CHEYENNE, Wyo. (AP) -- A famous grizzly bear beloved for decades by countless tourists, biologists and professional wildlife photographers in Grand Teton National Park is dead after being struck by a vehicle in western Wyoming.

Grizzly No. 399 died Tuesday night on a highway in Snake River Canyon south of Jackson, park officials said in a statement Wednesday, adding the driver was unhurt. A yearling cub was with the grizzly when she was struck and though not believed to have been hurt, its whereabouts were unknown, according to the statement.

The circumstances of the crash were unclear. Grand Teton and U.S. Fish and Wildlife Service officials said they had no further information to release about it.

At 28 years old, No. 399 was the oldest known reproducing female grizzly in the Yellowstone ecosystem. Each spring, wildlife enthusiasts eagerly awaited her emergence from her den to see how many cubs she had birthed over the winter -- then quickly shared the news online.

Named for the identity tag affixed by researchers to her ear, the grizzly amazed watchers by continuing to reproduce into old age. Unlike many grizzly bears, she was often seen near roads in Grand Teton, drawing crowds and traffic jams.

Scientists speculate such behavior kept male grizzlies at a distance so they would not be a threat to her cubs. Some believe male grizzlies kill cubs to bring the mother into heat.

The bear had 18 known cubs in eight litters over the years, including a litter of four in 2020. She stood around 7 feet (2.1 meters) tall and weighed about 400 pounds (180 kilograms).

Hundreds of visitors at times would gather at a wide meadow to see her in the evenings, recalled Grand Teton bear biologist Justin Schwabedissen.

Some youngsters "just thought that was just the coolest thing in the world to see a bear out there, cubs wrestling in the wildflowers," Schwabedissen said.

Another time he met a just-retired Midwest factory worker whose dream was to see a bear in the wild.

"She was in tears that night from being able to have an opportunity to see her," Schwabedissen said.

News of the bear's death spread quickly on a Facebook page that tracks the grizzly and other wildlife in Grand Teton and Yellowstone national parks. By late Wednesday more than 2,000 people posted comments calling the bear a "magnificent queen," an "icon" and an "incredible ambassador for her species."

They were heartbroken and devastated by her death, calling it a tragic loss.

The momma bear had fans all over the world, said tour guides Jack and Gina Bayles, who run the Team 399 Facebook page and planned to visit the site where she was killed.

"You might say she was the accidental ambassador of the species," Jack Bayles said. "My single biggest concern is that people are now gonna lose interest in bears."

The grizzly lived through a time of strife over her species in the region, as state officials have sought to gain management control over grizzlies from the U.S. Fish and Wildlife Service, saying the bears' numbers have rebounded past the point of being at risk.

Conservation groups have objected, saying climate change imperils some of the bears' key food sources including whitebark pine cones.

Some 50,000 grizzlies once roamed the western United States. But outside Alaska they are now confined to pockets in the Yellowstone region and northern Rockies. They dwindled in the Yellowstone region to just over 100 animals by 1975, when they were first protected as a threatened species.

The region encompassing Grand Teton and Yellowstone national parks and surrounding areas in Wyoming, Montana and Idaho is now home to some 1,000 grizzlies. They remain federally protected but in an ongoing tug-of-war between political and court decisions have bounced off and back on the threatened list twice in recent years.

Government biologists say the population is healthy and officials from the three Yellowstone states continue to seek their removal from federal protection.

On average, about three grizzlies annually in the region are killed in vehicle collisions, with 51 killed since 2009, according to data collected by researchers and released by the park. No. 399 was the second grizzly killed in the region by a vehicle this year.

"Wildlife vehicle collisions and conflict are unfortunate. We are thankful the driver is okay and understand the community is saddened to hear that grizzly bear 399 has died," Wyoming Game and Fish Department Director Angi Bruce said in the statement.