- You can go days without food, traverse unimaginable distances, endure relentless blizzards. But if you're a wolf on
the edge of the Arctic, up against the biggest predator, there's one thing you can't do without... (dramatic music) The pack. (dramatic music) (wind blowing) At first glance, the Arctic
feels brutally devoid of life, though a select group of animals have figured out a way to thrive. (seal howling) But the real force here
works quietly underfoot. Every winter, sea ice
starts small and delicate. Then it grows over
millions of square miles. How is it possible that this freezer holds the key to our entire planet? Like a lung, sea ice breathes life into the Arctic every year, in a cycle that impacts the
climate across the globe. This is the story from the
edge of the Canadian Arctic where it all starts. (dramatic music) My name's Bertie Gregory, and I'm a National Geographic wildlife filmmaker. Everything is at stake. We're all waiting for The Big Freeze. (solemn music) This is gray wolf territory, but right now it's also a
polar bear migration path, and until the sea freezes over, these two mighty predators will have to share this coastline. We've received a tip-off about
a very cool pack of wolves, and reportedly they've
been seen harassing, or even hunting polar bears. This has never been filmed before, so we're buzzing there
now to see if we can try and catch up with them. Wolves here are always on the move. They live in such a harsh environment that they roam up to 1000
square miles in search of prey. Hey, look. We don't want to spook him. He's coming right up to us right now. That's a pretty bold wolf. (laughs) I've spent months
looking for wolves before and never seen one. - Yeah, so much to going to
look for them. (laughing) - Wolf. Over the snow drift, just on the right. He's going for the bear. (dramatic music) Polar bears are the apex
predators of the Arctic. Weighing up to 1500 pounds, no one dares touch them, except the wolves we're tracking. If they can catch this bear, it would feed the pack for a week. But this bear is not having it. (growling) There's another one. - [Man] There's three,
there's a third one coming. - A big pack of wolves
could take down a polar bear but with only three against one, who is predator and who is prey? (dramatic music) The bear runs the numbers, and goes for it. (growling) (dramatic music) That is not a chase you see every day. Imagine chasing after a polar bear, a massive, really dangerous predator. When is that ever a good thing that you should try and eat? Finding these wolves is
gonna be a real challenge. You know, even though it
was here this morning, this afternoon it could
be 20 miles that way, it could be 20 miles that way. And I guess we just gotta
get really, really lucky. (motor revving) We're pretty stuck. Got ourselves a pretty good one. Yeah. We haven't found any wolves, but we have found some
of their favorite food. There's at least one moose. Isn't it amazing? Don't spook, don't spook, don't spook. He's got a massive rack. Oh, he's coming over, backing up. It's like a giant horse on steroids. (laughter) (dramatic music) It's our ninth day searching. Still no wolf pack. They just keep eluding us. (dramatic music) - [Man] I'm gonna go up
the tree and have a look. (dramatic music) - Well, we found the
wolves, and they're asleep, so we're trying to sneak
in so they don't wake up. This has gotta be the most
unstealthy approach ever. We've actually got really lucky. We're downwind of them,
and their sense of smell is about 100 times better than us, so if we were upwind they'd know what we had for breakfast, they'd know the last time we showered, which wasn't very recently. They'd know everything about us. (howling) (howling) You can hear, they all
howl at different pitches. They're almost like a wild edition of an a cappella group. And even if you get a new wolf in, the new wolf to the pack will
adjust the pitch in its howl to the rest of the pack to make sure it's not copying one of them. (howling) There's a big male,
must be the alpha male. He seems to be calling the shots, and he's got this big chunk
out the side of his face. He's running with a bit of a limp. You know, one of the
reasons they live in packs is 'cause if they get injured, the rest of the pack can
still provide for them. Wolf packs are also led
by the alpha female. Together they decide
where and when to hunt. This pair are also the only ones to breed, adding new pups to the pack each year. They're coming over. In the movies and in the media, we like to demonize these animals. But despite being just a few feet away, I never felt any threat in those eyes, just curiosity. They hung out with us
like this for over an hour until the alpha female called the pack and off they went. (howling) Time to hunt. There used to be two million
wolves in North America, but 400 years of systematic extermination has left us with just 80,000. Wild places depend on these wolves, as they regulate prey populations. We must give them the
chance to bounce back. Each hunt follows a strategy. First they close in. (dramatic music) Ready? (dramatic music) Charge. (dramatic music) The alphas must make a quick decision. Can they take down a
bull moose in his prime? Is this worth exhausting
the entire family? (dramatic music) Not this time. Better find a new target. (howling) (slow tempo music)
