as she grows, she will increasingly poke her head outside to sneak a peek at what's going on around
09:30her.
09:31Kangaroos are herbivores, spending the majority of their time grazing grasses and flowers.
09:37Joeys learn by watching other kangaroos.
09:41So at around seven months old, while still tucked safely in the pouch,
09:46joeys taste their first mouthful of grass.
10:12Over the next two months, legs get longer, heads get bigger, and tails get thicker.
10:23Eventually, after nine months in the relative safety of mum's pouch,
10:26it's time to leave that protective pocket.
10:29And take the first tentative hops into the great outdoors.
10:34They've had a bit of a preview of what to expect from the outside world.
10:39But it's almost like a second birth.
10:46This joey has just begun to explore on his own.
10:51Each time taking longer and longer sorties away from his mum.
10:58After so long in the pouch, he's not very experienced at moving around.
11:04Hopping might come naturally, but it still takes coordination and practice.
11:10He's got to learn just what those great big gangly legs can really do.
11:16This time in a joey's life is known as the in and out phase.
11:20And lasts for the next month or two.
11:23After his brief foray into the outside, he's keen to get back home.
11:31But mum and joey need to work as a team.
11:34Both need to be in the right position for him to find his way back in.
11:39Mum needs to lean forward to create the necessary slack in the pouch opening
11:44for the youngster to clamber his way in.
11:48She also needs to lower her arms and hold them out to the side.
11:53But researchers here have noticed that this doesn't always come easily to some mothers.
12:00If this mum doesn't adopt the right position soon, it could lead to the joey becoming exhausted before he can
12:06get back in safely.
12:09Outside, her joey is completely defenceless.
12:14Predators could be watching.
12:18Carnivorous lizards called goannas live in sundown.
12:25As do predatory snakes.
12:29It's not venomous, but this carpet python would easily crush an at-foot joey.
12:36They hunt by stealth and ambush.
12:41They use heat-sensitive pits on the tip of their noses to detect tiny changes in temperature,
12:47which help them locate warm-blooded prey like kangaroo joeys.
12:55Killing is by constriction.
12:58This suffocates the prey.
13:02A joey that strays too far from the protection of its mother could be swallowed whole.
13:10At last, mum bends down and the inexperienced little joey has his opportunity to return.
13:18But now he's missing the signal from mum.
13:23Finally, her arms are out and he gets the message.
13:29He's back in, away from any hungry predator.
13:41At any stage, it can be hard for a mother kangaroo to keep her joey alive.
13:50Drought, predation and disease can all take their toll on vulnerable young kangaroos.
14:20Controlling a joey, while keeping alert to dangers, can be a testing time for young mothers.
14:24as new mum Tilly is finding out.
14:33Now, at nine months old,
14:35her baby Poppy is consistently out on her own two feet.
14:41Her legs are still a bit too big for her body,
14:44but she's bursting with energy.
14:55Poppy's playful antics leave attentive mother Tilly
14:58little time to concentrate on feeding herself.
15:02When Poppy's not in the pouch or feeding from it,
15:05Tilly needs to be sure she's constantly aware of where her baby is.
15:19Kangaroos don't have great eyesight.
15:23While their sense of smell is good,
15:26their secret defence weapon is their ears.
15:32Kangaroos have very good hearing.
15:37Each ear can be moved independently
15:39to scan the surroundings for any sign of danger.
15:47When Tilly decides it's time to move on,
15:49she bends forward to signal to Poppy to get in the pouch.
15:54But Poppy has other ideas.
16:11Learning to hop at high speed
16:12is actually an essential skill for a growing joey.
16:17And Poppy is starting to get the hang of it.
16:23This spirited bouncing back and forth
16:26is known as rapid running.
16:28As she ventures away from mum
16:30and puts her legs to the test,
16:34her huge Achilles tendon works like a giant elastic band.
16:37Each rebound gives her energy back for the next hop.
16:42Once she's an adult,
16:43she'll be able to hop at over 40 miles per hour.
16:46But for now,
16:47this short dash is fast enough for her.
16:50And she quickly scampers back again.
16:57Poppy swings her paws at mum
16:59and hops off.
17:01Adult kangaroos often settle disputes by boxing.
17:05And Poppy has decided mum is good for target practice.
17:10Tilly keeps up her patient attempt
17:12at getting Poppy into her pouch.
17:17But Poppy sneaks in a quick right hook.
17:24Play fighting and learning to box
17:26is all part of a joey's development.
17:30Scratching and sniffing
17:31is usually the precursor
17:32to a bit of play boxing.
17:36But you need to make sure
17:37you have a willing sparring partner.
17:40While this all seems lighthearted,
17:43this play has a serious side.
