The American bison, commonly called the buffalo, is the largest American land animal and one of unpredictable temperament.

A fully mature bull is a massive animal standing six feet at the shoulder, perhaps 10 feet from muzzle to rump, and will weigh just short of a ton. In rut it is afflicted with a mindless fury.So naturally I felt a certain unease when a band I had been photographing wandered off a hillside and into our immediate vicinity, blocking the road ahead.

They were part of a larger herd of 400 bison, which roam Montana's National Bison Range - a 19,000-acre reserve in the Flathead Valley, administered by the U.S. Fish and Wildlife Service.

Earlier, my wife and I had stopped at the visitors center where we were supplied with brochures and given the option of two self-guiding tours.

One was a 20-minute loop adjacent to the museum, known as the Buffalo Prairie Drive. On this drive, bison and elk can be seen in enclosures, or so-called demonstration areas.

The other snakes its way across hilly grasslands and through the park-like stands of pine and fir atop Red Sleep Mountain.

Here there are ample opportunities to spot not only bison in the wild, but elk, mule deer, pronghorn antelope and bighorn sheep as well.

It takes at least two hours to complete the 19-mile drive. The road is one-way, graveled and beset by switchbacks and steep grades. We were told it was OK to get out of our vehicle, but warned to stay by the car and to watch for rattlesnakes.

We had covered only about five miles of the drive, spotting a number of pronghorns along the way, when we were caught in the "buffalo jam."

A willow-choked creek on one side of the road blocked the band and they milled about not knowing which way to turn.

There were smaller cows, still suckling yearling calves, "spike bulls," those less than four-years-old with smooth clean horns, and a few mature animals, shading from a light brown at the hump to a dark brown, even black at the head and hind quarters.

It was late summer, near the end of the rutting season and a couple of young bulls began a shoving match as they tested their strength against the day when they might challenge the leader.

In 1962, in the Black Hills of South Dakota, I had photographed a similar herd from the back of a pick-up truck. A story going the rounds then was of a couple in a Volkswagen that had somehow enraged a bull. The animal had

hooked the vehicle and upended it.

Apparently these bison were used to cars and they paid scant heed as I edged through the band as one would drive through a herd of cattle.

The short grass that carpets the National Bison Range, the bluegrass and fescues, is the same as that which nourished the great herds observed by Lewis and Clark in 1805.

" . . . this scenery already richly pleasing and beautiful was still farther heightened by immence herds of Buffaloe, Deer, Elk and Antelopes . . . " Meriweather Lewis wrote in his journal.

"I do not think I exagerate when I estimate the number of Buffaloe which could be comprehended at one view to amount to 3,000."

It's believed the American bison migrated from Asia in the early Pleistocene, perhaps a million years ago, trailing across the trans-Bering land bridge.

Although no one knows exactly, 15 million of these animals may have grazed the Great Plains through the first half of the 19th century. Plainsmen told of riding 100 miles through one herd and another estimated the size of a herd at 70 by 30 miles.

To the Plains Indian, the bison was life itself. The hide clothed and sheltered him and the "buffalo chip" was the firewood of the treeless plain.

Although the hump and ribs were considered delicacies, lesser cuts were not spurned. Even the intestines were eaten. No wonder the Indian went to war when the whites began perhaps the most relentless slaughter of a wild animal the world has ever known.

They were gunned down by the millions, by settlers and soldiers alike. Sometimes only the tongue was taken. Often the entire carcass was left to rot.

The construction of the railroads across the plains after the Civil War lent a furious impetus to the killing.

The promise of profits for meat and hides drew the professional hunter by the thousands, carting his favorite weapon, the Sharps .50 calibre rifle shooting 125 grains of powder and 600 grains of lead.

Steadied by a dead-rest, the accuracy of the "Buffalo Gun" became legendary. It was not out of the ordinary for one hunter to kill 200 buffalo in a "stand," dropping them one by one, and so far away the scent could not be detected by the milling herd.

By 1890, there were perhaps 20 bison in the wild of the U.S., a handful in private hands and an overlooked herd of 600 in Canada.

These days, the vanishing American buffalo has made an amazing comeback. There are possibly 85,000 nationwide, on such reserves as the Custer State Park in South Dakota, here at the National Bison Range and Antelope Island in Utah.

Many are also in private hands, raised as meat animals. It seems buffalo steaks and buffalo burgers are increasingly in demand.

The herd that now grazes the National Bison Range was the result of a fortuitous hunting expedition by Pend d' Orille Indians in 1873, when one Walking Coyote retrieved three bison calves from the Flathead Valley.

Thirty-four descendants of those animals were purchased in 1909 with $10,000, raised by popular subscription by the American Bison Society. Those bison, with seven donated animals, were released onto the newly established range October 17, 1909.

Faded black and white photographs of these bison being unloaded from railroad cars hang on the wall of the Bison Inn, a modest cafe in Ravalli, just south of the range. You can also order your bison burgers here.

From the summit of Red Sleep Mountain we had a fine view of the Mission Range, their peaks thrust high above the patchwork of farms dotting the upper Flathead Valley.

Beyond the summit the narrow graveled road descends abruptly in a series of hair-pin curves and there are no guard rails.

It was the place where we were told to be on the lookout for a cranky bighorn ram that had a penchant for smashing into cars. We finally spotted it, but too far away for a decent look. On a tour of the bison range, a good pair of binoculars is a must.

Mission Creek slices through the northern end of the preserve enroute to the Flathead River, its riparian environment frequented by white tail deer along with a host of smaller animals and song birds. With a proper license, you can fish this stream.

In the winter, the prairie habitat is surprisingly free of drifts which blanket the nearby hills. The immediate area, in fact, is known as Montana's "Banana Belt."

Even the harshest of winters hardly exist for the bison, protected as they are by great shaggy coats and their ability to paw through snow to reach the tender shoots of grass.

Pronghorn in turn find shelter in the brushy draws, while wind ducks congregate along Mission Creek.

Late spring is the best time to see the display of wildflowers. Paintbrush, clarkia, patches of balsamroot, larkspur, yellowbells and asters. By June, the bitterroot, Montana's state flower, carpets the hillsides in a gaudy display of yellow.

The Ninepipe National Wildlife Refuge is hard by the reserve. It lies in glacial "potholes" scooped out of the largest breeding populations of redheaded ducks on the continent along with a sizeable population of Canada geese.

The entrance to the National Bison Range is at Moiese, off Montana 212 and 37 miles north of Missoula via U.S. 93.

A day-use picnic area and nature trails are near the entrance. A handsome visitors center/museum marks the end of the paved road. Here you can browse through exhibits tracing the history of the bison, its near extinction and its present recovery.

The Red Sleep Mountain drive is closed in the winter. Otherwise the reserve is open year round. Bicycles and motorcycles are prohibited on both drives and trailers must be left behind when touring Red Sleep Mountain.

(B) Frank Jensen lives in Salt Lake City and is a frequent contributor to the Deseret News Travel Section.