Standing on a knoll in the foothills of the Brooks Range, 120 miles above the Arctic Circle, Kenneth and Caroline Frank point out the first caribou of the fall season drifting by in groups of two and three. Though Kenneth is a hunter, he restrains himself as the animals pass, some no more than 25 yards away. "We should wait," he explains to my wife and me, friends from another culture. "There will be more in a day or so."

The Franks are Gwich'in Athabascan Indians--members of a tribe that has existed here for thousands of years--and letting the lead caribou move on is an ancient custom; otherwise, the animals might turn tail and alarm the rest of the closely trailing major herd.

Tens of thousands of caribou soon will pass through this treeless terrain above the small community of Arctic Village. The animals have spent the summer on their calving grounds along the Arctic Ocean, and now they are heading for wintering grounds in Canada. For the Gwich'in, the caribou's arrival is a major event that sends hunters scurrying into the hills. Many in this tribe of about 5,000 members--who live in a dozen villages scattered along the herd's migration route in Alaska and Canada--still depend on stores of caribou meat for full stomachs when the temperature drops to 70 degrees below zero and game is not moving. "The caribou are the Gwich'in's bison," says Gwich'in Donna Carroll.

These days, the herd's return is cause for even more celebration than in the past: With lobbying and publicity, the Gwich'in have been working to thwart ongoing attempts by the oil industry and some lawmakers to drill in the coastal plain of the Arctic National Wildlife Refuge (also known as ANWR). Not only does the wildlife-rich plain hold some of the greatest biological diversity in the entire Arctic, it is the main calving ground of the Porcupine caribou herd (named for a river it crosses during migration). Convinced that drilling there would harm the caribou, the Gwich'in see every successful fall migration as evidence their efforts have worked--so far. "If we are to save our culture and prevent social ills," says Gwich'in minister Trimble Gilbert of Arctic Village, "we must preserve the calving grounds."

Few outsiders visit the Gwich'in, and even fewer spend more than a few days here. But my wife Jane and I have lived in this land of bogs and meadows and mountains. Between 1991 and 1993, I taught high school as a generalist in four of Alaska's seven Gwich'in villages, mostly in the summer but once during the long winter months. Since then, we have returned to the Arctic several times, and we have traveled widely through the land of the Gwich'in. The more time we spend here, the more we want to learn about these people whose lives have profoundly moved us.

Land claims: In 1971, the neighboring villages of Arctic Village and Venetie (located 70 miles apart) elected not to participate in the Alaska Native Claims Settlement Act (ANCSA). The act settled most of the state's tangled aboriginal land claims and allowed the Trans-Alaska Pipeline to be built. Under ANCSA, almost all Alaska Natives--including Indians, Aleuts and Eskimos--became members of village and regional corporations that divvied up almost one billion dollars and 44 million acres of land. But not the residents of these two far-north villages.

Instead, these Gwich'in turned down a share of the money and retained their original land claims--more land than they would have received under ANCSA. They still live a subsistence lifestyle that is among the most traditional of any Alaska Natives--or of any Native Americans, for that matter. Though the Gwich'in rely largely on caribou, they also fish and hunt moose, sheep and smaller game. Not so long ago, the residents of Arctic Village and Venetie preferred little contact with the outside world. But then they decided to fight for the Porcupine herd's calving grounds, and tribal chiefs decided in 1988 to create the Gwich'in Steering Committee to publicize the tribe's existence and its reliance on the caribou.

Though they live in log cabins, use wood stoves for heat and sometimes must chop holes through 3 to 5 feet of ice in the East Fork of the Chandalar River to reach water, this group of about 350 is proud to have retained possession of its ancestral hunting lands. And the two communities are joined by most of the inhabitants of the other five Alaska Gwich'in villages in denouncing efforts to open the Arctic Refuge's coastal plain to drilling.

"Our children draw pride from the caribou," says Caroline Frank. "The herd reaffirms our way of life; it tells them they are the descendants of some of America's strongest hunters." Adds Kenneth Frank, her husband, "Our culture is thousands of years old. Is just a few years of oil worth all that? Or will the white man always want to destroy the land and the most beautiful animals on it?" Caroline is one of the first Gwich'in Indians to complete a four-year degree and return home to teach. Kenneth is a substance-abuse prevention worker.

For a time, the effects of alcohol were so devastating that village members voted 20 years ago to make Arctic Village dry. "We're enjoying ourselves without alcohol," says Kenneth.

