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Stretching out before me is the magnificent Yellowstone. | 0:00:08 | 0:00:13 | |
This is one of the most dynamic... | 0:00:18 | 0:00:20 | |
..unpredictable and exciting environments on Earth. | 0:00:22 | 0:00:26 | |
Deep in the Rocky Mountains, | 0:00:32 | 0:00:33 | |
this vast wilderness is home to North America's | 0:00:33 | 0:00:37 | |
most iconic wildlife. | 0:00:37 | 0:00:38 | |
But every year, Yellowstone's animals are pushed | 0:00:44 | 0:00:47 | |
to their absolute limits. | 0:00:47 | 0:00:48 | |
Temperatures can swing from -40 in winter | 0:00:50 | 0:00:53 | |
to approaching plus 40 in summer. | 0:00:53 | 0:00:56 | |
And at the heart of this change is the thaw. | 0:00:56 | 0:01:00 | |
The melt can last from March to July... | 0:01:01 | 0:01:03 | |
..and it's one of the most dramatic, natural events on Earth. | 0:01:05 | 0:01:10 | |
How do the animals cope with such extremes of temperature? | 0:01:10 | 0:01:14 | |
We're here to find out. | 0:01:16 | 0:01:18 | |
I'm joined by biologist Patrick Aryee... | 0:01:21 | 0:01:23 | |
That's intense. | 0:01:24 | 0:01:26 | |
..and a team of wildlife cameramen and expert scientists. | 0:01:27 | 0:01:30 | |
Previously, we've witnessed how animals survive | 0:01:35 | 0:01:39 | |
Yellowstone's extremes. | 0:01:39 | 0:01:40 | |
Starting in winter, it was well below freezing | 0:01:43 | 0:01:46 | |
and some animals really struggled. | 0:01:46 | 0:01:49 | |
Then, in spring, temperatures jumped nearly 30 degrees in a fortnight | 0:01:52 | 0:01:58 | |
and wildlife had to cope with the thaw coming three weeks early. | 0:01:58 | 0:02:02 | |
Now, summer is here and there are new challenges. | 0:02:03 | 0:02:07 | |
The meltwater will dry up fast, | 0:02:08 | 0:02:12 | |
food becomes scarce... | 0:02:12 | 0:02:13 | |
..and if there's no rain, | 0:02:15 | 0:02:17 | |
wildfires will threaten to destroy the habitats animals rely on. | 0:02:17 | 0:02:21 | |
SQUEAKING | 0:02:23 | 0:02:25 | |
Welcome to Yellowstone's Blazing Summer. | 0:02:26 | 0:02:28 | |
So far in 2016, | 0:02:46 | 0:02:49 | |
every month has been hotter than average in Greater Yellowstone. | 0:02:49 | 0:02:53 | |
If the trend continues, | 0:02:55 | 0:02:57 | |
summer could reach record temperatures | 0:02:57 | 0:03:00 | |
and push animals to the brink of survival. | 0:03:00 | 0:03:03 | |
Yellowstone lies over 600 miles | 0:03:08 | 0:03:10 | |
from the Pacific and has a continental climate, | 0:03:10 | 0:03:14 | |
which means summers can be relentlessly hot. | 0:03:14 | 0:03:17 | |
Now, at the moment it's all still looking quite lush and green, | 0:03:21 | 0:03:25 | |
but in the coming weeks as the temperatures continue to rise, | 0:03:25 | 0:03:29 | |
the vegetation will start to wither, | 0:03:29 | 0:03:31 | |
valleys will become dust bowls and lakes and streams | 0:03:31 | 0:03:34 | |
will start to dry up. | 0:03:34 | 0:03:35 | |
Wildlife must travel further in search of food, | 0:03:40 | 0:03:43 | |
drinking water and shelter from the heat. | 0:03:43 | 0:03:46 | |
Young animals born back in spring are now entering their first summer. | 0:03:48 | 0:03:53 | |
They're a lot more mobile, but still need to avoid danger | 0:03:53 | 0:03:56 | |
whilst exploring on those unsteady legs. | 0:03:56 | 0:03:59 | |
For this latest generation, | 0:04:04 | 0:04:07 | |
the change in climate will make their lives even more challenging. | 0:04:07 | 0:04:10 | |
In spring, the beaver family was affected by the | 0:04:15 | 0:04:18 | |
unusually warm temperatures. | 0:04:18 | 0:04:20 | |
Huge volumes of meltwater flooded into the Snake River, | 0:04:23 | 0:04:26 | |
where the beavers have made their home in the south | 0:04:26 | 0:04:29 | |
of Greater Yellowstone. | 0:04:29 | 0:04:30 | |
Snow melting from all the way up there in the Teton Mountains | 0:04:32 | 0:04:35 | |
rushed down in a deluge and threatened to wash | 0:04:35 | 0:04:38 | |
our beaver dam away. | 0:04:38 | 0:04:40 | |
Beavers dam rivers to create a series of ponds, | 0:04:42 | 0:04:45 | |
where they live and feed, safe from predators. | 0:04:45 | 0:04:48 | |
After working flat out on emergency repairs to the dam, | 0:04:49 | 0:04:53 | |
the beavers just managed to save their home from the flood. | 0:04:53 | 0:04:56 | |
Now, in summer, the family could face the opposite challenge - | 0:05:00 | 0:05:04 | |
too little water in the river. | 0:05:04 | 0:05:06 | |
I've come to meet wildlife cameraman Jeff Hogan | 0:05:08 | 0:05:11 | |
who's been following the beavers. | 0:05:11 | 0:05:13 | |
Hey, Jeff. | 0:05:15 | 0:05:16 | |
-How's it going? -There you are. How are you doing? | 0:05:17 | 0:05:20 | |
Jeff was filming great grey owls in spring. | 0:05:20 | 0:05:23 | |
Now, he'll use his specialist skills to study the beavers and has | 0:05:23 | 0:05:28 | |
installed an infrared camera inside their lodge. | 0:05:28 | 0:05:32 | |
SQUEAKING | 0:05:34 | 0:05:36 | |
I've got something to show you. | 0:05:38 | 0:05:39 | |
It was a bit of a surprise. | 0:05:39 | 0:05:41 | |
'This footage looks like the male and female I saw here in spring.' | 0:05:43 | 0:05:49 | |
-You see a couple of big, fat beavers? -Yeah. | 0:05:49 | 0:05:52 | |
SQUEAKING | 0:05:52 | 0:05:54 | |
'But then, something unexpected.' | 0:05:56 | 0:05:59 | |
Oh, my gosh! | 0:06:06 | 0:06:08 | |
PATRICK LAUGHS | 0:06:08 | 0:06:10 | |
-They're so adorable. -That's a great shot. | 0:06:10 | 0:06:13 | |
-Oh, my goodness. -That's amazing. | 0:06:15 | 0:06:17 | |
No way. | 0:06:17 | 0:06:18 | |
Oh man, they're so adorable. | 0:06:20 | 0:06:23 | |
'Baby beavers are called kits and Mum has given birth to three.' | 0:06:29 | 0:06:33 | |
I would say they're probably about ten weeks of age, maybe. | 0:06:35 | 0:06:38 | |
'Kits are precocial, | 0:06:41 | 0:06:43 | |
'which means they're mobile and quite advanced from birth. | 0:06:43 | 0:06:47 | |
'Emerging with a full coat of thick fur, sharp chisel-like teeth... | 0:06:47 | 0:06:51 | |
'..and a characteristic flat tail. | 0:06:54 | 0:06:56 | |
'This, they use as a rudder to steer when swimming, | 0:06:59 | 0:07:02 | |
'which they can do within a day of being born. | 0:07:02 | 0:07:05 | |
'But these three still rely on their family to bring them food | 0:07:07 | 0:07:10 | |
