If the antiquity of the spears stands up under further study, the finding could lead to a major revision of thinking about early human behavior and culture. Until now, there had been a scattering of evidence of systematic hunting by pre-modern humans as early as 200,000 years ago. Most experts thought that such big-game hunting did not begin until 40,000 years ago; before that, in their opinion, human ancestors were probably opportunistic scavengers of meat and foragers of plants.

But the three wooden spears appear definitely to have been designed for hunting big game, Dr. Thieme and other experts said. Each one, an average of six feet long and two inches in maximum diameter, was carved from the trunk of a spruce tree. A sharp tip was carved at the base of the trunk, where the wood is hardest.

The center of gravity, or balance point, of each spear is almost exactly one-third of the way from the point, which suggests that these were weapons designed to be thrown at a large animal. Since they are heavy and were made with care along the same aerodynamic lines as a modern javelin, experts said, it is unlikely the spears would have been thrown at the occasional squirrel. Instead, they said, these people were after bigger game and investing considerable thought and time into the hunt.

''Found in association with stone tools and the butchered remains of more than 10 horses,'' Dr. Thieme wrote in Nature, ''the spears strongly suggest that systematic hunting, involving foresight, planning and the use of appropriate technology, was part of the behavioral repertoire of pre-modern hominids.''

Dr. Robin Dennell, a professor of prehistory at Sheffield University in England, said the objects are ''unquestionably spears'' and, being so heavy, must have been used by large, powerfully built people.