[1] On October 5, 2003, Treadwell and his girlfriend Amie Huguenard were killed and almost fully eaten by a 28-year-old male bear whose stomach was later found to contain human remains and clothing.

[2] Treadwell's life, work, and death were the subject of Werner Herzog's critically acclaimed documentary film Grizzly Man (2005).

[3][4] Treadwell was born in Mineola, Long Island, New York, one of five children of Val Dexter and Carol Ann (née Bartell).

[8] Treadwell spent the early part of each season camping on the 'Big Green', an open area of bear grass in Hallo Bay on the Katmai Coast.

[1] In contrast, Tom Smith, a research ecologist with the Alaska Science Center of the U.S. Geological Survey, declared that Treadwell "...was breaking every park rule that there was, in terms of distance to the bears, harassing wildlife, and interfering with natural processes.

Treadwell recorded almost 100 hours of video footage (some of which was later used to create the documentary Grizzly Man) and produced a large collection of still photographs.

He traveled throughout the United States to educate school children about bears and appeared on the Discovery Channel, the Late Show with David Letterman, and Dateline NBC to discuss his experiences.

Treadwell and Palovak founded Grizzly People, an organization devoted to protecting bears and preserving their wilderness habitat.

[11] Naturalist Charlie Russell, who studied bears, raised them, and lived with them in Kamchatka, Russia, for a decade, worked with Treadwell.

Russell was critical of Grizzly Man, saying it was unfair to Treadwell, and if Palovak "really was a protector of bears, she should have looked for a filmmaker who would have been sympathetic towards them.

According to court records as reported by the Anchorage Daily News, though, the guilty parties were charged with poaching wildlife along Funnel Creek in the preserve, an area open to hunting that borders the national park.

In Grizzly Man, Werner Herzog states that according to Treadwell's diaries, Huguenard feared bears and felt very uncomfortable in their presence.

Some of the last footage taken by Treadwell, hours before his death, includes video of a bear diving into the river repeatedly for a piece of dead salmon.

The next day, October 6, Willy Fulton, a Kodiak air taxi pilot, arrived at Treadwell and Huguenard's campsite to pick them up but found the area abandoned, except for a bear, and contacted the local park rangers.

[16] A video camera recovered at the site proved to have been operating during the attack, but police said that the six-minute tape contained only voices and cries as a brown bear mauled Treadwell to death.

[17] The fact that the tape contained only sound led troopers to believe the attack might have happened while the camera was stuffed in a duffel bag or during the dark of night.

In Grizzly Man,[4] filmmaker Herzog claims that the lens cap of the camera was left on, suggesting that Treadwell and Huguenard were in the process of setting up for another video sequence when the attack happened.