Grizzly 399 was believed to be 28 years old and one of the oldest known grizzly bears still reproducing before a car crash killed her.

Grizzly Bear 399 was killed on Tuesday in a car collision south of Jackson, Wyo., the National Park Service said. She was fatally hit by a vehicle on Highway 26/89 in Snake River Canyon and was later identified by her ear tags and microchip. The mama bear had a yearling cub with her at the time, but it’s still missing.

Grizzly 399, which delighted wildlife watchers for more than a decade, was killed Tuesday night in a collision with a vehicle