17:45And it's how crucial life skills are learned.
17:49In later life,
17:51fights are used for establishing hierarchy in the mob.
17:55It's mainly the males who fight.
17:59But females can get into scraps
18:01over access to food or space.
18:06However,
18:07tolerant Tilly has had enough fun for one day.
18:11Eventually, after a quick feed,
18:12she manages to get Poppy back in.
18:15Now with Poppy inside her pouch,
18:18she can focus on feeding herself for a while.
18:22Tilly still needs to remain vigilant.
18:28Like her joey,
18:29she too is vulnerable to certain predators.
18:34The wedge-tailed eagle,
18:37the largest bird of prey in Australia,
18:40has been known to attack kangaroos.
18:43A huge, powerful eagle
18:45with a distinctively long, diamond-shaped tail.
18:48It's capable of taking prey several times its own weight
18:53and can easily pick off a young joey.
18:59And wedge-tailed eagles sometimes hunt cooperatively in pairs
19:03or even in small groups.
19:05When they do,
19:07these formidable hunters could kill a large adult kangaroo.
19:19Protective mothers work together, too.
19:25Both mothers, Tilly and Lauren,
19:27are part of a group of kangaroos
19:28known as a mob.
19:33By staying close to other females,
19:35the extra ears listening out for predators
19:37help to keep their joeys safe.
19:41Hopefully this year will bring Lauren more success.
19:45Over the last four years,
19:47she has lost all her joeys.
19:50Most likely predators took them.
19:54This is a critical time for butterscotch.
19:58For now, Lauren waits patiently
20:00as young butterscotch ventures further from her side.
20:05She might appear calm,
20:06but her twitching ears betray
20:09that she's listening carefully
20:10for butterscotch's movements.
20:35It's early morning
20:36and Lauren's cleaning her pouch.
20:41After a night inside,
20:43butterscotch is still tucked up.
20:46Cleaning a pouch is one of the first signs
20:49that a kangaroo is preparing for a new arrival
20:51and is about to give birth.
20:55And once she has a joey in the pouch,
20:59keeping it clean is an essential part of its care.
21:08She uses her long tongue
21:09to lick the inside of her pouch clean.
21:17When very small joeys are still inside,
21:20this licking will stimulate them to defecate.
21:23Mum then consumes the faeces.
21:27And while this doesn't sound very appetising,
21:30it's a highly efficient way
21:31of reabsorbing any fluids
21:32the mother has lost from nursing.
21:37With an older joey,
21:38it's also important to ensure
21:40that mum removes any mess
21:41that's been brought in
21:42with the constant hopping in and out.
21:48As well as pouch cleaning,
21:50all kangaroos,
21:51male and female,
21:53need to groom themselves regularly.
21:55In the summer months,
21:57ticks become a real nuisance.
22:00And joeys need to be kept tick-free too.
22:19Grooming is an essential part of bonding
22:21between mum Tilly
22:22and her daughter Poppy.
22:27If mum can get the mischievous joey
22:29to stay still for long enough.
22:45So when Poppy returns for some milk,
22:47Tilly seizes the opportunity
22:49to do some more grooming.
22:54And the young joey even gives it a go herself.
23:00Once she's weaned,
23:01mum will leave Poppy to do her own grooming.
23:04So she needs to be well practised.
23:08Tilly can't seem to keep hold of her joey
23:10long enough to finish the job.
23:28She uses her forearms
23:29to hold her daughter in place.
23:31But the joey soon wriggles free again.
23:35This grooming is about more than just
23:37removing irritating parasites.
23:40Ticks carry diseases.
23:42And youngsters like Poppy
23:44are especially vulnerable.
23:49With their immature immune systems,
23:52they'll be more susceptible
23:53to catching diseases from the ticks.
23:57The parasites feed on the joey's blood.
24:00And if an infestation is bad enough,
24:02the loss of blood alone
24:04will take its toll on her development.
24:12After dealing with a fidgety joey,
24:15mum turns her attention
24:16to her own body,
24:18most of which she can reach herself.
24:22But for those hard to get at places,
24:24there's help at hand.
24:27The willy wagtail is named
24:29for the characteristic sideways waggle
24:31of its tail.
24:35They're often found hopping
24:37about the grass,
24:38picking off insects disturbed
24:40by feeding kangaroos.
24:45But they're also partial
24:46to a blood-sucking tick or two.
24:50And the kangaroos welcome
24:52the help in removing the parasites.
25:23And peoplerineirls
25:23And they're like,
25:26Those young kangaroos that have made it from small pouch-bound babies to tentative explorers
25:32are still reliant on their mothers until they're around 18 months old.
25:47As the time approaches for the joeys to leave, space in the pouch gets ever tighter.
