JACKSON, Wyo. — A grizzly bear that officials believe is the oldest female reproductive bear in the Greater Yellowstone ecosystem was killed Tuesday when it was struck by a car on a highway near Jackson.

The National Park Service says in a news release that the identity of the bear, known as Grizzly Bear 399, was confirmed through ear tags and a microchip. The bear had a one-year-old cub with her when she was struck on Highway 26-89 in the Snake River Canyon. Officials do not believe the cub was injured, but have not found it.

“Unfortunately, vehicle collisions with wildlife, including grizzly bears, are not uncommon throughout their range,” the release said. The driver of the vehicle was not injured and the cause of the accident remains under investigation.

No. 399 was 28 years old and well-known among nature lovers and park officials. Every spring, observers eagerly waited to see her emerge from her den to see how many young she had given birth over the winter – and then quickly shared the news online.

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

“The grizzly bear is an iconic species that helps make the Greater Yellowstone ecosystem exceptional. Grizzly bear 399 was perhaps the most prominent ambassador of this species,” Chip Jenkins, superintendent of Grand Teton National Park, said in a statement. “She inspired countless visitors to support conservation around the world and we will miss her.”

The mama bear has fans around the world, said tour guides Jack and Gina Bayles, who run Team 399's Facebook page and planned to visit the site where she was killed.

“You could say she was the accidental ambassador of the species,” Jack Bayles said. “My biggest concern is that people are now losing interest in bears.”

According to the National Parks Service, vehicle collisions have resulted in the deaths of 49 grizzly bears in the Greater Yellowstone Ecosystem between 2009 and 2023. In 2024, two grizzly bears died in collisions.

(The Associated Press contributed to this story.)