MISSOULA, Mont. (AP) — Pioneering grizzly bear expert and advocate Chuck Jonkel has died. Jamie Jonkel, a state bear manager, said Thursday his father died of natural causes Tuesday evening at nursing home.

He was 85. Jonkel led the Border Grizzly Project shortly after the bears were placed under federal protection in 1975. He founded the International Wildlife Film Festival in Missoula, which sought scientifically accurate films. He also was on the faculty at the University of Montana and researched polar bears in the Arctic Circle.

Fellow instructor Dan Pletscher said Jonkel even acted like a grizzly bear. He knew which plants were edible and scratched his back on a tree when talking to a class in the field. State bear biologist Mike Madel told the Missoulian that Jonkel inspired the careers of most of today's bear scientists.