A YEAR ago, as chill Mongolian winds heralded winter in the dusty garrison town of Datong, peasants living on surrounding plains saw something strange: Snakes, normally hibernating by late October, began streaming out from their hollows in the yellow, loess soil across four counties.
Within days, on Oct. 19, 1989, an earthquake measuring 6.1 on the open-ended Richter scale struck the Datong area, 130 miles west of Beijing.
In China, a country rocked by some of history's most catastrophic earthquakes, seismologists are studying abnormal animal behavior like that reported near Datong as a warning sign of imminent temblors.
Critical to this unusual forecasting method are the keen eyes and horse sense of tens of thousands of Chinese peasants, who have been mobilized to look out for odd activities by pigs, dogs, snakes, rats, and dozens of other beasts.
``Watching animal behavior can help us make the determination shortly before the quake,'' says Jiang Kexun, deputy director of the Earthquake Monitoring Department of the State Seismological Bureau. The bureau combines animal observation with seismographic data and other standard monitoring techniques, such as gauging changes in groundwater, Jiang says.
Government seismologists are convinced that since ancient times odd animal signs have presaged earthquakes in China, where 60 percent of the territory is prone to shocks of more than 6 on the Richter scale.
``This is a truth of Chinese history,'' says Chai Boping, propaganda director at the seismological bureau in Beijing.
As early as AD 650, Tang Dynasty scribes wrote that ``rats gathered on the streets whimpering before the earth split apart,'' according to official accounts. China pioneered the recording of earthquakes and is believed to have invented the seismograph in the first century.
But it was only during the radical Cultural Revolution in 1966, when frenzied dogs and rampaging pigs reportedly augered a 6.8 quake in Yunnan Province, that Premier Zhou Enlai ordered Chinese seismologists to begin setting up a nationwide network to gather data on animal reactions before quakes.
The reported observations that followed were striking.
On the morning of July 18, 1969, five hours before a 7.4 magnitude quake in the Bohai Sea, an earthquake-monitoring group in the eastern port city of Tianjin reported bizarre behavior among 36 species of animals at the Tianjin Zoo, say official accounts.
``The giant panda stands transfixed, holding its head with its two front paws and making sounds as if frightened,'' the report said. ``The northeastern tiger is listless, lying on the ground without moving its tail. Deer bolt, leaping about endlessly, swans refuse food, and parrots make strange sounds.''
ANIMALS also reacted before the massive July 28, 1976, earthquake that decimated the northeastern city of Tangshan, killing at least 250,000 people, officials say. Peasants in nearby villages saw flocks of hens - necks stuck out - running madly around farmyards. Large groups of rats gathered under rooftops, scurrying to and fro squeaking strangely, they say.
WESTERN seismologists, however, remain skeptical of China's claims about the effectiveness of watching animals to predict quakes.
They acknowledge that animals could respond to some gases, sounds, vibrations, and other physical changes created by the shifting and squeezing of underground rock before earthquakes. For example, hibernating snakes have been forced out of their holes in winter and frozen after rising gases displaced some of the oxygen in their dwellings, they say.
But scientists in the West hold that far too little is known about what causes the animal reactions. They question the accuracy of reports on animal behavior by Chinese villagers and local officials, who are under political pressure to forecast earthquakes.
Some believe that China's promotion of the animal observation technique in the late 1960s and '70s reflects the rejection of Western science and glorification of peasant know-how that was rife during Mao Zedong's cultural revolution.
``The Chinese have failed to convince [Western scientists] that animal misbehavior should be accepted as an earthquake prediction method,'' says John Armbruster, a seismologist at Columbia University's Lamont-Doherty Geological Observatory in Palisades, N.Y.
Undeterred by the Western doubts, Chinese seismologists are attempting to pinpoint what changes before earthquakes make animals react and why, Mr. Jiang says.
The government is operating more than 10 seismological research centers to raise animals and analyze any abnormal behavior before earthquakes. Since 1987, the research farms have collected data mainly on domesticated animals such as livestock, chickens, dogs, pigeons, fish, and rabbits.
Aided by electronic instruments installed in sheds, pens, cages, and sties, scientists on the farms record animal noises. The data are fed into computers and analyzed to gauge abnormal behavior.
Preliminary findings have led Chinese seismologists to link unusual animal reactions to four main phenomena that occur before earthquakes:
Low- and high-frequency sounds produced by shifting faults. Some of the sounds are inaudible to man but can be heard by animals.
Gases emitted by shifts in the earth and ground water that are sensed by some animals. Chinese seismologists have long focused on the escape of gas, or ``qi,'' from below the earth in explaining earthquakes.
Changes in earth temperature and magnetic fields.
Chinese seismologists admit that they are only beginning to understand the complex interreaction of animals and earthquakes.
``Observing abnormal signs in animals is very promising scientific work and should be stepped up,'' says Jiang. China, currently the leader in the field, hopes to cooperate with other countries in advancing its research, he says.
Meanwhile, China has mobilized its huge, agrarian population to watch for strange animal behavior and help alert professionals at 400 monitoring stations to coming earthquakes.
Using simple propaganda tools, the country has recruited tens of thousands of peasants - or one or two for every village in earthquake sensitive areas - to watch for odd signs in animals and other clues of seismic activity.
The government has distributed fans to peasants nationwide, illustrated with rearing horses, leaping fish, and roosters perched in trees. On the back of the fans, colorful rhyming verses describe animal signs, and invite ``every family and household to report forecasts.''