25:55Their legs are now far too long and they stick out awkwardly.
26:02A mother will be carrying around at least 11 pounds of joey by now.
26:12Tilly's daughter Poppy has grown very large and will soon leave the pouch permanently.
26:19She's still up to her old tricks.
26:23This time, she kicks mum instead of boxing her.
26:32She still takes regular drinks of her mother's milk and Tilly diligently remains alert while
26:38her daughter feeds.
26:44The wind has picked up, which makes it far harder for Tilly to hear the sounds of any approaching
26:50threat.
26:53She prefers Poppy in the safety of her pouch.
26:58She's clearly not prepared to let the large joey fend for herself just yet.
27:07But hopping is increasingly difficult with such a large load.
27:14Poppy's arms and feet can no longer fit inside the pouch at all.
27:20She won't have many nights left in the protection of her mother's pocket.
27:47During this time, when their joeys are spending more and more time out of the pouch exploring,
27:52mothers tend to segregate themselves from the mob.
28:05Researchers believe this may be to reduce the chances of the increasingly adventurous joeys
28:09getting confused and losing their mothers when there are so many other adult females around.
28:22a joey can jump into the wrong pouch when frightened.
28:26One study DNA tested wild eastern greys and made the surprising discovery that almost 5% of
28:34joeys get adopted by a new mother during the in and out phase.
28:39If Poppy's scared enough to attempt entering a random pouch, there's every chance that the
28:45adoption might stick until she's independent.
29:05It's summer now and as the weeks and months pass at sundown, the ground becomes increasingly parched.
29:21There's been very little rain and after an unusually dry spring, sundown is in the grip of drought.
29:31Conditions like this can have a huge impact on joey survival rates.
29:35In 1982, a drought caused eastern grey populations to crash by 40%.
29:44Kangaroos can go a long time without a drink because they get most of the fluids they need from the
29:50foliage they eat.
30:00However, hot temperatures dehydrate the kangaroos.
30:08And the plants they feed on.
30:13So they'll need to drink more water.
30:22But this can be a risky business.
30:29This mother has a joey in the in and out phase.
30:34And has separated herself from the mob.
30:38Alone, she's lost the protection of the mob's collective senses.
30:48She's extremely cautious as she nears the edge for a drink.
30:56Predators often stake out water holes in dry season, knowing thirsty kangaroos will be drawn to water.
31:04It's a dilemma, but the need for fluids overwhelms the risk of being so exposed.
31:13Mother and joey are far from cover should they need to make a run for it.
31:33And fleeing at high speed on the rocky terrain of the dry river bed would be difficult.
31:40But after drinking her fill, she makes it back to the relative safety of the tree line.
31:58Here at sundown, summer daytime temperatures can rise to 105 degrees Fahrenheit.
32:08Kangaroos can't sweat, so to keep cool, they lick themselves.
32:14As the saliva evaporates, it cools their blood.
32:20It's very hot for a youngster inside the pouch.
32:23So to help keep her joey cool, this mother has licked the fur on the outside.
32:31As the moisture evaporates, it cools the joey inside.
32:39While finding drinking water and keeping cool is a challenge, at this time of year it's access to good grazing
32:46that makes it increasingly difficult for mothers to support their joeys.
32:51The only green shoots to be found are in what remains of a water hole.
32:57The water has completely dried up, but there's still enough moisture in the earth to support new plant growth.
33:06The tough pond vegetation is by no means ideal.
33:11But with so little greenery, these two kangaroos are competing for what's there.
33:23The contest is short-lived. One kangaroo quickly backs down.
33:30The weaker of the two has to resort to the poor brown grass in the dry meadow.
33:39Being prevented from getting enough good grazing has had severe consequences.
33:46She has a very saggy pouch opening.
33:51Her coat is raggedy and worn looking, and her joey is nowhere to be seen.
33:59She's not in full health.
34:01If a mother is struggling to produce milk and to get sufficient nutrition for herself,
34:08she can decide to save herself rather than risk both mother and joey starving.
34:21A pouch like this is a sign that it's suddenly been vacated by a joey.
34:27Either her joey came out and was too small to find its way back in,
34:32or she may have deliberately ejected it.
34:56At a year old, butterscotch is now the oldest joey Lauren has managed to raise in the last few years.
35:06Despite the challenges brought by the lack of rain and poor quality grazing,
35:11butterscotch is no longer living in the pouch.
35:16She's young at foot.
35:27And Lauren is already attracting male attention again.
35:33This male smells Lauren's urine.
35:38He can detect hormones that will tell him if she's ready to mate again.
35:47But he doesn't get the message he wants.
35:53Kangaroos are able to pause a pregnancy while they have a pouch young.
