Not long after Chris Palmer broke into environmental filmmaking in the early 1980s, he brought home a newly completed film to show his wife, Gail.

She loved it -- especially the close-up of the grizzly bear splashing in a stream. She asked Palmer how the crew had captured the sound of water dripping from the bear's paws. He confessed: The sound guy had miked up a water basin and recorded splashing sounds made by his own hands.

She turned to him and said, "You're a big fake."

Three decades later, Palmer hasn't quite recovered. And, at 63, he has written a confessional for an entire industry. "Shooting in the Wild," published this year by Sierra Club Books, exposes the unpleasant secrets of environmental filmmaking: manufactured sounds, staged fights, wild animals that aren't quite wild filmed in nature that isn't entirely natural.

Nature documentaries "carry the promise of authenticity," Palmer said, speaking on a morning stroll through the manufactured wilderness of the National Zoo. Nature filmmakers profess to present animal life as it is lived, untouched by mankind. Yet human fingerprints are everywhere.

Palmer's book underscores the fundamental challenge of wildlife filmmaking: Nature is frequently boring. Wild animals prefer not to be seen.

"If you sit in the wild and watch wildlife, nothing happens for a very long time," said Maggie Burnette Stogner, an environmental filmmaker who works with Palmer on the American University faculty. "That's mostly what happens in wildlife."

Nature footage is hard-earned. A crew might spend six weeks in discomfort and tedium for a few moments of dramatic cinema. Certain shots -- animal births, or predators seizing prey -- are difficult to capture by chance. So some filmmakers set them up.

The lemmings that plunge to their deaths in the 1958 Disney documentary "White Wilderness" were hurled ingloriously to their doom by members of the crew, as a Canadian documentary revealed. Palmer writes that Marlin Perkins, host of television's "Wild Kingdom," was known to bait animals into combat and to film captive beasts deposited into the wild, and that the avian stars of the 2001 film "Winged Migration" were trained to fly around cameras.

Palmer asserts that manipulation pervades his field. Game farms, he writes, have built a cottage industry around supplying nature programs with exotic animals. Much of the sound in wildlife films is manufactured in the studio. Interactions between predator and prey are routinely staged.

"And if you see a bear feeding on a deer carcass in a film," Palmer writes, "it is almost certainly a tame bear searching for hidden jellybeans in the entrails of the deer's stomach."

Even David Attenborough, the dean of British environmental filmmaking, admitted arranging for scorpions to mate in a studio, "with a painted sunset and Styrofoam clouds" as a backdrop, Palmer writes.