'from outside the lodge.' | 0:07:10 | 0:07:12 | |
I've got another clip for you. | 0:07:14 | 0:07:16 | |
SQUEAKING | 0:07:19 | 0:07:21 | |
Look at all that willow. | 0:07:21 | 0:07:24 | |
This adult beaver just brought in three or four branches, | 0:07:24 | 0:07:27 | |
all bundled up. | 0:07:27 | 0:07:28 | |
And the little young ones will just jump on this. | 0:07:32 | 0:07:35 | |
They'll gobble that right down. | 0:07:37 | 0:07:39 | |
'At ten weeks old, these kits have stopped drinking | 0:07:48 | 0:07:51 | |
'their mother's milk. | 0:07:51 | 0:07:52 | |
'They now have an adult diet.' | 0:07:52 | 0:07:54 | |
In summer, the ponds the beavers create | 0:08:00 | 0:08:02 | |
become their vegetable gardens. | 0:08:02 | 0:08:05 | |
The slow, warm waters create optimal conditions | 0:08:05 | 0:08:09 | |
for edible plants to grow. | 0:08:09 | 0:08:10 | |
Mum, Dad and last year's young are working overtime collecting food | 0:08:17 | 0:08:22 | |
for the kits and keeping the lodge clean by washing grassy bedding. | 0:08:22 | 0:08:26 | |
In a matter of days, | 0:08:41 | 0:08:42 | |
the kits will leave the lodge and learn to forage for their own food, | 0:08:42 | 0:08:46 | |
whilst avoiding predators. | 0:08:46 | 0:08:48 | |
Around 50% of beaver kits don't survive their first six months. | 0:08:50 | 0:08:55 | |
It's a critical time for this family, and Jeff | 0:08:55 | 0:08:58 | |
will be following them every step of the way. | 0:08:58 | 0:09:01 | |
Across Yellowstone, our teams have been documenting signs | 0:09:06 | 0:09:10 | |
that an early spring thaw kick-started an early summer. | 0:09:10 | 0:09:14 | |
As icy meltwaters flowing off the mountains subsided, | 0:09:16 | 0:09:21 | |
streams warmed rapidly in the sun. | 0:09:21 | 0:09:23 | |
And the surface of the water started to dance. | 0:09:25 | 0:09:29 | |
Rising water temperatures trigger mayflies to hatch in their millions. | 0:09:36 | 0:09:41 | |
These conditions are the starting pistol for an important event... | 0:09:55 | 0:09:59 | |
The arrival of cutthroat trout. | 0:10:03 | 0:10:06 | |
Many have spent the winter in Yellowstone's deep rivers and lakes, | 0:10:09 | 0:10:13 | |
but migrate upstream to feed on mayflies and spawn | 0:10:13 | 0:10:17 | |
in these shallow waters. | 0:10:17 | 0:10:19 | |
Every year, the arrival of these protein-rich fish creates a | 0:10:23 | 0:10:28 | |
feeding bonanza for river otters, mink, | 0:10:28 | 0:10:31 | |
bears and birds of prey, like eagles and osprey. | 0:10:31 | 0:10:36 | |
Over 20 different species of birds and mammals. | 0:10:37 | 0:10:41 | |
This year, the early snowmelt has given these predators a head start | 0:10:45 | 0:10:49 | |
to fatten up. | 0:10:49 | 0:10:50 | |
While summer temperatures have created a frenzy of activity | 0:10:56 | 0:10:59 | |
on the rivers, Yellowstone's low altitude grasslands | 0:10:59 | 0:11:03 | |
are eerily quiet. | 0:11:03 | 0:11:05 | |
'In spring, herds of elk and bison were feeding here, | 0:11:07 | 0:11:10 | |
'but they've moved on as the green vegetation withers in the heat. | 0:11:10 | 0:11:15 | |
'What the locals call "the brown-up" has begun.' | 0:11:16 | 0:11:19 | |
Over the course of just a few months, this ground has gone | 0:11:22 | 0:11:26 | |
from being covered in feet of snow to lush grass, | 0:11:26 | 0:11:28 | |
which has now scorched, died away and has very little nutrition. | 0:11:28 | 0:11:33 | |
So grazing animals like bison and elk need to move further up | 0:11:33 | 0:11:37 | |
the mountains in search of green shoots. | 0:11:37 | 0:11:39 | |
As the summer continues, the brown-up will creep higher. | 0:11:42 | 0:11:45 | |
Bison and elk must keep moving. | 0:11:48 | 0:11:51 | |
By July, bison have arrived at summer grazing grounds | 0:11:57 | 0:12:00 | |
on Yellowstone's high plateau. | 0:12:00 | 0:12:03 | |
This is the only time mature males and females come together | 0:12:06 | 0:12:11 | |
and herds can reach a thousand strong. | 0:12:11 | 0:12:14 | |
Scientists think this summer the bison will look | 0:12:15 | 0:12:18 | |
particularly impressive after an abundance of grazing | 0:12:18 | 0:12:21 | |
during a warm spring. | 0:12:21 | 0:12:23 | |
So Kate's gone to check out what kind of condition they're in. | 0:12:23 | 0:12:26 | |
Oh, my goodness! | 0:12:30 | 0:12:32 | |
What a magnificent beast. | 0:12:32 | 0:12:34 | |
The male bison at this time of year are truly just... | 0:12:36 | 0:12:43 | |
They are in their prime. | 0:12:43 | 0:12:45 | |
'Bulls have piled on up to 150kg of fat and muscle | 0:12:48 | 0:12:54 | |
'and now is their chance to start throwing that weight around. | 0:12:54 | 0:12:57 | |
'July is rutting season, when males duel for the right to mate. | 0:13:00 | 0:13:05 | |
'And this year's favourable conditions mean it will be fierce. | 0:13:05 | 0:13:09 | |
'The largest contenders could be tipping the scales | 0:13:11 | 0:13:13 | |
'at nearly a tonne.' | 0:13:13 | 0:13:15 | |
You may think, "Isn't it a little bit early for sex? | 0:13:18 | 0:13:21 | |
"I mean, you know, it's the summer, they should be chilling out." | 0:13:21 | 0:13:23 | |
But remember that bison are the first to give birth. | 0:13:23 | 0:13:27 | |
Think back to the spring, the first calves we saw, | 0:13:28 | 0:13:31 | |
they were bison calves. | 0:13:31 | 0:13:32 | |
'Female bison have one of the longest pregnancies here, | 0:13:35 | 0:13:39 | |
'lasting over nine months. | 0:13:39 | 0:13:41 | |
'So to time the birth of calves with the start of next spring... | 0:13:43 | 0:13:47 | |
'..these males need to get on with it.' | 0:13:49 | 0:13:51 | |
This male bison has found himself the perfect dust bath. | 0:14:01 | 0:14:05 | |
And, at various times throughout the day, he will roll in it, | 0:14:09 | 0:14:13 | |
he'll cover himself in dust, he'll pee in the dust | 0:14:13 | 0:14:15 | |
and roll in that. | 0:14:15 | 0:14:17 | |
Just to make sure that he smells as virile and ready for it as possible. | 0:14:21 | 0:14:26 | |
LOW GRUMBLE | 0:14:27 | 0:14:31 | |
'Wallowing in dust baths is a show of strength. | 0:14:33 | 0:14:37 | |
'Each male competes to churn up the biggest dust cloud | 0:14:43 | 0:14:47 | |
'and intimidate its rivals. | 0:14:47 | 0:14:49 | |
'But when two heavyweights won't back down, they go head-to-head. | 0:14:53 | 0:14:58 | |
