Alejandro Sarete is up before dawn, slipping into the windswept darkness looking for wolves and coyotes prowling among his flock.

With the herd accounted for, he has breakfast in his tiny home -- a metal camper too small to stand up in, with a rattling washbasin and a haunch of raw lamb hanging from its side. An old stove provides heat, a lantern gives light, and a lone portrait of Peruvian singer Anita Santivanez offers the only decoration.

Today, Sarete will help bring thousands of sheep out of the high desert, branding and penning them up here near the town of Kemmerer in southwest Wyoming. Then the father of three, who left his children in Peru, will take another herd into the state's vast interior. It is a timeless task, a steady rotation of sheep that marks his days and structures his life.

For the past decade, ranchers across the West have come to rely almost entirely on Peruvians such as Sarete to tend their sheep. The rugged South Americans have a rich herding tradition, are used to harsh weather and are willing to work for low wages in one of the nation's least known but most demanding occupations.

"In Peru, I might make $5 a day if I'm lucky," said Sarete, 38, a stoic man with a smooth face and stocky build. "I have used the money I make here to buy a tractor and a bull back home."

Sheepherders arrive on three-year visas with wages set by each state. In Wyoming, the pay is $650 a month plus food, airfare, clothes and lodging. They labor 365 days a year and are on call around the clock. Living in tents or campers, they often spend weeks alone with their grazing animals. There are no televisions, no telephones and radio reception is spotty.

Western Range Association, the biggest provider of foreign workers for U.S. sheep ranchers, said 82 percent of its 800 herders are Peruvian, 12 percent are Chilean and the rest mostly Mexican.

"We tried Mongolians, but it didn't work out. There was too much of a language barrier," said Dennis Richins, executive director of Salt Lake City-based Western Range. "Then we started bringing in Peruvians. They were used to being in the mountains and used to being around sheep."

Before the Peruvians, Basques from Spain along with Mexicans made up the majority of herders. American sheepherders, common until the 1950s, are rare.

"I think the last American I had was here for about two weeks," said Truman Julian, a fifth-generation rancher who has 10,000 sheep, one of the largest herds in Wyoming. "He thought it would be glamorous, like being a cowboy, but he soon realized it wasn't."

Sheep need careful tending because they are on the menus of so many predators, including bears, coyotes, mountain lions and wolves. "Cows you can let out and forget about," Julian said.

As he spoke, the thump of hoof beats rose in the distance. Moments later, chaos erupted. More than 2,000 sheep charged down the parched hills, encircled by barking border collies. Peruvians on horseback galloped in behind them. Herders whooped loudly, frightening and funneling the wooly mob through a narrow gate.

"These guys are the toughest of the tough," said Julian, who employs the men. "Their whole lives are dedicated to these sheep. If they left, we'd be finished."

Herders are the country's solitary nomads, following their sheep and constantly looking for greener pastures. They come together at certain times of the year when flocks are sheared, branded, medically checked or shipped for slaughter. On such occasions, their tents and campers form tiny hamlets where the men pass the nights talking of home and listening to Peruvian music.

In Pomeroy Basin, a swath of sage and dun-colored hills, the animals have come to be branded and have their teeth checked for wear. Sarete and six other herders pried open each sheep's mouth, looked deep inside, then sent it on its way.

Back home, such work could be had for only a month or two each year.

"Of course, I'd love to be in Peru," said Sarete, who has spent the last decade working as a herder. "It's hard to have a family there and work here. In three years, I'll go back to Peru, then come back here."

Black clouds gathered, obscuring the sun and turning noon into something approaching twilight. The workers, cold and dirty, broke for lunch and headed for a pair of campers brought in from the desert. The aging shelters measured about 14 feet long by 5 feet high and sat atop wooden wagons pulled by horses.

Four herders crammed themselves into one, huddling around a stove waiting for coffee to boil. "Peru looks like Wyoming, but it isn't as cold," said Michael Tacza with a slight shiver.

The others, bundled up to their chins with two or three hats on, nodded numbly.

"If I had money, I would have studied architecture," said Tacza, 21. The men smiled as they considered the vast gulf between designing buildings and herding sheep.

"I'd like to be a veterinarian," said Genaro Bilches, 40.

Bonito Bruno, 35, thought a moment.

"I'd like to play the saxophone," he said.

Everyone laughed.

Many of the herders come from the village of Huancayo in central Peru. They speak Spanish and Quechua, an indigenous language. The ranchers also speak Spanish.

On rare occasions when they are given a day off, the workers might take a bus to Salt Lake City to mingle with other Peruvians, some of whom were herders before fleeing their employers to work illegally in the city.

Herders deserting their posts have become a problem. Julian, who employs 19 Peruvians, has lost four men this year and reported them to immigration authorities. They have not been found.

"We pay for their clothes, shoes, food, air tickets, workman's compensation and then some jump on us," he said. "I lost five at one time three years ago."

Nationwide, Texas produces the most sheep followed by California and Wyoming, according to industry officials. Ranchers say labor problems, drought, predators and foreign competition keep them awake at night.

In summer, sheep graze in the mountains; in winter they are brought to the desert. Ranchers travel with the herds, sometimes staying with them three or four months each year. Julian, 59, often sleeps in a tepee among his sheep.

He concedes it is a hard life, but one offering a kind of independence increasingly scarce in modern society. And for him, it keeps alive something ancient.

Some Peruvians have been the targets of mistreatment, according to officials. Some are not paid what was promised; others are left alone for months or forced to do work unrelated to herding.

"In Utah, we have heard of people who come to be sheepherders and end up working in rock quarries," said Marita Landaveri, Peru's consul general in Denver. "Sometimes ranchers are delayed in bringing them food and water. Many times they are charged for food."

State inspectors check out living conditions each year. Officials of Western Range Association, which imports workers, said that if they receive complaint, they contact the employer. If they get two complaints, they stop sending workers to the rancher and expel him from the association.