Three Russian scientists have turned up evidence that a race of "dwarf" mammoths, cut off from the rest of the world on a remote Arctic island, survived the extinction of all other mammoths by up to 6,000 years, living on into comparatively recent times.

The scientists' conclusion came after the discovery of 29 complete but very small mammoth teeth, as well as many tooth and bone fragments, on Wrangel Island, a Russian possession in the Arctic. By analysis of proportions of carbon isotopes in the teeth, the scientists determined that the teeth were 7,000 to 4,000 years old, which is far younger than any previously known mammoth fossils.

Paleontologists previously believed that all mammoths were extinct by 9,500 years ago and that mammoths had disappeared from most of their ranges in Europe, North America and Asia by 12,000 years ago.

The mammoth teeth from Wrangel Island are up to 25 percent smaller than those of ordinary woolly mammoths, whose known fossils are all much older. The teeth were those of adult mammoths, which can be easily distinguished from those of juveniles by their cellular structure.