Heavily-muscled necks and thick skulls covered in a mat of | 0:15:03 | 0:15:07 | |
dense hair help absorb the colossal forces of each collision. | 0:15:07 | 0:15:12 | |
Only the winner earns the right to mate. | 0:15:16 | 0:15:20 | |
This ensures the strongest genes will be passed on. | 0:15:28 | 0:15:33 | |
Whilst I've been following herds of prey animals on the plateau... | 0:15:37 | 0:15:41 | |
..our camera crews are at lower altitudes on the trail of | 0:15:43 | 0:15:46 | |
Yellowstone's top predator, the wolf. | 0:15:46 | 0:15:50 | |
Over 500 wolves roam across Greater Yellowstone. | 0:15:53 | 0:15:58 | |
The mild winter and spring caused many packs to go hungry | 0:15:58 | 0:16:02 | |
as the prey was well fed and could outrun the wolves. | 0:16:02 | 0:16:06 | |
In summer, the stakes are even higher because there are young pups | 0:16:08 | 0:16:13 | |
to feed. | 0:16:13 | 0:16:14 | |
In the south of Greater Yellowstone, | 0:16:17 | 0:16:19 | |
biologists have been studying one wolf pack that seems to be defying | 0:16:19 | 0:16:24 | |
the odds and thriving this year - | 0:16:24 | 0:16:26 | |
the Pinnacle Peak pack. | 0:16:26 | 0:16:28 | |
This photo was taken during an aerial survey. | 0:16:30 | 0:16:33 | |
It reveals the pack has 11 pups. | 0:16:33 | 0:16:36 | |
Unusually, two females have given birth this year - | 0:16:36 | 0:16:41 | |
a sign this pack is doing well. | 0:16:41 | 0:16:43 | |
All the adults take it in turns to hunt and return to the den sites | 0:16:45 | 0:16:49 | |
with meat for the pups. | 0:16:49 | 0:16:51 | |
But the elk that make up the majority of wolves' prey have moved | 0:16:51 | 0:16:55 | |
to higher grazing grounds. | 0:16:55 | 0:16:57 | |
The biologists have been observing how the pack finds enough food | 0:17:01 | 0:17:05 | |
for all 11 pups. They've directed wildlife cameraman | 0:17:05 | 0:17:09 | |
Charlie Hamilton James to an area where they've seen | 0:17:09 | 0:17:13 | |
remarkable behaviour. | 0:17:13 | 0:17:14 | |
They think the key to the wolves' success here could be down | 0:17:16 | 0:17:20 | |
to human activity. | 0:17:20 | 0:17:21 | |
See it? | 0:17:36 | 0:17:37 | |
I wonder if | 0:17:45 | 0:17:46 | |
she's going to let me get out. | 0:17:46 | 0:17:48 | |
I'm going to give it a go. | 0:17:49 | 0:17:50 | |
Bear with me on this. | 0:17:52 | 0:17:53 | |
-WHISPERS: -Well, well, well, well, well! | 0:18:17 | 0:18:20 | |
How beautiful is that? | 0:18:30 | 0:18:32 | |
She can smell me. My scent is going straight ahead. | 0:18:32 | 0:18:36 | |
She knows I'm here. | 0:18:36 | 0:18:37 | |
She's not bothered at all. | 0:18:38 | 0:18:40 | |
In all his 20 years of filming, | 0:18:43 | 0:18:45 | |
Charlie has never been this close to a wild wolf. | 0:18:45 | 0:18:49 | |
This female is from the Pinnacle Peak pack. | 0:18:53 | 0:18:56 | |
And something has drawn her here. | 0:19:00 | 0:19:01 | |
The grass is still green | 0:19:06 | 0:19:08 | |
because it's been watered over the summer to improve grazing. | 0:19:08 | 0:19:12 | |
You can see all these sprinklers behind her. | 0:19:21 | 0:19:22 | |
Cos they're watering the grass, | 0:19:22 | 0:19:25 | |
it's created some amazing habitat for ground squirrels. | 0:19:25 | 0:19:27 | |
There's just tonnes of them. | 0:19:27 | 0:19:29 | |
A huge colony of grass-eating | 0:19:36 | 0:19:38 | |
Uinta ground squirrels is exploiting this artificial oasis. | 0:19:38 | 0:19:42 | |
Usually, by mid-July, the grass would be turning brown and inedible. | 0:19:45 | 0:19:49 | |
The squirrels would have started entering their burrows to hibernate, | 0:19:50 | 0:19:54 | |
but not here. | 0:19:54 | 0:19:55 | |
This female wolf has spotted the chance of an easy meal. | 0:19:58 | 0:20:02 | |
And it's closer to the pups than the large elk herds 20 miles away. | 0:20:05 | 0:20:09 | |
They need these ground squirrels cos they're tied to their territory. | 0:20:19 | 0:20:22 | |
They've got pups here, they can't go anywhere else, | 0:20:22 | 0:20:24 | |
so they have to find food around here... | 0:20:24 | 0:20:26 | |
..just to survive and keep those pups alive. | 0:20:27 | 0:20:29 | |
But catching these burrowing rodents is tricky. | 0:20:32 | 0:20:36 | |
They spend much of their time looking for danger, | 0:20:39 | 0:20:43 | |
balancing on their hind legs to see over the tall grass. | 0:20:43 | 0:20:47 | |
The squirrels also have a range of alarm calls for different threats. | 0:20:53 | 0:20:58 | |
SQUIRREL TRILLS | 0:21:04 | 0:21:06 | |
A trill means it's a ground-based predator. | 0:21:07 | 0:21:11 | |
SQUIRREL TRILLS | 0:21:11 | 0:21:13 | |
The entire colony dive for the safety of their burrows. | 0:21:15 | 0:21:19 | |
Look at that! She's on it. She's on one. She's on one. Oh! | 0:21:25 | 0:21:28 | |
This female is putting in a lot of work but without any reward. | 0:21:33 | 0:21:37 | |
Oh, there's another one. There we go! There's one running. | 0:21:41 | 0:21:44 | |
Ah! Where is it? Where is it? Where is it? | 0:21:44 | 0:21:45 | |
A long way off. | 0:21:45 | 0:21:46 | |
Another pack member may help turn the tables. | 0:21:54 | 0:21:58 | |
Wolves' real strength is when they hunt together. | 0:21:58 | 0:22:01 | |
There's another one. | 0:22:15 | 0:22:16 | |
There's another wolf! | 0:22:19 | 0:22:21 | |
I don't know which one to film now. | 0:22:33 | 0:22:35 | |
SQUIRRELS TRILL | 0:22:36 | 0:22:39 | |
The ground squirrels can't watch all three wolves at once. | 0:22:40 | 0:22:43 | |
And these newcomers are also trying a different hunting strategy | 0:22:48 | 0:22:53 | |
to outwit their quarry. | 0:22:53 | 0:22:55 | |
SQUIRREL SQUEAKS | 0:22:56 | 0:22:57 | |
There's a lot of activity and then they'll lie down. | 0:23:03 | 0:23:07 | |
And you think, well, why are they suddenly lying down? | 0:23:07 | 0:23:10 | |
Part of their hunting strategy is to lie down | 0:23:14 | 0:23:17 | |
and essentially just wait for the ground squirrels to come up to them, | 0:23:17 | 0:23:21 | |
you know, and they're sort of dozing and they're half asleep, and | 0:23:21 | 0:23:23 | |
a ground squirrel comes up and they just leap up and grab it. | 0:23:23 | 0:23:25 | |
It's working. | 0:23:35 | 0:23:36 | |
Even the original female is having more luck. | 0:23:39 | 0:23:42 | |
With animals, you get these peak moments of activity and they last | 0:23:53 | 0:23:58 | |
