Chapter 5

The cold, rainy afternoon became a cold, rainy evening and still the bear watched them. 

After his nap, Dyer walked a few steps through the drizzle to the tent next to his, where Chase and Castañeda-Mendez were relaxing. He had just read a poem that felt so right he had to share it with someone. Through the nylon walls of the tent, he read to them Whitman’s “Me Imperturbe.”

Me, wherever my life is lived, O to be self-balanced for contingencies! 

O to confront night, storms, hunger, ridicule, accidents, rebuffs, as the trees and animals do.

At about 5 p.m. the campers made their way across a rocky strip to the cooking area. 

Up on the ledge, the bear appeared to be lounging. Using the zoom lenses on their cameras, they watched it roll on its back and then lie on its belly, resting its head on its crossed forelegs. To Frankel, it looked like a big dog. To others, including Dyer, it looked like a menace.

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The hikers couldn’t help but compare the polar bear that was watching them with the grizzly bears they were familiar with. Both species seemed curious about humans but not drawn to them. Both responded to loud noises or flares.

These reasonable conclusions, however, didn’t take into account what makes a polar bear a polar bear. Although polar bears and grizzlies share the vast majority of their DNA, it’s the differences between them, the subtle and not-so-subtle ways in which they’ve diverged, that define the polar bear.

Biologist Andrew Derocher began studying polar bears in 1984, when his work on grizzly bears led him to their Arctic descendants. In his 2012 book “Polar Bears: A Complete Guide to their Biology and Behavior,” he imagines a scenario in which, sometime within the last 6 million years, grizzlies wandered onto shore-fast sea ice, either because they had extended their habitat into areas with cooler climates or because a cooling period had occurred. On the ice, they would have come face to face with seals, which at that point had no known predators and no reason to fear them. It would have been open season on this fat-filled, ample prey, but only for bears that were predisposed to adapt to the ice.

Gradually, grizzly bears evolved into polar bears.

“Presumably,” writes Derocher, “lighter colored bears fared better at catching seals until whiter bears became the norm.”

Polar bears’ hair isn’t actually white, it’s translucent, which allows it to radiate reflected light. The hairs are hollow—a trait polar bears share with deer—which helps insulate them and adds buoyancy when they’re in water. Beneath that hair, the bears’ skin evolved from pink to black, although scientists don’t know exactly why.

The bears’ hind feet sprouted an abundance of fur to provide traction and warmth. Their paws became webbed and their leg bones became denser than grizzlies’, allowing them to swim long distances and helping them earn their scientific name, Ursus maritimus.

The bears’ skulls changed, too. They became longer and narrower, allowing the air the bears inhaled to be better warmed and helping them capture prey in tight spots, like birth lairs and breathing holes. Their eyes became slightly elevated, a possible adaptation for the aquatic lifestyle.

The Arctic climate made it harder for females to carry large litters to term, so the litter size shrank, from three to four for grizzlies to an average of two for polar bears. As the litter size shrank, so did the number of teats for nursing. Grizzlies and American black bears have six; polar bears have four. 

Polar bears grew larger, too. Although some sub-populations of grizzlies are as big as large polar bears, polar bears are generally larger than grizzlies or any other bears—and are among the world’s largest mammals.

These physical changes happened in tandem with changes in the bears’ habits, Derocher writes in his book.

Since life on sea ice didn’t expose the bears to the flora that grizzly bears feed on, polar bears became carnivores, with a hunting style tailored for routing sea creatures from beneath the ice. Their skulls—now too narrow to allow them to effectively chew coarse vegetation—were ideal for this work.

Hunting was best in cold weather, which gave them access to their prey through the thick layer of sea ice. The bears stopped hibernating in the winter, except for expectant mothers.

