Earlier they had dragged a furry, white, thousand-pound burden onto the net. The thoroughly tranquilized adult male polar bear was breathing easily, but hardly in a fighting mood. The chopper flew away with its furry cargo dangling far beneath it, watched by a small crowd of camera-laden tourists and grateful townspeople.

The helicopter would not land until it reached a location 50 miles or so to the north. There the crew would gently lower the animal to the ground and wait nearby to protect their passenger until he was fully awake and able to fend off other bears that might otherwise take advantage of a bleary-eyed beast that had been banished to the wilderness.

This scene takes place as much as 100 times a year in the town of Churchill, which proudly claims the title of Polar Bear Capital of the World. It's right in the middle of the migration route of Ursus maritimus, the Great White Bear.

A polar bear might show up in the neighborhood at any time of the year, but in late October or early November, hungry bears hang around by the hundreds, waiting for the "freeze-up" on nearby Hudson Bay. Then they can once again pad their way out on the ice to hunt seals, which make up the favorite part of their diet.

All the town's residents have a bear story or two --- generally surprise encounters that seemed scary at the time, but that came out all right in the end. Polar bears have been known to turn over a car, and then walk away after losing interest in the game.

The town sells plenty of bear souvenirs, too. Popular are reproductions of the warning signs placed at strategic points at the edge of town. There are also two museums mostly devoted to bears and other wildlife.

Generally speaking, the animals stay beyond the town, but every now and then one decides to go for a stroll on neighborhood streets and alleys. Then the town bear patrol captures or traps the rogue explorer. Their captive gets put in the barnlike Polar Bear Jail outside of town to wait for freeze-up or else takes a copter ride immediately to other locations in the wild.

The town used to give the jailees food, but soon found bears trying to break into jail, so now captives get only water.

As much as Churchillians love their bears, they are constantly on watch, especially in the fall. Costumed children go trick-or-treating on Halloween night, accompanied by parents toting guns and rifles. The last fatal encounter of the furry kind was more than 20 years ago, but nobody believes in taking chances.

Polar bears are meat eaters, after all. Unlike more omnivorous grizzlies or black bears, they would never be satisfied with a bush full of berries or a few purloined chocolate bars.

Tourists who want to see polar bears are welcome in Churchill, so long as they follow the rules. No roads lead to the town. They come either by an all-day train ride north from Winnipeg, or via airplanes that land at a former air force base near the town. Local hotels can arrange for day trips out on the nearby tundra to see the animals.

My own all-inclusive experience was with Natural Habitat Adventures, a Colorado-based outfit, which is the largest tour operator. It offers small-group polar bear tours in October and November, two of them geared particularly to dedicated amateur photographers. These are headquartered on the tundra itself, where most of the bears gather to wait for weather cold enough to form their icy road to seal-hunting grounds.

For photo tours, Natural Habitat's accommodations are in the Tundra Lodge, a trainlike set of rubber-tired frame buildings that can be placed in the expected center of the action. Each train car holds a group of tiny rooms equipped with bunk beds, a lamp, and not much else. Still it's less primitive than some other operations, and no one had any trouble sleeping or keeping warm.

Toward one end of this stationary train is a cozy lounge equipped with a bar and a TV set, which is often playing tapes or DVDs of wilderness and bear experiences. And attached to that is the last car containing a kitchen and dining room, which serves breakfast and dinner.

Walking the open spaces between the cars provides brief, sharp experiences in Arctic air for those living near the end of the train, especially at night. Nevertheless, some stop occasionally to admire the Northern Lights, which can be dramatically colorful at these latitudes and at this time of year.

Lunch is taken out on the tundra where daily photo excursions are made in specially constructed tundra buggies. They seem like outsize school buses, but each contains a space heater, a chemical toilet, and, in one corner somewhere, a seldom touched, but always ready, 12-gauge shotgun. These vehicles lumber slowly around the landscape looking for bears. Harassing or baiting the animals is not allowed.

Photographers can aim through open windows in the tundra buggy. Hardy souls will occasionally brave the wind and cold to stand on an open back deck, where some photographers set up their tripods and telephoto lenses. Everyone hopes for the biggest prize, a full-frame photo of a sow with her cubs.

Like the hotel train, the tundra buggies are high enough off the ground so that even a standing bear cannot quite shake hands with the human cargo. They are usually more curious than aggressive, although some decide to chew on a tire now and then.

The back deck is a grating through which guests might see a really close black nose, maybe even feel the breath of a bear. But it would be a mistake to stick a finger through it. These cuddly animals with their gentle, kind faces have powerful teeth.

Natural Habitat Adventures has a close affiliation with the World Wildlife Fund. In addition to getting some dramatic images or footage of polar bears and other wildlife, their guests learn a considerable amount of northern wilderness lore, especially in the evenings before and after dinner when everyone is sitting around talking about the things they have seen throughout the day.

"Not enough people realize the dangers that modern life has placed on future enjoyment of the Arctic wilderness," said our expedition leader, Matthias Breiter. "People who have not been to the Arctic tend to see it as simply a white wasteland, and that developers won't ruin anything if they go there.

"As far as I am concerned, the entire purpose for promoting ecotourism in the Arctic is so that people can see that it needs to be protected."

Frequent bear encounters are often separated by other animal experiences, such as sightings of the arctic fox, or the small birds called the willow ptarmigan. Both creatures have coats that turn from brown to white and back again, in concert with the seasons. Snowy owls also sometimes appear.

One thing potential guests should be aware of is that no one knows exactly when the bears will be most numerous.

"The best time to come is the week before freeze-up, but no one knows exactly when that is," said Breiter. "Generally speaking that is the last few days of October and the first 10 days of November. Anything earlier, it's warmer and there's not as much snow. Anything later, and most bears have already made their way out onto the ice."

If freeze-up happens early, most bears may be gone by your arrival time.

Still, Breiter says, the company makes sure its guests have some sort of a bear experience, no matter what happens with the weather. One year they piled everyone into helicopters and found groups of bears via an aerial reconnaissance.