for a few days or a few weeks and then they're gone again. | 0:23:58 | 0:24:01 | |
It's incredibly lucky that we've been able to be here for this | 0:24:02 | 0:24:07 | |
particular period of peak activity. | 0:24:07 | 0:24:09 | |
I've never seen it before, I don't know if it'll ever happen again, | 0:24:09 | 0:24:12 | |
but it's amazing to witness it. | 0:24:12 | 0:24:14 | |
These wolves have used all their intelligence to exploit this situation. | 0:24:21 | 0:24:26 | |
The food will increase the pups' chance of survival. | 0:24:35 | 0:24:39 | |
And more wolves means a stronger pack next year. | 0:24:51 | 0:24:55 | |
It's early July and no rain has fallen this month | 0:25:08 | 0:25:11 | |
at the Snake River, where the beavers have their home. | 0:25:11 | 0:25:14 | |
This, combined with the early snow melt, | 0:25:16 | 0:25:19 | |
means that the river is running 20% below its average. | 0:25:19 | 0:25:22 | |
If the level of the beavers' main pond drops too low, it could expose | 0:25:25 | 0:25:29 | |
the entrance to their lodge, which is usually underwater. | 0:25:29 | 0:25:32 | |
And this would make them easy pickings for predators. | 0:25:32 | 0:25:35 | |
Jeff is watching them closely to see how they react. | 0:25:40 | 0:25:43 | |
Oh, look! Wow! | 0:25:45 | 0:25:48 | |
That's Mum. | 0:25:48 | 0:25:49 | |
And it looks like Mum has made an executive decision. | 0:25:50 | 0:25:54 | |
She's got one of the kits in her mouth. | 0:25:54 | 0:25:57 | |
She's heading towards the dam. | 0:25:57 | 0:25:59 | |
She's moving one of her kits out of the pond, | 0:25:59 | 0:26:01 | |
maybe to search for a new home. | 0:26:01 | 0:26:03 | |
This is incredible! | 0:26:10 | 0:26:11 | |
And there they go. | 0:26:17 | 0:26:18 | |
I'm going to go chase them. | 0:26:18 | 0:26:20 | |
Scientists have observed beaver families relocating, | 0:26:23 | 0:26:26 | |
but Jeff has never witnessed it in 20 years of studying them. | 0:26:26 | 0:26:31 | |
Out in the open, kits are vulnerable to predators like bald eagles. | 0:26:31 | 0:26:36 | |
It's a tense moment for Mum and her young. | 0:26:36 | 0:26:38 | |
Here they come. | 0:26:46 | 0:26:47 | |
The beaver family's territory is large, | 0:26:49 | 0:26:51 | |
with five dams and pools along this river. | 0:26:51 | 0:26:55 | |
She's going to crawl over this next dam. | 0:26:55 | 0:26:57 | |
After travelling more than 350 metres... | 0:27:14 | 0:27:17 | |
..and crossing three more dams... | 0:27:19 | 0:27:20 | |
..Jeff films the mum leading her kit up a small channel that comes off | 0:27:22 | 0:27:27 | |
the main river. | 0:27:27 | 0:27:29 | |
They're going to climb right up through this cascading stream... | 0:27:29 | 0:27:33 | |
..waddling up through the stones. | 0:27:34 | 0:27:35 | |
You can see that the beavers don't do quite so well on land, | 0:27:35 | 0:27:38 | |
especially with this river rock. | 0:27:38 | 0:27:41 | |
They do so much better in the water. | 0:27:41 | 0:27:43 | |
Unreal! | 0:27:45 | 0:27:47 | |
Never seen this, ever! | 0:27:47 | 0:27:49 | |
And there they go. | 0:27:51 | 0:27:52 | |
Later, at night, Jeff checks his camera in the lodge. | 0:27:55 | 0:28:00 | |
Let's see. | 0:28:00 | 0:28:01 | |
It reveals Mum has moved all the kits and the whole family has | 0:28:08 | 0:28:13 | |
abandoned their home. | 0:28:13 | 0:28:14 | |
Jeff is now on a mission to find out where the beavers have gone... | 0:28:19 | 0:28:23 | |
..if the kits survive and whether this huge gamble will pay off. | 0:28:24 | 0:28:28 | |
Whilst the low-lying rivers and grasslands are sweltering | 0:28:33 | 0:28:37 | |
in temperatures of nearly 30 degrees... | 0:28:37 | 0:28:39 | |
..2,000 metres up, Yellowstone peaks have a recent dusting of fresh snow. | 0:28:40 | 0:28:45 | |
And the mountain meadows are a riot of colour. | 0:28:48 | 0:28:51 | |
It is amazing, the contrast up here to down in the valley. | 0:29:03 | 0:29:08 | |
Down in the valley, summer has really taken grip - | 0:29:08 | 0:29:11 | |
the temperatures are quite high and the grass is starting to go brown. | 0:29:11 | 0:29:15 | |
But up here, 800 metres higher, it's a totally different story. | 0:29:15 | 0:29:20 | |
It's breezy, it's cool, and look at all these magnificent wild flowers! | 0:29:20 | 0:29:25 | |
Susan Marsh is a naturalist and she pays very close attention to these | 0:29:37 | 0:29:41 | |
high-altitude wild flowers. | 0:29:41 | 0:29:44 | |
Where most people see pretty petals, | 0:29:46 | 0:29:48 | |
Susan sees a living record of how this ecosystem is being affected | 0:29:48 | 0:29:54 | |
by this year's weather and the changing climate. | 0:29:54 | 0:29:57 | |
We've looked a lot at how animals can indicate | 0:30:00 | 0:30:04 | |
the state of how a year is progressing, | 0:30:04 | 0:30:06 | |
as far as the weather is concerned. | 0:30:06 | 0:30:08 | |
Are the plants just as valuable as indicators? | 0:30:08 | 0:30:11 | |
Yes. I think they are | 0:30:11 | 0:30:12 | |
and the one advantage | 0:30:12 | 0:30:14 | |
that they have, in my opinion, | 0:30:14 | 0:30:15 | |
is that they don't run off! | 0:30:15 | 0:30:17 | |
And they don't fly away. | 0:30:17 | 0:30:18 | |
-Very true. -I can tell by how tall they are, first of all. | 0:30:18 | 0:30:22 | |
-Right. -This one is fireweed. | 0:30:22 | 0:30:25 | |
And it, typically, in a really lush year, will grow head high. | 0:30:25 | 0:30:30 | |
-Wow! -Even at this elevation. | 0:30:30 | 0:30:32 | |
These particular ones, you can see, are only a couple of feet tall. | 0:30:32 | 0:30:36 | |
-Yeah, yeah. -To me that's an indication of heat and dryness. | 0:30:36 | 0:30:41 | |
The plant needs to set seed and it has a very short growing season, | 0:30:41 | 0:30:45 | |
so it's not going to waste its energy making a big, tall stalk, | 0:30:45 | 0:30:49 | |
or making great big leaves. | 0:30:49 | 0:30:51 | |
-Right. -These leaves are small this year, smaller than usual. | 0:30:51 | 0:30:54 | |
Through these plants, Susan can chart this year's erratic weather | 0:30:57 | 0:31:02 | |
but can plants also indicate larger changes? | 0:31:02 | 0:31:06 | |
Everyone is talking about the fact that the climate is changing. | 0:31:07 | 0:31:11 | |
Is that something that is becoming evident in the plants? | 0:31:11 | 0:31:15 | |
It's typically on the mountain tops. | 0:31:15 | 0:31:17 | |