These changes happened over millennia—but just how many millennia remains an open question. The oldest polar bear fossil, a jawbone, is between 110,000 and 130,000 years old. Analysis of the jawbone showed that this ancient bear’s diet was similar to that of modern polar bears. Its primary prey was seals and small whales, rather than the mix of fresh water fish, land mammals and plants that brown bears eat.

While we don’t know exactly how long it took for natural selection to skate its way across the sea ice and form a species uniquely prepared to thrive there, the science is clear on what’s happening now. The sea ice has up and changed on the bears, in the course of just a few decades. The question now, of course, is how will the bears respond?

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Half of the Sierra Club hikers helped prep and cook dinner that night: cream of potato soup, pesto pasta, cheesecake with blueberries and almonds. The others handled cleanup.

Remote locations and small groups make for fast friendships, and they were already comfortable enough with each other to mimic the soft drawl of Dyer’s Maine accent and share stories of past trips and their lives back home. 

They didn’t talk much about the bear that was still watching them from the ledge. It seemed almost like a piece of the landscape—just one more detail in their majestic setting.

Castañeda-Mendez felt reassured by the bear interactions they’d had that day. The mother and cub hadn’t seemed the least bit interested in them. And the bear up the ledge had responded to the flare in the way they had hoped it would.

But Dyer couldn’t shake his sense of uneasiness.

“Why don’t we post a watch?” he asked Gross after dinner. They could take two-hour shifts overnight until the bear was gone, he suggested.

But Gross wasn’t worried. “That’s what the fence is for,” he told Dyer. They had checked the fence, to make sure the wires were taut and the battery was switched on. Gross and Chase had done their homework; they were sure the fence would keep them safe.

Dyer thought back to their orientation at Barnoin River Camp where he remembered Lagacé telling them, “Polar bear touches that, you won’t have to worry.”

The group tucked into their sleeping bags. Just the thin nylon of their tents separated them from the vastness around them and the polar bear watching from 300 yards away. 

They had faith in their fence.

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Rodman woke in the middle of the night to the sound of screaming. For a moment he was frightened. Then he realized it was Chase, in the tent next door, having a nightmare. He could hear Castañeda-Mendez soothing her.

Isenberg slept fitfully, too. Each time he woke up, he checked to see if the bear was still there.

“Sure enough he was, sure enough he was…” And then, about 1 a.m., “He wasn’t.” It was unnerving, not knowing where the bear was, but there was nothing Isenberg could do about it. He went back to sleep.

The next morning was cold and rainy. The hikers bundled into layers—jackets, waterproof pants, winter hats and gloves—and hung around the campsite for a couple of hours, hoping the sky would clear so they could move on to their next location. When it became evident the weather wasn’t going to cooperate, they packed up their daypacks and went exploring again. 

This time they hiked northwest, in the direction they would be heading the next day. From one high point, they looked down on the valley where they planned to camp.

Again, they were surrounded by wildlife: whales in the fjord, caribou, ptarmigan, black bear scat full of berries. By afternoon the weather began improving and they peeled off some of their warm layers. They stopped at a rock perched high above their campsite to take silly pictures of each other.

When they got back to camp, Chase unpacked a little happy hour for them to enjoy: salami, crackers and Bacardi 151 rum mixed with lemonade. “It was a celebration,” she said. A celebration of being in a beautiful place, far from civilization, with people whose company they enjoyed.

As they cooked dinner that night, they talked excitedly about moving on the next day. Before Gross turned in, he made sure everyone was set for the night and walked the camp’s perimeter, confirming that the electric fence was still working.

Isenberg detached the fly from his tent so he could watch the clearing sky. It was too early in the year for the Northern Lights to appear, but he wanted to be ready, just in case.

Dyer pulled on his silk long underwear and slid into his sleeping bag. He’d always been able to fall asleep anywhere, and this night was no exception.

Before Gross crawled into his sleeping bag, he tucked his flare gun into his boot, as he did every night. He fell asleep listening to the waves against the gravelly beach of Nachvak Fjord.

Next: Chapter 6

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