The curled-up bodies of a stillborn fetus and a 5-week-old infant buried in a dune beside an Alaskan river are being hailed as the oldest known remains of Native Americans who crossed from Asia during the last ice age.

The two, who might have been related by blood or band membership, had been buried side by side in a circular pit, along with carved hunting spears, several feet below a subsequent cremation of another child, said a study published online in the journal Proceedings of the National Academy of Sciences.

Carbon dating suggests all three died about 11,500 years ago, during summer occupation of the Upward Sun River site along the Tanana River in central Alaska, the study said. "This represents the oldest known human remains that have been found in the northern North America β€” the arctic and sub-arctic," said archaeologist Ben Potter of the University of Alaska, Fairbanks, lead investigator of the study.

The remains also represent the youngest-aged specimens and the only fetus to be unearthed in the region. Researchers say the two burials, along with a later one excavated from the same pit, offer intriguing clues to burial practices related to belief systems of the early ancestors of northern American Indians.

The spear fore-shafts, shaped from antelope horns and decorated with abstract etchings, were in close contact with stone points that were beveled on both sides. They bear striking resemblances to implements found in northeast Asia, lending support to theories that the first occupants of North America crossed a land bridge across the Bering Sea when sea levels fell during the last ice age.

los angeles times