So that's above the tree line. | 0:31:17 | 0:31:18 | |
Above the trees, where there's rocks and wind and cold. | 0:31:18 | 0:31:24 | |
It's the coldest part of Yellowstone, above 3,000 metres, | 0:31:28 | 0:31:33 | |
where Susan is seeing the effects of climate change hit hard. | 0:31:33 | 0:31:37 | |
This is the alpine zone, a realm of high-altitude specialists. | 0:31:41 | 0:31:46 | |
But as temperatures keep getting warmer, | 0:31:48 | 0:31:51 | |
non-specialist plants are able to survive higher up the mountains | 0:31:51 | 0:31:56 | |
and they're invading this fragile zone. | 0:31:56 | 0:31:59 | |
Does it concern you that you are seeing | 0:32:02 | 0:32:05 | |
a march towards a very different climate | 0:32:05 | 0:32:08 | |
and, therefore, a very different ecosystem? | 0:32:08 | 0:32:12 | |
I think there will be some good and some bad, | 0:32:12 | 0:32:14 | |
depending on what species you are, as climate change continues. | 0:32:14 | 0:32:17 | |
But, yes, I don't want to lose the wildflower parts that I love. | 0:32:17 | 0:32:21 | |
I don't want to lose the alpine zone. | 0:32:21 | 0:32:23 | |
I don't want to see those go, | 0:32:25 | 0:32:26 | |
but I don't think I can stop it. | 0:32:26 | 0:32:29 | |
Climatologists studying Greater Yellowstone | 0:32:34 | 0:32:37 | |
have charted temperatures increasing | 0:32:37 | 0:32:39 | |
by nearly a fifth of a degree every decade. | 0:32:39 | 0:32:42 | |
This seemingly small change is having far-reaching consequences. | 0:32:43 | 0:32:48 | |
Across Yellowstone, | 0:32:49 | 0:32:50 | |
scientists are seeing how animals are being forced to adapt. | 0:32:50 | 0:32:54 | |
Even the most iconic species like the grizzly bear are being affected. | 0:32:58 | 0:33:03 | |
To find out what's going on, | 0:33:05 | 0:33:07 | |
Patrick has gone to the Gallatin mountain range | 0:33:07 | 0:33:10 | |
in the north-west of Greater Yellowstone. | 0:33:10 | 0:33:12 | |
I've come to meet our bear expert, Casey Anderson, | 0:33:16 | 0:33:19 | |
to see how one group of grizzly bears is coping, | 0:33:19 | 0:33:23 | |
as the changing climate threatens an important food source. | 0:33:23 | 0:33:26 | |
If you look up at this knob up here, | 0:33:29 | 0:33:31 | |
take a look at the trees just around the bottom of that. | 0:33:31 | 0:33:34 | |
Those are white bark pines. | 0:33:34 | 0:33:35 | |
Let's have a look. | 0:33:35 | 0:33:36 | |
That entire forest of white bark pine, ancient trees, | 0:33:40 | 0:33:43 | |
some of them are 300 years old, | 0:33:43 | 0:33:45 | |
they've all died in the last couple of years. | 0:33:45 | 0:33:48 | |
They're gone. | 0:33:48 | 0:33:49 | |
What's caused it to die off? | 0:33:51 | 0:33:54 | |
There's a pine beetle that's always existed up there, | 0:33:54 | 0:33:56 | |
but we've had these cold winters | 0:33:56 | 0:33:59 | |
that usually just killed most of the beetles, | 0:33:59 | 0:34:01 | |
but now, with climate change, those winters are not as harsh, | 0:34:01 | 0:34:04 | |
we're not having that beetle kill | 0:34:04 | 0:34:07 | |
that we're used to in the middle of the winter, | 0:34:07 | 0:34:09 | |
so the beetles are really starting to infest the forest. | 0:34:09 | 0:34:12 | |
Pine beetles are no bigger than grains of rice | 0:34:13 | 0:34:17 | |
but these small creatures cause big problems. | 0:34:17 | 0:34:21 | |
Not only do their young eat the trees' living tissue, | 0:34:21 | 0:34:24 | |
but they also introduce a destructive fungus. | 0:34:24 | 0:34:27 | |
Eventually, this combination kills the entire tree. | 0:34:27 | 0:34:32 | |
This is bad news for the animals | 0:34:32 | 0:34:34 | |
that rely upon the food and shelter this tree provides. | 0:34:34 | 0:34:38 | |
Towards the end of summer, as other food sources dry up, | 0:34:42 | 0:34:45 | |
these pine nuts usually provide vital protein for grizzlies. | 0:34:45 | 0:34:49 | |
One aerial survey revealed around 80% of mature white barked trees in | 0:34:56 | 0:35:00 | |
Greater Yellowstone show signs | 0:35:00 | 0:35:03 | |
of moderate-to-severe beetle infestation. | 0:35:03 | 0:35:06 | |
To survive, the bears must adapt | 0:35:06 | 0:35:09 | |
and Casey has witnessed some intriguing behaviour. | 0:35:10 | 0:35:14 | |
Grizzlies are leaving the wilderness | 0:35:16 | 0:35:19 | |
to congregate on this cattle ranch to feed. | 0:35:19 | 0:35:21 | |
What they are eating is this caraway root | 0:35:27 | 0:35:29 | |
that actually came in with livestock. | 0:35:29 | 0:35:31 | |
It's actually an introduced species not native to the area | 0:35:31 | 0:35:34 | |
and they're coming down here and taking advantage of it. | 0:35:34 | 0:35:36 | |
And all the bears in the area are starting to migrate towards this meadow | 0:35:38 | 0:35:41 | |
because there's not a lot of food out there in the summer but, | 0:35:41 | 0:35:44 | |
right here, this is like a bear buffet! | 0:35:44 | 0:35:47 | |
It's a race against time. | 0:35:47 | 0:35:48 | |
The bears must pile on enough fat | 0:35:48 | 0:35:51 | |
to see them through five months of hibernation. | 0:35:51 | 0:35:55 | |
While the root is at its most abundant in summer and autumn, | 0:35:55 | 0:35:58 | |
the grizzlies gorge throughout the night, | 0:35:58 | 0:36:01 | |
eating up to 20,000 calories in a single sitting. | 0:36:01 | 0:36:05 | |
As the day heats up, | 0:36:14 | 0:36:16 | |
the hot sun forces them back into the shady forest to rest. | 0:36:17 | 0:36:21 | |
But Casey and our mobile camera team | 0:36:26 | 0:36:28 | |
have seen two bears that are still out in the midday sun. | 0:36:30 | 0:36:34 | |
Hey, Casey, do you copy? | 0:36:36 | 0:36:37 | |
They're, like, totally tumbling around out there. | 0:36:41 | 0:36:44 | |
Well, they're little playful guys! | 0:36:46 | 0:36:50 | |
These two yearlings are orphans. | 0:37:00 | 0:37:02 | |
Unfortunately, their mum died last autumn but, | 0:37:02 | 0:37:05 | |
against the odds, they have turned up in this meadow. | 0:37:05 | 0:37:09 | |
I've joined Casey to see how they're doing. | 0:37:10 | 0:37:12 | |
Right here, there's two yearling grizzly cubs, | 0:37:13 | 0:37:17 | |
right out here, digging around. | 0:37:17 | 0:37:19 | |
Oh, yeah, right there. | 0:37:19 | 0:37:21 | |
They're still young and inexperienced. | 0:37:25 | 0:37:27 | |
Cubs usually stay with their mums for up to three and a half years | 0:37:28 | 0:37:32 | |
