JOHANNESBURG, South Africa -- An American researcher believes that he has solved the mystery of how one of the most important human ancestors died nearly 2 million years ago: An eagle killed the 3 ¹/₂-year old ape-man known as the Taung child.

The discovery suggests that small human ancestors known as hominids had to survive being hunted not only by large predators on the ground but also by fearsome birds of prey that swooped from the sky, said Lee Berger, a senior paleoanthropologist at Johannesburg's University of the Witwatersrand.

The discovery of the partial skull of a juvenile ape-man in South Africa's North West Province in 1924 revealed a human ancestor species called Australopithecus africanus, which was proposed to be the "missing link" between apes and humans. It also gave evidence that early humans evolved in Africa, rather than Europe and Asia, as most scientists believed at the time.

The child's death has been blamed on a leopard or saber-toothed cat, which are known to have preyed on hominids. But 10 years ago, Dr. Berger and fellow researcher Ron Clarke submitted the theory that the hunter was a predatory bird, similar to today's African crowned eagle.

The researchers argued that the skulls and bones of monkeys and other animal fossils found at the Taung site, about 300 miles southwest of Johannesburg, showed evidence of damage by eagles. Other researchers agreed that eagles were likely preying on small animals at the site, but contended that ape-men were too large, sophisticated and organized to be taken by a bird.

Five months ago, researchers from Ohio State University submitted what Dr. Berger called the most comprehensive study to date of eagle damage on bones. He was among those asked to review the paper for the American Journal of Physical Anthropology.

The study by Scott McGraw, Catherine Cooke and Suzanne Schultz of primate remains from modern crowned eagle nests in Ivory Coast's Tai forest showed that raptors routinely hunt primates much larger than themselves by swooping down and piercing their skulls with their back talons. There is even a documented case of an eagle killing a child, Dr. Berger said.

The Ohio State paper identified key features that distinguished damage caused by eagles from that of other predators. They include the flaps of depressed bone on top of the skull caused by the birds' talon and keyhole-shaped cuts on the side made by their beaks, noted by Drs. Berger and Clarke in their 1995 paper.

The study prompted Dr. Berger to re-examine the Taung skull, which showed damage consistent with the Ohio team's findings.