This is part of our Road Trip 2018 summer series "Taking It to Extremes," which looks at what happens when people mix everyday tech with insane situations.

Heavy gray clouds hang low in Alaska's Denali National Park and Preserve this September morning. There's an 80 percent chance of rain, but we've lucked out with only a light mist so far. I'm walking along the banks of the Teklanika River, which cuts a 90-mile swath through inland Alaska, with Bridget Borg, a wildlife biologist with the National Park Service, and biological assistant Kaija Klauder.

It's 45 degrees Fahrenheit (7 Celsius). Klauder is wearing chest-high waterproof pants, a flannel shirt and sturdy trail boots. Borg has on waterproof pants, a shirt, a sweater and a down vest. I feel woefully underprepared in my leggings, wool socks and basic hiking boots. Borg periodically calls out, "Hey, bear," to avoid surprising any nearby grizzly or black bears. There's no trail. We're bushwhacking, carefully cutting through thick bushes already bursting with fall colors as well as soapberry shrubs. Bears love them, they tell me.

We're heading to a wolf den about a mile up river. There shouldn't be any wolves there right now, though, based on the data from GPS collars Borg and Klauder use to track nine wolf packs living in the park. The GPS logs the wolves' location every four hours to conserve the collar batteries, Klauder says.

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Klauder identifies animal tracks as we walk — lynx, caribou, bear, snowshoe hare, wolf — as well as other signs of wildlife in the area. "Why is it white?" I ask, staring down at a large pile of wolf poop. It's probably from eating bones, Borg says casually.

Borg and Klauder monitor Denali's wolves for the NPS, part of the service's 32-year-long wolf research project. That's no small feat in an area bigger than New Hampshire.

The NPS spends roughly $125,000 a year monitoring wolves in Denali. The software and equipment used to track the wolves "is the biggest chunk of our funding on that particular project," says Patricia Owen, a wildlife biologist with the Denali National Park and Preserve.

Why spend six figures a year to monitor wolves?

It's because wolves are a keystone species. Take away the wolf, and the entire Denali ecosystem could change — which is just what happened in the 1920s, when federal and local governments eradicated the gray wolf in the Greater Yellowstone Ecosystem. Elk populations exploded. Overgrazing dramatically reduced the number of seeds, wetland plants and other food sources that fish, birds and other species depended on. And because elk had gobbled up the seeds and saplings that would have grown into trees, lake and river temperatures rose from lack of shade.

Now playing: Watch this: Tracking the hidden lives of Denali's wolves

In contrast, Denali has remained largely untouched by humans. For biologists, the 6-million-acre park (including 2.2 million acres of federally designated wilderness) serves as a kind of living laboratory. Monitoring how animals interact shows scientists how the pieces of its ecological puzzle work and fit together.

"Wolves matter because they represent a true wild," Doug Smith, Yellowstone National Park senior wildlife biologist, tells me. "Real nature has to have all the parts."

We're going where?

Borg and Klauder made this same trek the previous September to set up motion-detecting, heat-sensing cameras in the hope of capturing images of a wolf pack in and around its den. Now I'm following them back to retrieve the SD cards inside the tree-mounted cameras — and to look at a year's worth of footage for the first time.

Before leaving the park headquarters that morning, Klauder had pulled up computer maps showing each collared wolf's GPS location within the past four hours.

The maps show dots — color-coded by pack — representing dozens of wolves in clusters on the screen. According to the most recent count, the smallest pack contains only two wolves; the largest has 17. The average pack has six or seven.

The collar feels heavy to me, but it only weighs about 2 pounds. There have been three iterations, and this new version has been designed to better withstand extreme weather, submersion in lakes and rivers, and animal bites. Each collar is outfitted with a GPS logger and a radio transmitter.

Take away the wolf, and the entire Denali ecosystem could change.

The GPS tells biologists the wolves' location coordinates and the radio transmitter lets them know if wolves are close.

How do they get those collars on the wolves, I hear you ask. The first step is tranquilizing up to three wolves in each pack using darts shot from helicopters. The teams then choose the healthiest wolves to collar, often the pack leaders.

When we're ready to set out, Borg grabs a dark gray, H-shaped device, about 18 inches wide, and holds it up high. It's a telemetry antenna and it's looking for radio transmitters. The antenna typically picks up signals about 3 to 4 miles away, but that can vary by topography and weather.

A red sign next to our parked car reads:

AREA CLOSED: Critical Wildlife Habitat. Wildlife are denning or nesting in this area. Human presence may cause animals to abandon their young or become habituated. To minimize disturbance this area is closed to all entry.

These signs are visible along many sections of Denali's park road.

We start walking.

A home with a view

After about a mile of crunching over rocks and sand, wading through shallow water and scraping past thick shrubs, Borg and Klauder abruptly turn and face a steep tree-covered ridge.

When Borg and I spoke over the phone about visiting a wolf den, she had described "a bit of a scramble" at the end. This was it.

Females give birth in dens and stay there with the pups for about eight weeks before the entire pack moves to a "rendezvous site." The rest of the pack uses the site as a central meeting point in between hunting and bringing back food. At three months old, the pups start to go on short hunts with the pack.

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The pack abandons the rendezvous site when the pups are around six months old.

Dens vary, but Denali wolves typically dig up holes in sandy soil along rivers or on hillsides under trees. This pack chose the latter.

I'm reaching for tree branches to hoist myself up the steep incline leading to the den. It seems like a terribly inconvenient spot to build a home.

But at the top of the hill, the wall of vegetation gives way to a flat grassy opening surrounded by trees on all sides. It isn't just cozy — it's downright picturesque. And for an agile wolf, the jaunt from the river to the top of the ridge isn't the same physical feat it was for me with an unwieldy bag full of camera gear, water and snacks.

There are two large battery-powered cameras attached to trees on the bluff, facing potential denning sites in different directions. The cameras are camouflaged and blend in well with the surroundings. Since winter temperatures can drop to minus 40 degrees Fahrenheit, the cameras have to be tough enough to handle pretty much anything.

Each camera is attached to a tree by a thick cable. One of the cameras has noticeable bite marks on it — possibly a chew toy for the wolf pups. Borg and Klauder unhook the cables, remove the weatherproof casings, open the cameras and retrieve the SD cards.

These cameras aren't connected to a cellular tower or a Wi-Fi network — they don't transmit images as they're taken. Borg and Klauder had to wait an entire year to see if the wolf pack from last year chose to den here again. They did.

Until next year

The two women talk excitedly as they sit on the ground next to the wolf den, scrolling through the images. They note physical characteristics of the wolves, as well as details about other wildlife.

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There's a wolverine, a moose, a bear and tons of lynxes. The lynxes are a surprise. They haven't seen this many up here before. There are also lots of shots of snowshoe hares. The hares are annoying because the dozen or more images of them likely caused one of the camera's batteries to drain more quickly than expected.

But the cameras got a lot of wolf images, too. There are shots of adult wolves walking solemnly through the den site and of pups playing.

Borg and Klauder grab identical new cameras and set them up like they were before. They're hoping the pack will return again in the spring. Then, the following September, the two biologists will make the exact same climb up here and scroll through another year's worth of footage to add to Denali's decades-long wolf research effort.

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