but, even with this protection, | 0:37:32 | 0:37:34 | |
almost a third won't survive in Yellowstone. | 0:37:34 | 0:37:37 | |
It's a miracle that these two | 0:37:39 | 0:37:41 | |
made it through an entire winter on their own. | 0:37:41 | 0:37:44 | |
Do you think that having one another | 0:37:51 | 0:37:53 | |
is one of the reasons why they've made it this far? | 0:37:53 | 0:37:57 | |
I think it's got to be one of the biggest reasons. | 0:37:57 | 0:38:00 | |
If they didn't have each other, I don't think there's any chance | 0:38:02 | 0:38:06 | |
that one of them would have survived. | 0:38:06 | 0:38:08 | |
They've got each other's back. | 0:38:08 | 0:38:10 | |
Whilst feeding on this working ranch, | 0:38:14 | 0:38:16 | |
there are lots of unusual sights and sounds. | 0:38:16 | 0:38:19 | |
But without a mum to teach them, | 0:38:26 | 0:38:28 | |
it's hard for the cubs to know what is and isn't dangerous. | 0:38:28 | 0:38:32 | |
You find yourself really worrying about them | 0:38:36 | 0:38:38 | |
because they don't have | 0:38:40 | 0:38:42 | |
that notorious Mama Grizzly looking out for them. | 0:38:42 | 0:38:44 | |
Yeah, they're looking a little bit nervous. | 0:38:53 | 0:38:55 | |
So they're looking at something over in the distance. | 0:38:55 | 0:38:58 | |
They've obviously sensed something in that direction. | 0:39:02 | 0:39:05 | |
I think that these two have probably been chased, | 0:39:05 | 0:39:07 | |
probably once a day, by something, whether it's another grizzly, | 0:39:07 | 0:39:11 | |
a pack of wolves, or even cattle. | 0:39:11 | 0:39:13 | |
Surprisingly, the dangers may not come from the ranchers | 0:39:20 | 0:39:23 | |
or their cattle. | 0:39:23 | 0:39:24 | |
Most have learned to live alongside their grizzly neighbours. | 0:39:26 | 0:39:29 | |
One of the biggest threats comes in the form of other bears | 0:39:31 | 0:39:35 | |
close by in the shade of the forests. | 0:39:35 | 0:39:38 | |
A big male grizzly, known as a boar, could kill and eat the cubs | 0:39:42 | 0:39:47 | |
but it looks like these two have found a way to avoid this danger. | 0:39:47 | 0:39:51 | |
The big boars and other bears are out at night | 0:39:51 | 0:39:54 | |
because when it's hot, like this, | 0:39:54 | 0:39:55 | |
most bears will not come out and dig, | 0:39:55 | 0:39:57 | |
because it just wears them out. | 0:39:57 | 0:39:59 | |
And as the sun comes up, they go back to the forest. | 0:40:00 | 0:40:03 | |
With these little guys, they're kind of on the opposite schedule. | 0:40:03 | 0:40:06 | |
When the danger goes away, it's time to eat. | 0:40:06 | 0:40:09 | |
Let's do it in the heat of the day when there's nobody else out here. | 0:40:11 | 0:40:15 | |
Where you don't have to worry about anything. | 0:40:15 | 0:40:17 | |
That's what they're doing and it's working for them. | 0:40:17 | 0:40:20 | |
It's an amazing strategy. | 0:40:20 | 0:40:22 | |
The two cubs are a fantastic indicator | 0:40:25 | 0:40:27 | |
of just how intelligent bears can be. | 0:40:27 | 0:40:30 | |
Even as climate change kills off the white bark pine, | 0:40:32 | 0:40:35 | |
the bears are adapting to exploit the opportunities. | 0:40:35 | 0:40:39 | |
With over 700 grizzlies in Greater Yellowstone, | 0:40:40 | 0:40:44 | |
the latest data suggests their population, for now, at least, | 0:40:44 | 0:40:48 | |
has remained stable. | 0:40:48 | 0:40:49 | |
Yellowstone hasn't reached its record temperature of 36 degrees | 0:40:58 | 0:41:03 | |
but climate data has revealed that July, this year, | 0:41:05 | 0:41:09 | |
was the seventh month in a row with above average temperatures. | 0:41:09 | 0:41:13 | |
The relentless heat | 0:41:20 | 0:41:23 | |
and the early thaw are a dangerous combination. | 0:41:23 | 0:41:26 | |
They may create perfect conditions... | 0:41:29 | 0:41:32 | |
..for wildfires. | 0:41:34 | 0:41:36 | |
In normal years, the snowmelt would come down off the mountains, | 0:41:39 | 0:41:43 | |
and it would hang around places, like this, | 0:41:43 | 0:41:45 | |
soaking into all this dead wood, but not this year. | 0:41:45 | 0:41:48 | |
What it did was come rushing off in a great torrent | 0:41:48 | 0:41:51 | |
into the rivers, into the streams, into the lakes | 0:41:51 | 0:41:53 | |
and it didn't have time to soak into all of this dead, dry wood. | 0:41:53 | 0:41:58 | |
So this is, basically, fuel for fires | 0:41:58 | 0:42:02 | |
and having so much dead, dry wood around | 0:42:02 | 0:42:05 | |
means that there is a danger this year | 0:42:05 | 0:42:08 | |
of bigger and more intense fires. | 0:42:08 | 0:42:10 | |
A single spark could set this landscape alight. | 0:42:12 | 0:42:16 | |
Every summer, an average of 26 wildfires | 0:42:18 | 0:42:21 | |
are started by lightning across Yellowstone National Park. | 0:42:21 | 0:42:24 | |
Our crews are out, following up on reports of wildfire. | 0:42:30 | 0:42:34 | |
Flames can reach heights of 50 metres, exceed 1,200 Celsius, | 0:42:35 | 0:42:41 | |
and rip through the landscape at up to 40mph. | 0:42:41 | 0:42:45 | |
By mid-August, the tinder-dry conditions | 0:42:45 | 0:42:48 | |
mean five major fires have taken hold, | 0:42:48 | 0:42:51 | |
and are raging across the region. | 0:42:51 | 0:42:54 | |
In the Beartooth Mountains is wildlife cameraman Jeff Hogan. | 0:42:56 | 0:43:01 | |
Oh, no, this is nuts! | 0:43:02 | 0:43:03 | |
He's filming a wildfire that's consuming a huge area of forest. | 0:43:04 | 0:43:08 | |
And it's headed straight towards the family of great grey owls | 0:43:09 | 0:43:12 | |
he's been following since spring. | 0:43:12 | 0:43:14 | |
This fire is huge, and it's raging. | 0:43:24 | 0:43:26 | |
It's right in the backyard of our great grey owl family. | 0:43:26 | 0:43:30 | |
This is really a threat. | 0:43:30 | 0:43:31 | |
So far, the chicks have done much better than expected. | 0:43:38 | 0:43:41 | |
There was only a 20% chance all three would make it out of the nest. | 0:43:44 | 0:43:48 | |
Oh, he's going to go, he's going to go. | 0:43:48 | 0:43:51 | |
Jump, jump! | 0:43:51 | 0:43:53 | |
Oh, wow! | 0:43:55 | 0:43:56 | |
Jeff thought their biggest challenges were over. | 0:43:57 | 0:44:00 | |
But now, he'll have to wait until the fire's died down | 0:44:08 | 0:44:11 | |
to see if these young owls survive. | 0:44:11 | 0:44:13 | |
