For 363 days of the year there is little to distinguish Surin from any other town in northeast Thailand, a region noted chiefly for its cattle-raising, tobacco and silkworms. But for two days in late November, Surin and its 30,000 inhabitants are transformed by an invasion of elephants and tourists. The occasion is Surin's annual elephant roundup.

A sort of elephant rodeo, the roundup is not, contrary to what the Thailand tourist bureau says, "the most spectacular show on earth." In size and spirit it is more like a country fair that brings together the region's working elephants and their handlers.

It is good, clean family fun and -- in addition to droves of Japanese, German, French and American tourists -- it attracts thousands of Thais from neighboring provinces. Some of the men wear cowboy boots.

One of the charms of the roundup is the unexpected. For example, a special overnight train bringing 280 foreign tourists from Bangkok was an hour late. As was to be expected, the fried eggs were stone cold when the sleepy-eyed visitors sat down to breakfast at the local high school. But nobody had expected the orange juice to be hot.

The unexpected also enlivened the opening "massed procession" of 100 elephants. A female elephant became so agitated that she bolted. For a moment it looked as though she might inadvertently trample a couple dozen spectators, but other elephants, skillfully handled by their mahouts, intervened to save the day.

But that incident was nothing compared to what happened during the Vietnam war when a planeload of GIs flew here to attend the roundup and could not find the airstrip. the reason was that it was covered with elephants. After the plane had buzzed the airstrip for the third time, the alarmed elephants took off in a cloud of dust. That ended the roundup.

Surin residents have mixed feelings about the roundup. With traditional Thai hospitality, shopkeepers put out buckets of water so that the elephants can cool themselves as they stroll through town. But they have not forgotten what happened last year when an elephant, pained when a pedicab ran over its toe, charged through the narrow streets knocking over everything in its path. One girl fell off the elephant. A second girl fainted but somehow managed to stay aboard until the beast could be stopped.

By that time, however, the excitement had spread to other elephants. The results was that police ordered all elephants from the town.

Obviously, the elephant roundup is not without hazzard, a fact noted by the tourist brochure with these words: "Please don't get too close to the elephants as the weather is hot and they are apt to get angry. Also, please refrain from pulling the hair from the elephant's tail."

Despite that warning, one of the features of the roundup is an exhibition in which a dozen or so people lie flat on the ground while a succession of trained elephants walk gingerly over them. Several of the volunteers were teen-age foreigners.

"Actually, there is virtually no risk since an elephant will not knowingly step on anybody," said Richard H. Johnston, a Canadian missionary who with his American wife has lived in Surin for 26 years. Johnston was asked to do an English language commentary on the roundup when it was first held 19 years ago, and has been on the job every year since. As a result he has become something of a local expert on elephants.

"I'm convinced that the elephants get as much fun out of the roundup as the people do," Johnston said, a statement that might be dusputed by the elephants, who have to do most of the work.

It is beyond dispute, however, that elephants do have fun. Another missionary swears he has seen elephants toboggan down an embankment into a river on the Burmese border.

"Elephants are smart," Johnston said. "They can learn at least 30 spoken commands and they respond to any number of body signals."

Nobody knows where the Suay came from or when they arrived in this part of the world, although it seems certain that they were here before the Thais. They have no written language, but Johnston, in a sense, is seeking to correct that by creating one so that he can translate the Bible for them. Johnston estimates that there are 180,000 Suay in Surin province.

What is known about the Suay is that traditionally they have raised, captured or trained elephants. "You'll find them wherever in Thailand there are elephants," Johnston said.

The Suay have not only taught the elephants how to play soccer -- after a fashion -- but have also schooled them in the bottle race, in which a given number of elephants pick up a series of bottles set up at intervals. Once an elephant has a bottle firmly in its trunk, it races back to the starting point, drops it and runs back to get the next bottle. The first elephant to collect all the bottles is the winner.

Another feature of the roundup is a tug-o-war between an elephant and from 70 to 100 muscular men.

The elephant always wins.

But mechanization and vulgar commercialism have overtaken this noble beast that once helped shape Thai history. Although some elephants are still engaged in honorable labor in the teak forests of northern Thailand, they are known primarily as a tourist attraction. Accompanied by their tribal keepers, they have invaded Bangkok during the last year, contributing to the most notorious traffic jams in all Asia as they compete with 70,000 cars and a wild assortment of other vehicles. Their mahouts charge 50 cents for a ride.

"No matter what," a Bangkok policemen said with a sigh, "the elephant always has the right of way."

Elephant lore is part and parcel of the mythology and history of Thailand. Erawan, the mythical three-headed elephant, is the name of one of Bangkok's leading hotels. The Bangkok telephone directory lists 20 companies with the name Erawan.

But it was the warior elephant that won Thailand its greatest glory. They were the tanks of their day. For three centuries, from 14th to the 17th, elephants were the backbone of an awesome Thai military machine that laid waste to its neighbors, Burma and Cambodia. One of the most famous battles in Thai history took place in 1592 when King Naresuan the Great, mounted on a superb warrior elephant, killed the Burmese crown prince and regained Thai independence.

The last battle in which elephants played a major role was fought in 1945 during the reign of King Rama III when a Vietnamese army invaded Cambodia, then a Thai vassal state. The Vietnamese captured Phnom Penh (does all this sound a little familiar?), but when they moved westward they were defeated by a Thai army spearheaded by battle elephants.

King Mongkut though so highly of his fighting elephants that, as a matter of historical record, he offered some to President Lincoln during the Civil War. Lincoln graciously declined, saying the American climate was not suitable for elephants.

Although machines are much more efficient, Thailand maintains a task force of 100 elephants to work in the timber industry.

"This estimable practice has become a national art and heritage to be preserved for posterity," said Dr. Amnuay Corvanich, head of the Forest Industry Organization, a government agency. To this end the agency founded a training center for young elephants at Lampang, in northern Thailand, in 1968. Under their mother's care, young elephants begin their training at age 4 or 5. They are ready for work at the age of 9 or 10.

Corvanich, an acknowledged elephant-lover and an expert on the beasts, says that the average elephant can haul about half its body weight, which is about four tons for the average male. Because they tire quickly, especially in hot sticky weather, today's elephants work a sort of union shop routine: four or five hours in the morning with afternoons off, three days work and two days rest. They also get a three-month summer holiday when they do not do any work at all.

Although normally amiable and gentle, elephants get nasty and dangerous during the mating season, a period more formally known as musth. The male, according to Corvanich, is more excitable than the female and frequently becomes hostile and agressive.

Trainers have discovered that special care, coupled with 30 to 40 melons a day, helps the elephant recover from musth and speeds his return to work. Indeed, according to Corvanich, a combination of hard work and diet can prevent musth.