Timothy Treadwell was a quixotic, towheaded dude of a man determined to defy the boundary between man and bear. Actually, he didn't appear to perceive much of a boundary at all. As far as he was concerned, he was one of them.
One bear didn't quite see it that way. In the fall of 2003, Treadwell, an actor-turned-animal preservationist, and his girlfriend were eaten by one of the Alaskan beasts he spent a decade trying to protect.
His passion for wildlife elevated his plight from kooky folly to a nearly religious act, most of which he recorded with a video camera. If this story of a man's ultimately unwinnable struggle with the environment sounds like a Werner Herzog movie, now it is. ''Grizzly Man," a sublime new documentary, assembles Treadwell's video diaries and interviews with his parents and closest friends to relate a haunting cautionary tale.
According to Herzog, who doesn't narrate the movie so much as furnish unstinting running commentary on Treadwell's footage and psyche, Treadwell's wish to ''leave the confines of his humanness to bond with the bears" was a transgression. ''In doing so," Herzog explains in his insinuating German brogue, ''he crossed an invisible borderline."
We could say the same of Herzog, who for five decades has been the dark lord of transgressive filmmaking. He's given us a film starring all little people (1970's ''Even Dwarves Started Small"), one about a fanatic who dragged conquistadors through the Peruvian jungle (1972's ''Aguirre, Wrath of God") and another about a fanatic who built an opera house in the same tropical climes (1982's ''Fitzcarraldo"). Those difficult, endlessly fascinating movies (and a handful more), with their legendary back stories and extreme stunts, were Herzog in his domineering, some would say cruelly combative, prime. Back then he battled the elements, the earth, and the actors, with leading man Klaus Kinski as his greatest opponent.
But in his late 50s and 60s (he'll be 63 next month), Herzog hit a new stride with a fresh round of nonfiction. I wouldn't characterize this current phase as mellow, but even when they flirt with exploitation, his recent documentaries have allowed Herzog to humanize himself. (This a man who, in the name of cinema, once climbed an erupting volcano and, on a separate occasion, hypnotized his cast.) ''Grizzly Man" is the fourth of his tremendous documentary psychodramas, following 1997's ''Little Dieter Needs to Fly" and 1999's ''Wings of Hope" and ''My Best Friend." Despite the ghastly circumstances, it's the most compassionate movie he's ever made.
Treadwell's ideas are perfectly suited to Herzog's cinematic taste and philosophical beliefs. But the subject's life arouses the journalist in the filmmaker. The gruesome particulars of the deadly mauling are delivered in a surreal comic fashion by coroner Franc G. Fallico who speaks directly into the camera about how Treadwell and his companion, Amie Huguenard, perished. Oddly, Fallico seems like a figure from an Errol Morris film, and Herzog shrewdly uses him to handle the forensic angle, while the director argues for Treadwell as a psychologically troubled young man.
The man we find in the footage is impish and childlike. In his simultaneous delusion and naivete, Treadwell variously recalls Michael Jackson, Pee-wee Herman, and Johnny Depp's Willy Wonka.
Yet Herzog complicates the picture with the late discovery that Treadwell might have suffered from megalomania. Indeed, we see Treadwell launch into an expletive-laced screed that practically gives Herzog a Kinski flashback. Still, the director expresses sincere admiration for his subject's purity and impregnable spirit. The preservationist in Treadwell understands that the bears are dangerous, but the empathizer in him doesn't see how the danger is personally relevant.
Nonetheless, by telling us up front what they're capable of, Herzog trains us to fear the animals. And the flying bugs that swarm the camera on several occasions signal a note of inevitable doom: We know there is carrion out there.
Yet Herzog, in a merciful show of decorum, does not subject us to it. The deaths were recorded only on an audio track, and in the movie's most powerful moment, Herzog actually insists that a devastated ex-girlfriend of Treadwell's never listen to the tape. He wants her to burn it.
Throughout ''Grizzly Man," Herzog cuts firmly but delicately past Treadwell's ecological romance, seeing passive-aggressive fatalism where some might see a martyr. He also reminds us that he's learned a lot during his formidable career. Nature has laws, and, however great a temptation it might be to break them, they should be heeded.
Wesley Morris can be reached at firstname.lastname@example.org.