36:01Lauren may have had one of these paused embryos in waiting,
36:04as she already has a new joey growing in her pouch.
36:11She won't be ready to mate again for a few months yet,
36:15which is why the male isn't interested.
36:36As the heat intensifies, Lauren finds it harder to get enough food.
36:43Even though butterscotch is eating grass, she isn't weaned yet,
36:48so is still placing demands on her mother.
36:56And with a new joey in her pouch, Lauren must produce milk for two.
37:09Lauren's struggling. She's become very thin.
37:23One of the most remarkable aspects of kangaroo physiology
37:27is their ability to allocate different types of milk to offspring of different ages.
37:34Butterscotch will have been feeding from the same teeth since she was born,
37:38and it's now stretched and elongated.
37:45When she weans, it'll shrink back to its original size for a new baby to latch onto.
37:56By only feeding each joey from one of her four teeths,
38:00Lauren's able to reserve the premium high-fat content milk for her new young.
38:10Butterscotch will get poorer quality, thinner milk.
38:17And soon, she'll need to switch to a grass-only diet.
38:27She must be healthy and prepared for when her mother decides
38:31it's time to cut off the milk supply.
38:37So before she weans, butterscotch needs to greatly increase
38:40the amount of time she spends foraging.
38:46For now, the joey still sticks close to her mother's side.
38:50This is the most dangerous time in a young kangaroo's life,
38:54when joey mortality is at its highest.
38:59They no longer have the safety of the pouch,
39:01but aren't yet independent and aware of all the dangers.
39:14Lauren's preoccupied by feeding.
39:19She needs to forage for most of the day to get enough nutrition from the grass.
39:31But while Lauren's grazing, butterscotch is drifting,
39:36further and further away from mum.
39:45The young joey finds herself on the edge of the forest.
39:58She heads back towards the mob,
40:00but encounters a group of kangaroos she doesn't recognise.
40:05Lauren is nowhere to be seen.
40:14Lauren risks losing another joey before reaching the weaning stage.
40:21Butterscotch calls for her mother.
40:27Lauren has her head raised.
40:30She seems to be aware that something's up.
40:35Butterscotch calls for her mother again.
40:40She's getting distressed.
40:45Finally, Lauren gets the message.
40:48And it's her turn to call out to butterscotch.
40:51This is known as clucking,
40:53and is usually a signal to joeys to get into the pouch.
40:57But butterscotch is now a good way out of earshot.
41:04Although butterscotch is close to other kangaroos who could alert her to danger,
41:10they won't protect her if a predator appears.
41:28Lauren finds a baby, but it's not butterscotch.
41:37She continues her search for her daughter.
41:42There's a salt lick in sundown.
41:46An area of soil where kangaroos gather to lick up essential minerals.
41:52Perhaps butterscotches followed the mob there.
42:00But she's not here.
42:05Lauren stands still and scans the horizon.
42:13Using her eyes, her sense of smell, and her highly sensitive ears.
42:20And this time, Lauren hears her.
42:34All she has to do now is home in on her joey's position.
42:51Butterscotch has got her ears working overtime too,
42:54twitching around in all directions, trying to hear her mum.
43:25Finally, they're reunited.
43:44For now at least, Lauren sticks to her daughter's side as they head for the safety of the forest.
43:51For now.
44:20To be continued.
44:31But while Lauren and Butterscotch are safely back together, Tilly is now alone, her precocious
44:44mischievous Poppy is nowhere to be seen. When Poppy was last seen, she was still in and out
44:56of the pouch. But she hasn't made it past the tricky transition to becoming an independent
45:03young at foot. It's possible her unwillingness to heed her mother may have led to her demise.
45:13She was just too bold, too soon. Around half of all joeys die before reaching adulthood.
45:37However, the high frequency of kangaroo reproduction ensures that numbers are healthy enough to
45:43sustain the population.
45:54Kangaroos are in fact very successful. There are 16 million eastern greys in Australia.
46:11And this success is in part thanks to the constant cycle of reproduction by kangaroo mums and their pouches.
46:26For Lauren, the toll of raising two joeys simultaneously has been worth it. She has a healthy, independent
46:35daughter. And things are looking up. The rains have returned. The lakes and rivers have been replenished.
46:47And there's fresh new grass, making life a little easier. Butterscotch has learned all she needs to survive by herself.
47:00And in just six months, she could be having little joeys of her own.
47:18The lakes and rivers are then earth. She has fainted, where she has grown up.
47:21And all the other things are floating around. The lakes and rivers have been refuge in the world before
47:29under the place of leaving to desens or at night. The lakes of the lakes and rivers have been
47:31off. And there are many of the lakes. The lakes and rivers have been reduced to the claimed