For a long, anxious stretch this spring, Bernie Scates staged a stake-out in a rural corner of Jackson Hole, hoping rampant speculation about Grizzly 399’s possible death was a Twainian exaggeration. Nowhere to be found, the legendary mother grizzly bear was running late in emerging from her den after five months of winter slumber.

Then, on Tuesday, May 10 at exactly 10:13 am—Scates remembers looking at his wristwatch—he became startled by what appeared to be a massive brown boulder moving down the flanks of Pilgrim Creek. It was this precise moment, Scates says, when he became the first to witness the most famous wild living bear in the world wandering out of the Bridger-Teton National Forest into Grand Teton National Park, shadowing a newborn, white-faced cub at her side.

Scates and millions of 399’s human followers around the globe—she’s been a sensation on social media—breathed a sigh of relief knowing that the 20-year-old ursid matriarch, responsible for producing an impressive 16 descendants, still survived. The good news traveled fast.

399 had not been poached, as a man claimed he had done in the local Jackson Hole newspaper a few months earlier, insisting he had killed the beloved roadside bear widely considered the cause celebre for grizzly conservation in the Greater Yellowstone Ecosystem.

399’s dramatic story figures into the current national debate over whether grizzlies in the region, safeguarded by the Endangered Species Act since 1975, should be removed from the federal list of protected animals. Discussions over the fate of America’s most iconic bear population, synonymous with Yellowstone National Park, is among the most contentious wildlife issues in recent history. (See Yellowstone's "bear bathtub.")

A Bear's Turbulent Life

399 first became a star when, in 2006, she appeared along the roadside in Grand Teton Park, supposition from biologists being that because a male bear had killed her first cub in the backcountry she wanted to find a safer place to raise subsequent broods.

A year later, 399 was nearly destroyed after she and her triplets mauled a hiker in Grand Teton who accidently stumbled upon an elk carcass they were feeding on. After the hiker pleaded to have 399 spared and park officials examined evidence, they ruled that the mother was only behaving naturally and shouldn’t be lethally removed.

View Images 399 and her cubs are often seen on or close to roads around Jackson Hole. Photograph by Bernie Scates

Over the last decade, 399, in fact, has shown no aggression toward people even as she and her offspring navigate huge crowds of people gathered along the highway in “bear jams.”

In recent years, 399 became arguably better known than Scarface, the male bruin in Yellowstone, and Cecil the lion, who made his home in Zimbabwe’s Hwange National Park. But in 2015, both Scarface and Cecil were killed by hunters when they wandered outside national parks.

399 has been a muse for legendary Jackson Hole nature photographer Thomas D. Mangelsen, who features her in the new book Grizzlies of Pilgrim Creek. He’s spent the equivalent of two full years assembling a large portfolio of images focused on 399 and her extended family.

Reached on a boat anchored off Ecuador’s Galapagos Islands Tuesday, where he is leading a photo excursion with Art Wolfe and Frans Lanting, Mangelsen was overjoyed by the latest news of the bear.

“Every year she’s still with us is a miracle," said Mangelsen. "This could be the last cub she ever has because she’s pretty old in bear years," he adds. "Most bears don’t reach that age.”

More than half of 399's cubs or descendants have already died, often from run-ins with people or other bears, Mangelsen adds.

"That shows just how precarious it can be to grow a bear population, even with remarkably fertile mothers like 399,” he says.

Debate Over Protections Heats Up

In April, Mangelsen testified on Capitol Hill before members of the House Natural Resources Committee, saying he opposed the federal government’s proposal to remove the Greater Yellowstone grizzly population from protection under the Endangered Species Act. At the same hearing, his close friend Jane Goodall delivered remarks voicing her opposition to recommencing sport hunting of grizzlies if their management is returned to Wyoming, Montana and Idaho.

The U.S. Fish and Wildlife Service, who calls grizzly recovery one of the greatest conservation successes, says the bear population is biologically recovered and should now be managed by the states.

Goodall is among a list of nearly 60 scientists who say stripping federal protections from Greater Yellowstone grizzlies is premature. She also signed a letter to President Obama, which included famed conservation biologists E.O. Wilson and George Schaller.

Raising the stakes, grizzlies like 399 are anchors in an annual nature-tourism economy worth $1 billion to the communities around Yellowstone and Grand Teton parks.

“When 399 appeared there were only a handful of people waiting along Pilgrim Creek but as word spread a large group quickly assembled," said Scates, a 78-year-old retiree originally from Massachusetts. "It became a madhouse.”

399 was given her identity by researchers with the Interagency Grizzly Bear Study Team. Although she isn’t currently wearing a tracking collar, Scates says he made positive identification of her by a pair of distinctive scars on her face, likely caused by scraps with other bears.

Some government wildlife officials have dismissed 399 as a “celebrity bear” who causes problems for managers because of the large crowds she attracts.

Dan Wenk, superintendent of Yellowstone, endured a severe public backlash last summer when he decided to have a popular grizzly mother in Yellowstone euthanized, after she fatally mauled and partially ate a park hiker. The bears’ orphaned cubs were sent to The Toledo Zoo in Ohio.

Watch: How much do you know about grizzly bears?

Wenk says he supports delisting grizzlies but believes transboundary bears like 399, who spends much of her year inside Grand Teton National Park, should not be subjected to hunting because of their beloved status among park visitors. Montana this week also announced that it was upping its quota for the number of transboundary Yellowstone wolves allowed to be killed in the state’s annual sport hunt.

Not long ago, wildlife photographer Daryl Hunter, who, like Mangelsen, is among a throng of 399 admirers with cameras, recalled a conversation he had with an outfitter who guides big game hunts in Wyoming. “I met a guy who wants grizzly 399's rug on his wall, stating that because she is famous, she makes a better trophy,” Hunter said.

“Government wildlife agencies are charged with managing species to achieve positive outcomes at the population level but there’s no doubt that most people relate to animals on an individual level,” Wenk said recently as he was taking that message to Interior Secretary Sally Jewell and National Park Service Director Jon Jarvis. “I believe individual bears like 399 can solidify the sense of connection citizens feel to public lands and public wildlife they own.”