Oh, my goodness. | 0:44:18 | 0:44:19 | |
The aftermath of a fire might seem devastating, | 0:44:21 | 0:44:24 | |
but it's actually part of the forest's natural cycle. | 0:44:24 | 0:44:27 | |
It brings growth and new life. | 0:44:27 | 0:44:30 | |
All this ash is actually really fertile | 0:44:30 | 0:44:34 | |
and as soon as it rains, | 0:44:34 | 0:44:36 | |
new green shoots are going to start popping up, | 0:44:36 | 0:44:39 | |
and that's going to encourage grazers like elk and deer | 0:44:39 | 0:44:42 | |
to come into this area and, eventually, grizzly bears. | 0:44:42 | 0:44:46 | |
But not only that, some plants have actually evolved | 0:44:46 | 0:44:50 | |
to benefit from fires. These here are lodgepole pine cones | 0:44:50 | 0:44:55 | |
and they only open up once they reach a specific temperature | 0:44:55 | 0:44:59 | |
that can only be produced by a fire | 0:44:59 | 0:45:02 | |
and then these seeds will eventually fall off, | 0:45:02 | 0:45:05 | |
down into the ground | 0:45:05 | 0:45:07 | |
and be fertilised by the ash. | 0:45:07 | 0:45:09 | |
Fires are a natural part of life here. | 0:45:12 | 0:45:15 | |
But by the time they die down, | 0:45:15 | 0:45:18 | |
they will have burnt nearly 100 square miles of land. | 0:45:18 | 0:45:21 | |
This year's fires will have been the most destructive | 0:45:23 | 0:45:26 | |
inside Yellowstone National Park since 1988. | 0:45:26 | 0:45:30 | |
Large-scale fires used to sweep through the park | 0:45:30 | 0:45:33 | |
around every 300 years. | 0:45:33 | 0:45:35 | |
But scientists now believe that the warming climate could result | 0:45:35 | 0:45:40 | |
in them happening every 3-5 years by the end of this century. | 0:45:40 | 0:45:44 | |
This could result in the destruction of the forest | 0:45:46 | 0:45:49 | |
that's home to the fragile population of great grey owls. | 0:45:49 | 0:45:53 | |
Jeff is searching the area at the edge of the burn | 0:45:57 | 0:46:01 | |
for any sign of the owl family. | 0:46:01 | 0:46:03 | |
There's a lot of ground to cover | 0:46:08 | 0:46:11 | |
so Jeff calls in expert animal tracker Dan Hartman. | 0:46:11 | 0:46:15 | |
After four days' searching, | 0:46:16 | 0:46:19 | |
Dan finally hears an adult great grey. | 0:46:19 | 0:46:24 | |
OWL CALLS | 0:46:26 | 0:46:28 | |
And close by, one of the young owls. | 0:46:32 | 0:46:35 | |
OWL CALLS CONTINUE | 0:46:37 | 0:46:40 | |
After another few minutes watching and listening, | 0:46:45 | 0:46:49 | |
he spots the other two siblings. | 0:46:49 | 0:46:51 | |
All of them have survived. | 0:47:04 | 0:47:06 | |
And they're even making their first attempt at hunting. | 0:47:10 | 0:47:14 | |
The owl chicks have all made it through their first summer, | 0:47:22 | 0:47:26 | |
but we still don't know the fate of the beaver mum and her three kits. | 0:47:26 | 0:47:31 | |
I've joined Jeff on a tributary of the Snake River, | 0:47:35 | 0:47:38 | |
where he's seen signs that the beavers are making a new home. | 0:47:38 | 0:47:43 | |
He thinks it's a safer location, | 0:47:44 | 0:47:46 | |
as the water level is higher than at their old pond. | 0:47:46 | 0:47:50 | |
Oh, look. | 0:48:07 | 0:48:09 | |
There's your beaver sitting there. | 0:48:12 | 0:48:14 | |
Oh, my... Is it that beaver there? | 0:48:14 | 0:48:16 | |
That's the beaver, right there. | 0:48:16 | 0:48:18 | |
This is just gold dust. | 0:48:18 | 0:48:21 | |
This looks like Mum. | 0:48:23 | 0:48:25 | |
And in the few weeks since moving, the family has been busy building. | 0:48:25 | 0:48:29 | |
That is a new lodge being built right now. | 0:48:34 | 0:48:36 | |
They just make a big pile of sticks, | 0:48:36 | 0:48:39 | |
then they go into it and start digging it up | 0:48:39 | 0:48:42 | |
and they'll pile mud and stuff up on top of it. | 0:48:42 | 0:48:43 | |
This is a lodge at its early stages. | 0:48:45 | 0:48:49 | |
This is rare. | 0:48:49 | 0:48:50 | |
Rarely do you see the very early stages of a whole new beaver pond | 0:48:50 | 0:48:55 | |
with a lodge like this. | 0:48:55 | 0:48:57 | |
They're concentrating on their dam, | 0:49:01 | 0:49:03 | |
strengthening it with rocks and plugging any leaks | 0:49:03 | 0:49:07 | |
with weeds and mud to create a deep, wide pond. | 0:49:07 | 0:49:10 | |
The water table here is rising so that they can reach out | 0:49:12 | 0:49:16 | |
and get more of this food, the trees that grow around here, | 0:49:16 | 0:49:18 | |
cotton woods, alders, willows. | 0:49:18 | 0:49:21 | |
The beavers can now access all this untapped food... | 0:49:21 | 0:49:25 | |
..without having to venture far onto dry land, where they are vulnerable. | 0:49:27 | 0:49:30 | |
'Finally, Jeff spots what we've both been hoping to see.' | 0:49:36 | 0:49:41 | |
-Oh, yeah. -There's a young one. | 0:49:41 | 0:49:43 | |
-There's the young one. -Yes, yes. | 0:49:43 | 0:49:45 | |
We've got our three young beavers right here, the three kits. | 0:50:00 | 0:50:04 | |
-They're getting big. -They are. | 0:50:07 | 0:50:09 | |
They're getting big fast. | 0:50:09 | 0:50:10 | |
Mum's risky gamble appears to have paid off. | 0:50:13 | 0:50:17 | |
This deep pond with a new lodge and plenty of food | 0:50:18 | 0:50:22 | |
is everything the kits will need to thrive. | 0:50:22 | 0:50:25 | |
They are so inquisitive, aren't they? | 0:50:27 | 0:50:30 | |
And they're just... | 0:50:32 | 0:50:33 | |
They're just fabulous to watch. | 0:50:33 | 0:50:36 | |
The kits will stay with their parents for the next two years. | 0:50:44 | 0:50:47 | |
In that time, they'll learn the engineering skills needed | 0:50:47 | 0:50:51 | |
to build a dam and a lodge. | 0:50:51 | 0:50:54 | |
The secret to the beavers' success | 0:50:55 | 0:50:57 | |
is adapting the landscape to suit their needs. | 0:50:57 | 0:51:01 | |
It's engineering on a scale that has only been surpassed by humans. | 0:51:04 | 0:51:09 | |
Every year, the challenges in Yellowstone are getting greater, | 0:51:18 | 0:51:22 | |
as climate change results in more extreme weather. | 0:51:22 | 0:51:26 | |
Yellowstone's residents have developed | 0:51:26 | 0:51:29 | |
clever strategies to survive. | 0:51:29 | 0:51:31 | |
But the last animal I want to see | 0:51:31 | 0:51:33 | |
is quickly running out of options as temperatures rise. | 0:51:33 | 0:51:38 | |
I've come up to 3,000 metres and the fragile alpine zone. | 0:51:41 | 0:51:46 | |