Epic migration: The night after we see the first caribou pass by, we return to Arctic Village to wait for the main herd, and we dream of the days ahead. Caribou! Magnificently antlered animals. Great aggregates of tawny beasts, flaying the tundra with their hooves, white chests glimmering in endless Arctic days, streaming along the flanks of Datchanlee Mountain. When the herd migrates, the Earth pulses. In peak years, the central, densest grouping of animals in the 160,000-member Porcupine throng can approach 120,000. Out of Alaska's 31 caribou herds, this one is currently third largest.

In winter, this herd tends to scatter on both sides of the U.S.-Canada border. In April, the herd begins its 350-mile spring trek, traveling through stunted stands of black and white spruce, swimming through raging rivers choked with ice and threading mountain passes to reach the coast. How the animals do all this with such an unerring sense of direction is not clear. They arrive on the coastal plain just as all the cows are ready to give birth. Within days, thousands of new calves enter the world and spring over melting snowbanks as they follow their mothers in search of food.

Scientists have been monitoring the Porcupine herd's habits since 1972, verifying what the Gwich'in have long known: The coastal plain is key to the herd's reproduction. Biologists have identified a 740-square-mile region within the Arctic Refuge as the herd's "core calving grounds." The caribou almost always deliver their calves on these grounds, and even if the animals calve elsewhere, they always use the plain as a post-calving nursery, moving there as soon as the calves can walk. "The grounds are sacred to us," says Gwich'in Jonathan Solomon. "In all my 64 years, I have never been to the calving grounds. That land there is very fragile, so we stay away."

At a time when other areas may remain locked by winter, here snows generally recede, followed within a few weeks by a spring so brilliant with greenery it can dazzle the human eye. The green is flanked on one side by an ocean dotted with chunks of ice and on the other by the towering, snow-covered mountains of the Brooks Range.

Predators such as wolves and bears tend to stay in the foothills, and the plain is a source of nitrogen-rich willow shoots and the flower heads of cotton grass. The nitrogen is important to the caribou for the production of protein-rich milk. The coast also offers the animals a sanctuary from the torment of thick clouds of mosquitoes and parasitic flies. Winds howl off the Arctic Ocean, forcing insects to the ground. If the winds fail, the caribou sometimes swim into the water, or crawl onto ice or snow, for some relief from the insects.

Caribou and oil drilling: One hundred miles to the west, the Central Arctic caribou herd, about one-tenth the size of the Porcupine herd, has contended with oil development at Prudhoe Bay on the northern edge of that herd's range. Even though the herds differ in size and the Porcupine herd migrates as much as four times farther, might these other caribou hold clues about the potential effects of similar disruption on the Porcupine herd?

As anyone knows who has seen photographs of the Central Arctic herd grazing next to the trans-Alaska pipeline, in some circumstances the animals coexist just fine with big human-made structures. In fact, the herd's size increased dramatically under the conditions of the early 1970s, when Prudhoe Bay was first developed--conditions that included moderate winters and a decline in predation. Ken Whitten of Alaska's Department of Fish and Game, who has studied caribou for more than 20 years and authored many scholarly papers about the two herds, notes that the original Prudhoe complex "was constructed in a little-used portion of the Central Arctic herd's calving grounds, and many cows were able to shift to undisturbed calving areas."

In the late 1980s, however, oil development spread into more heavily used calving areas, and caribou moved to less desirable areas. Now the Central Arctic herd's numbers have fallen from a high of 23,400 in 1992 to 18,100 in 1995, the date of the last census. "The population drop has us concerned," says Whitten, "because it all occurred among the portion of the herd that uses the oil-field area. The portion of the herd that does not use the oil field has continued to increase." Biologist Don Russell, Yukon manager of the Canadian Wildlife Service, says he "can accept that oil development is the cause of the Central Arctic herd's decline."

As for the implications for the Porcupine herd, studies in the peer-reviewed scientific literature indicate that development on the Arctic Refuge's coastal plain would cause major, irreversible changes in the Porcupine herd. Such work could include construction of oil rigs, gravel pads and gravel roads--as well as operation by hundreds of workers--in the calving grounds.

Russell, who has studied the Porcupine herd for 24 years, says his studies of the animals' protein needs provide a link between disturbances and health problems, including calf mortality and pregnancy failures. "If cows don't get enough protein to gain muscle over the summer, then up to 80 percent of their calves die," says Russell. "The cow will stop producing milk for her calf if her own survival is threatened. As well, if she can't gain enough fat over the summer, she has a slim chance of getting pregnant in the fall." Russell maintains that nursing caribou cows must have unrestricted access to the fresh green plants in the months of June and July.

