Ancestors who came in from the cold.

The Russian Arctic's bitter cold and flat expanses present a formidable challenge to survival. Yet either Homo sapiens or Neandertals were living there by around 36,000 years ago, according to a report in the Sept. 6 NATURE.

Until now, excavations had revealed a human presence in the far reaches of northern Asia only as early as 14,000 to 12,000 years ago (SN: 7/7/01, p. 7).

A Russian and Norwegian team, led by Pavel Pavlov of the Russian Academy of Sciences in Syktyvkar, unearthed the remains of an ancient human occupation in riverbed deposits at a Russian Arctic site. Finds include several stone tools, the bones of mammoths and other animals that had apparently been butchered, and a 4-foot-long mammoth tusk bearing signs of being chopped with a sharpened stone. It's unclear why someone made these grooves on the tusk.

Radiocarbon analyses of the marked tusk and three animal bones provided an age estimate for the occupation site.

The new find "implies that either the Neandertals expanded much further north than previously thought or that modern humans were present in the Arctic only a few thousand years after their first appearance in Europe," the scientists say.