Firing bolt-action rifles as they ran, a dozen Ethiopian Afar nomads chased an unarmed man across this nation's main north-south highway last week and shot him in the back. He fell on his face -- wounded, not dead -- in the stones of a dried-up river bed.

Fifty miles south of the the shooting, a troop of gelada baboons, with scarlet coloring on their breasts and babies on their backs, sidled across the same highway on the same day. They scaled a steep wall of rocks while pitching stones the size of softballs at a Land Rover that lingered beneath them on the highway.

On that same highway, 75 miles south of the baboons, a hand-painted sign outside of a hamlet of stone huts, mud yards and underfed donkeys, said this: "Being a Communist is a great honor and a serious obligation."

Ethiopia, as seen last week from a Land Rover on the two-lane asphalt strip that snakes north from Addis Ababa to this lowland village, is part Marxist, part medieval, part jungle movie. It all depends on when you look out the window.

About the only safe generalization from a two-day, 450-mile round-trip to Efeson is that Ethiopia -- with 7.75 million people estimated to be in danger of starving to death -- is a nation that has taken its suffering onto the road.

The Marxist military government of Mengistu Haile Mariam began shipping famine victims south last month as part of what it called a plan to "rehabilitate" 1.5 million people. Hundreds of buses and dump trucks, crammed with emaciated peasants from the famine-crippled north, rolled down Ethiopia's Highway 1 for vacant land in the far southwestern corner of Ethiopia.

In slower transit unauthorized by the government, thousands of other famine victims -- highland farmers and lowland nomads, Christians and Moslems, Amharics, Tigrayans and Oromos -- moved both north and south on Highway 1. On foot mostly, but also on camels, mules, donkeys, cows and their mothers' backs, these refugees came to the highway not only for travel, but to peddle their possessions and beg for food.

It took a few hours, however, after leaving Addis Ababa before Ethiopia appeared other than a land of abundance. The high plateau around Addis Ababa, which had plenty of rain this year, looked from the road like farmland in western Montana, where the prairie gives way to the foothills of the Rockies. Plump cattle and donkeys had enough spunk to bite and kick each other. High-voltage power lines marched across the plateau on modern steel towers.

As a testament to the free-form art of Ethiopian driving, unfettered by speed limits, stop signs or median strips, a collision-mangled Pepsi truck lay on its side beside the road in a field of wheat stubble.

Just south of Dabra-Berhan, there was a reminder that this Highway 1 is not in Montana. A stern-faced woman with a black turban on her head, her shoulders wrapped in a snow-white gabi, the traditional Ethiopian gown, rode south on a horse festooned with red and blue feather plumes. The woman in the turban refused to say where she was going, but an Ethiopian in the Land Rover concluded that she was headed for a wedding.

A few miles beyond the woman and her horse loomed the hand-painted sign that spoke of the honor and obligation of being an Ethiopian Communist.

Ethiopia has been a Marxist state for a decade, since the late emperor Haile Selassie was driven away from his Grand Palace in Addis Ababa in a Volkswagen. In the revolution, the old feudal landlord system was destroyed and every peasant was given up to five acres of land. A peasant in revolutionary Ethiopia cannot hire another man to help plow his field; it is considered exploitation.

About $3 billion worth of Soviet-supplied weapons are now in Ethiopia, and western diplomats here estimate that about 2,500 Cubans and 3,000 Soviets are here. Mengistu left last week for one of his semiannual trips to Moscow and Soviet Bloc capitals. On the outskirts of every village along Highway 1 between Addis Ababa and Efeson are green, yellow and red bamboo arches over the road to mark the revolution.

But between the bamboo arches the revolution appeared not to have changed much in the thatch-roofed circular stone huts that line Highway 1. Women cook with open fires in the huts, as they have since the Middle Ages. Livestock remains the major measure of wealth, according to foreign agricultural experts. The government's new census, released this month, says that 88.7 percent of Ethiopia's 42 million people live on farms and small villages.

It takes about four hours of driving north, winding down off the 7,600-foot-high plateau on which Addis Ababa sits, before evidence appears on the road of a famine that the United Nations estimates has killed more than 300,000 people during the past nine months.

About 20 miles south of the troop of gelada baboons that crossed Highway 1 in the mountains above a town called Debre Sina, emaciated children began to stand in the middle of the road, holding out their hands. Famine victims lined the highway on the road south to Efeson.

They sat on the shoulders of the road beside bundles of wood they were selling for 50 each. Until recently the government did not allow peasants to peddle wood on the highways. It has been trying to discourage the deforestation that has made central Ethiopia one of the largest areas of ecological degradation in Africa. According to the U.N. Food and Agriculture Organization, 16 percent of Ethiopia was covered by forest 20 years ago; now trees cover 3.1 percent of the land.

Now the government has no time to worry about dead trees. Fleeing drought, Afar and Oromo nomads and their herds have for two years been migrating west out of the Awash Valley into already overpopulated northern Shewa Province. They have begun fighting among themselves for grazing space in an area that in the past year and four months had had almost no rain.

The Afars who last week shot a man beside a river bed south of a town called Jahewa may have been settling a dispute over grazing land. According to U.N. officials, there have been such incidents in the area. But the reason for the Jahewa shooting remains unknown. The driver of the Land Rover, in front of which the shooting occurred, refused to linger for an investigation.

Along the road were a few Afars, known here for their pride and their long knives called giles. Yet as cars passed by them, the Afars held up their knives for sale.

Finally, at Senbate, about three miles north of Efeson, Highway 1 cut past a famine feeding center -- the southernmost one of the 200 or so such places in Ethiopia.

Although only eight weeks old, it was hauntingly similar to larger camps up north: overcrowded, understaffed and almost silent but for the coughing and crying of children.