According to Arctic Refuge biologist Fran Mauer, who has studied the refuge since 1981, the effects of oil development could be much more devastating to the Porcupine herd than it has proven to be to the Central Arctic herd. "You've got a different situation" says Mauer. "The herd is much larger, and the mountains much closer to the ocean, all of which serves to compact further the space available at the calving grounds. As a result, losses to the Porcupine herd from oil development could be greater."

"That's what we're concerned about," says Jonathan Solomon. "If caribou numbers fall, it may change the herd's migrational pattern, because smaller groups have different nutritional needs. Caribou won't migrate past our villages. What will we eat then?"

The hunt: For now, the Porcupine herd continues to move just as it has for 30,000 years. When the calves are about five weeks old, the caribou leave the coastal plain. Usually they take off in late July, for even in mid-summer, winter is not far away. Sometimes isolated animals drift south, but generally, the herd moves in a way that defies the imagination. One day the grounds swarm with life; the next day, nothing.

After several weeks, the herd passes Arctic Village, and hunters disperse. Among them are many of our friends, including village minister Trimble Gilbert and some of our former students, like 16-year-old Robert Lee Sam, who began hunting when he was 10. When we were teaching, we knew why Robert wasn't in class on certain fall days--and how much Moses Sam, his grandfather, relied on him for supplies of meat.

Kenneth and Caroline Frank join the exodus. After loading gear and packs onto the bed of a trailer pulled by a four-wheeler, they ascend a rutted trail on their way up Datchanlee, which means "above timberline." After establishing their camp, they move to a knoll from which they peer out over the treeless landscape. About an hour later, the couple spots a small group of caribou. Kenneth moves forward, stalking his quarry--advancing when the animal lowers its head to graze, freezing when the caribou pauses to examine its surroundings.

Soon Kenneth closes on a large bull. He is a marksman, and the bull dies quickly. Kenneth then stands motionless, paying his respects. According to traditional Gwich'in beliefs, every caribou contains a bit of the heart of every human, and every human a bit of the caribou heart. Many hunters offer a prayer of thanks to the caribou and sometimes eat a portion of the raw caribou heart.

After field dressing the caribou and cleaning the kill site out of respect for the animal, the Franks load more than 200 pounds of meat onto the back of their four-wheeler and grind their way over fields of tussocks back to camp, where they begin drying the meat. Later, as the day progresses, the couple kills four more caribou. From each animal they remove the kidneys, liver and heart. They also remove the stomach and small intestine, which the Franks think are the best parts--and which they later persuade us to eat. We smile as we munch, nodding our heads up and down, agreeing that there is nothing better in the whole wide world than fried caribou intestine.

Absolutely nothing goes to waste. Some tribe members still tan hides, including Kenneth, who has relearned the skill. He will later fashion the tanned hides into clothing. Out of respect for traditional ways, not even the hooves are discarded, for in more desperate times, the Gwich'in boiled them to extract a broth. Those memories remain deeply etched.

Celebration: To ensure that such excellent hunting will persist, a Gwich'in Caribou Management Board has drawn guidelines. The Board suggests that a hunter limit himself to five caribou during any given outing, in the belief that five is a reasonable number to be properly butchered and transported. Other rules prohibit hunters from feeding caribou meat to dogs, with the exception of bones, scraps or unused meat.

Not all the caribou meat remains in the village. Some will be traded to friends in other villages for salmon, moose steaks, or even beaver. Or meat might be whisked by bush plane to relatives living in other villages or urban areas such as Fairbanks--as it sometimes is to Kenneth's father, Hamel, who is sick, but who says he always gets better when he eats caribou.

About a week after the first major outing, hunters return and plan a potlatch to celebrate their successful kills. Gathering near a community center, villagers kindle several fires over which they suspend ribs, filleted meat and caribou heads. The heads brown quickly, and soon rich juices cover the meat, which falls away from the skulls. Later, Trimble Gilbert will bring out his fiddle, and families will move indoors to the community hall, where celebrants will jig through the short night and into the dawn of a new Arctic day.

Jane and I attempt the jig and then stand back with Kenneth and Caroline to watch the children as they perform a caribou dance. Some are clad in caribou skins, and their movements are reminiscent of white-chested caribou prancing through the muskeg. The dance echoes, too, the age-old drama that binds hunters together with a massive herd that still crosses an international border, feeds a dozen villages and piques the imagination of so many others.

The next day we climb Datchanlee to watch the great aggregates of tawny beasts slice their way, once again, through the long Arctic day.

Freelance writer and photographer Bert Gildart lives in Bigfork, Montana. This is his first article for National Wildlife.