This paper describes a new-discovered upper right second molar of Palaeoloxodon naumanni from Yubetsu, Hokkaido, that was found in August 1998, and suggests that alternating migration of two kinds of proboscidean, Mammuthus primigenius and Palaeoloxodon naumanni, took place there in relation to climate change. ¹⁴C dating of the root of the molar gives an age of 30, 480±220yrs BP (measured ¹⁴C age). Although the fossil molar was found loose, geological investigations suggest strongly that it derives from a peaty silt bed distributed around ravine in which the fossil was found. This bed includes the Ds-Oh (Daisetsu-Ohachidaira) volcanic ash of 30ka.
Judging from the ages and vegetations of the formations from which P. naumanni or M. primigenius remains have been found in Hokkaido, vegetation change controlled by global climate change seems to have affected the migration of the two kinds of proboscidean into Hokkaido. The discovery of P. naumanni remains of 30ka in Hokkaido suggests the possibility of a northward re-migration of P. naumanni from Honshu during the MIS 3.