Only one specialist mammal is active up here all year round - | 0:51:50 | 0:51:56 | |
the pika. | 0:51:56 | 0:51:57 | |
And Kaitlyn Hanley is the hardy researcher who studies them. | 0:52:04 | 0:52:09 | |
I've got glimpses of pika. | 0:52:13 | 0:52:16 | |
Are they a member of the rabbit family? | 0:52:16 | 0:52:18 | |
They call them rock rabbits. | 0:52:18 | 0:52:19 | |
-SQUEAKING -Oh, there was one. -A little call? | 0:52:19 | 0:52:21 | |
Yeah, that was a pika. | 0:52:21 | 0:52:23 | |
Come on, Kaitlyn. | 0:52:23 | 0:52:25 | |
-I want you to... -He's right there. | 0:52:25 | 0:52:26 | |
Oh, my goodness, there he is! | 0:52:26 | 0:52:29 | |
Pikas are thought to have evolved from ancestors in Siberia - | 0:52:41 | 0:52:45 | |
one of the coldest places on Earth. | 0:52:45 | 0:52:48 | |
Their odd appearance is all about keeping warm. | 0:52:53 | 0:52:57 | |
A plump, round shape minimises surface heat loss | 0:52:59 | 0:53:03 | |
and thick fur covers their entire bodies, | 0:53:03 | 0:53:07 | |
even their toes. | 0:53:07 | 0:53:11 | |
For pikas, summer is all about collecting food. | 0:53:13 | 0:53:16 | |
I imagine that up here, | 0:53:20 | 0:53:22 | |
the season where there is any food at all is pretty short. | 0:53:22 | 0:53:25 | |
Yes, and they don't hibernate in the winter | 0:53:25 | 0:53:28 | |
so they actually collect hay through the entire summer. | 0:53:28 | 0:53:31 | |
And they'll use that as their food source during the winter. | 0:53:32 | 0:53:35 | |
-So that's what they're doing now? -Yes, they are haying, yes. | 0:53:35 | 0:53:37 | |
They'll get these huge hay piles under the rocks | 0:53:39 | 0:53:41 | |
and they'll use that in the winter. | 0:53:41 | 0:53:43 | |
And, yeah, they're the only mammal that doesn't hibernate up this high. | 0:53:43 | 0:53:47 | |
And they can survive? | 0:53:51 | 0:53:52 | |
Cos the snow must come here, what, in October? | 0:53:52 | 0:53:55 | |
Yeah, so it would be October... | 0:53:55 | 0:53:57 | |
Through to? | 0:53:57 | 0:53:58 | |
March, May. | 0:53:58 | 0:54:00 | |
So, they've got a matter of months to collect enough hay | 0:54:00 | 0:54:04 | |
to get them through the whole of the winter. | 0:54:04 | 0:54:07 | |
Yes. They're busy little bees, that's for sure. | 0:54:07 | 0:54:11 | |
Pikas love a cool climate. | 0:54:14 | 0:54:16 | |
Just a few hours' exposure | 0:54:16 | 0:54:18 | |
to temperatures of 21 degrees can prove fatal. | 0:54:18 | 0:54:22 | |
So they can only exist in Yellowstone above 2,000 metres. | 0:54:23 | 0:54:28 | |
Soon, even here, they may have nowhere left to go. | 0:54:30 | 0:54:35 | |
Because these animals are such high alpine specialists, | 0:54:36 | 0:54:40 | |
they can't survive at the lower elevations. | 0:54:40 | 0:54:43 | |
Does that make them particularly vulnerable | 0:54:43 | 0:54:45 | |
-to things like climatic changes? -Absolutely. | 0:54:45 | 0:54:48 | |
They are very sensitive to heat. | 0:54:48 | 0:54:50 | |
And so as climate change and the habitat changes for them, | 0:54:50 | 0:54:55 | |
they're going to move upslope. | 0:54:55 | 0:54:57 | |
You're already upslope at this point, you can't go any further. | 0:54:59 | 0:55:02 | |
And so, for the pika, you know, they don't have anywhere to move. | 0:55:02 | 0:55:06 | |
They're running into the sky. | 0:55:06 | 0:55:07 | |
Scientists have already seen pikas disappear | 0:55:13 | 0:55:16 | |
from one-third of their former strongholds | 0:55:16 | 0:55:19 | |
in warmer states to the south. | 0:55:19 | 0:55:21 | |
But Yellowstone's high country still provides sanctuary. | 0:55:22 | 0:55:26 | |
At least for now. | 0:55:26 | 0:55:29 | |
I have hope. I don't think we should lose hope. | 0:55:31 | 0:55:34 | |
Because they're too cute to go extinct! | 0:55:34 | 0:55:37 | |
That's one very good reason | 0:55:38 | 0:55:41 | |
we should all be there to save the pika | 0:55:41 | 0:55:43 | |
is they're just too cute to go extinct! | 0:55:43 | 0:55:46 | |
PIKA CALLS | 0:55:47 | 0:55:49 | |
The arrival of autumn marks the end of the great thaw. | 0:55:55 | 0:55:59 | |
We've seen how the dramatic seasonal changes | 0:56:01 | 0:56:04 | |
affected Yellowstone's wildlife. | 0:56:04 | 0:56:07 | |
The mild winter meant the wolves struggled | 0:56:07 | 0:56:10 | |
to hunt strong, well-fed prey. | 0:56:10 | 0:56:13 | |
And many went hungry. | 0:56:15 | 0:56:16 | |
WOLF HOWLS | 0:56:16 | 0:56:19 | |
But in the summer, they used their cunning | 0:56:19 | 0:56:23 | |
to find food and keep their pups alive. | 0:56:23 | 0:56:26 | |
The beavers survived the spring run-off | 0:56:29 | 0:56:33 | |
and were able to build an entirely new home to raise their three kits. | 0:56:33 | 0:56:38 | |
Our great grey owl runt beat all the odds | 0:56:42 | 0:56:45 | |
and fledged with its two siblings... | 0:56:45 | 0:56:47 | |
..giving this vulnerable population a much-needed boost. | 0:56:50 | 0:56:54 | |
The grizzly bears' race to fatten up started early | 0:56:56 | 0:56:59 | |
with the mild winter conditions. | 0:56:59 | 0:57:02 | |
The wet spring and early green-up revealed a bounty of food. | 0:57:02 | 0:57:07 | |
But by summer, they had to use all their resourcefulness to survive. | 0:57:07 | 0:57:12 | |
This has been a magical window into the lives of wildlife | 0:57:14 | 0:57:18 | |
in a truly spectacular landscape. | 0:57:18 | 0:57:21 | |
We've also seen a bigger picture unfold, | 0:57:23 | 0:57:26 | |
as scientists try to predict | 0:57:26 | 0:57:29 | |
what the future for Yellowstone will look like as the climate shifts. | 0:57:29 | 0:57:33 | |
I think what we do know is all of it's going to change | 0:57:35 | 0:57:38 | |
and it's changing pretty rapidly | 0:57:38 | 0:57:40 | |
and we don't really know how it's going to change. | 0:57:40 | 0:57:43 | |
There will be some good and some bad, | 0:57:43 | 0:57:44 | |
depending on what species you are, as climate change continues. | 0:57:44 | 0:57:47 | |
There are still many challenges ahead. | 0:57:49 | 0:57:53 | |
But if there's one thing that all of Yellowstone's animals share, | 0:57:54 | 0:57:58 | |
it's their incredible ability to adapt to extreme change. | 0:57:58 | 0:58:03 | |
And this will give them the best possible chance to survive, | 0:58:05 | 0:58:09 | |
whatever the future brings. | 0:58:09 | 0:58:11 |