In late 1982, a year that saw humans kill a disturbing number of the few grizzly bears surviving in the contiguous United States, the National Audubon Society decided that action was needed to stanch the tide of extinction. There were numerous laws on the books to protect grizzlies (including the Endangered Species Act, under whose auspices the grizzly is listed as a threatened creature), but with Ronald Reagan as president and James Watt as secretary of the interior, enforcement was next to nonexistent.

In a typical case, a 500-pound adult male grizzly was shot in the back while feeding on a moose carcass in the Gallatin National Forest near Cooke City, Mont. Federal penalties for the crime can run as high as $20,000 and a year in jail, but in this case the killer, who pleaded self-defense, was fined $50. In the Yellowstone Park area, which is one of the last grizzly strongholds left in the Lower 48, twice as many bears were killed by people over the previous dozen years (approximately 400) as may remain in the entire population today (approximately 200).

Seeking a way to simultaneously prod government authorities and make poachers hesitate to pull the trigger on a grizzly, the Audubon Society unveiled a major reward program for tips on people who killed bears. Ten thousand posters were put up in grizzly country announcing that Audubon would pay up to $15,000 for information leading to the arrest and conviction of grizzly killers. Information started coming in almost immediately, and by February 1983 the program had produced its first conviction and cash payout. Due in part to Audubon's efforts, only six grizzlies were reported killed in the Lower 48 during 1983, or fewer than half the number of 1982.

Among the several factors that combined to make Audubon's bold reward program a reality, one of the most important was an article on grizzlies by Thomas McNamee that appeared in the November 1982 issue of Audubon magazine. "Breath-holding in Grizzly Country" was a splendid piece that managed to make vivid both the great bear and the human threats to its continued survival in the United States outside Alaska. In "The Grizzly Bear," McNamee has expanded the original article into a book on Ursus arctos horribilis, an animal that commands our attention not only because it is one of the few creatures in the world that can kill a man more or less at will, but also because it resembles man more than most other creatures outside the primate family. "We are both, after all, big, intelligent, omnivorous mammals," writes McNamee, "both at the top of our food chains, both highly dependent on learning; and neither has anything to fear among his fellow mammals except his occasionally murderous conspecific brethren and the other."

"The Grizzly Bear" follows a particular female grizzly and her cubs through a year in their lives, from one winter's hibernation to the next. McNamee, a poet whose verse has been published in The New Yorker, does a wonderful job of evoking the enigmatic and infinitely variable grizzly -- throwing a tree stump on top of a cached moose carcass, gorging on cutthroat trout spawning in the Yellowstone River above Yellowstone Lake, hanging out at the old dump near Cooke Pass, Montana. His bears are very believable, yet repeatedly surprising in their habits and capabilities (it turns out, for instance, that hibernating bears are the only animals in the world known to synthesize the materials they need for life from their own wastes through a process known as protein catabolism).

Curiously, McNamee is less successful in handling the human controversies that swirl around the grizzly, including the Audubon reward program he helped inspire. In the descriptive and naturalistic portions of the book, McNamee comes off as a knowing and enjoyable guide, but when he deals with the economic and political aspects of the story (that is to say the real power of human society that is arrayed against the bears) he seems both less at ease and less able to sort through the obfuscating techno-talk of competing individual, corporate and government interests. In the face of massive non-enforcement of laws and other snarling aspects of the human problem, McNamee remains polite, dry, removed, as if touched by some deep personal ambivalence about the bear's chances for survival.

But then two grizzly cubs (newly emerged from the den and hungry for meat as are all spring grizzlies) spot a field mouse zipping across the snow. Instantly, they -- and McNamee -- are in their element as the chase is on, and all else forgotten. "But the mouse is too quick for these still clumsy babies, scurrying down its burrow in a flash. Dig then they must, and impressively do. Sod clods fly between their little back bowed legs."

The mouse eludes the grizzly cubs, though, until the mother moves in. "She cocks an ear groundward, hears the faint rustle of the subterranean quarry, and with a single scoop of her paw brings up a hunk of turf from which squirts the mouse, straight into her jaws. Crunch, gulp, and it is gone. The cubs look on, dazzled, one lesson closer to competence."

So too will readers of "The Grizzly Bear" come away with a deeper appreciation of what it means to be a "griz," and what the survival of the largest terrestrial carnivore means to the world.