An American environmentalist and documentary filmmaker, he was best known for his work with grizzly bears in Alaska's Katmai National Park. Passionate about wildlife, his dedication to the bears led to the creation of the Grizzly People organization, aimed at preserving bear habitats. His life and work were chronicled in Werner Herzog's documentary "Grizzly Man." Tragically, his life ended in 2003 during an encounter with a bear, highlighting the complex relationship between humans and wildlife.