Recent archeological investigations in Hokkaido have shown that while the prehistoric culture in the southwestern part of the island was closely related with that in the northern part of Honshu throughout the Jomon and epi-Jomon Periods, those in the central and northeastern parts of the island comprised various elements quite alien from Japanese Jomon culture. In succeeding Satsumon Period and historic times, the cultures in Hokkaido have been relatively homogeneous, with the exception of the Okhotsk Coast area which was temporarily occupied by the Okhotsk Culture from the end of the epi-Jomon through the Satsumon Periods.
Human skeletal remains excavated so far in Hokkaido were reviewed separately for the three prehistoric cultural areas: the southwestern, the northeastern and the Okhotsk areas. Those from the Jomon sites in the Southwest were found to be closely related in morphological features as well as in metric characteristics with the skeletal remains of the Jomon population in Honshu. Those from later periods in the Southwest, however, showed gradual change to a form more closely resembling the modern southwestern Ainu. On the other hand, the skeletal remains from the Northeast were found to have been very close morphologically to the modern northeastern Ainu since the beginning of the Jomon Period. Skeletal remains derived from the Okhotsk culture area, as represented by the Moyoro shell-heap materials, were found to resemble northern neighbours such as the Sakhalin Ainu, the Gilyak and the Ul'chi.
It was tentatively concluded from the above findings and some distance analysis that the form of the Hokkaido Ainu proper was best represented by the modern Ainu in the northeastern part of the island exclusive of the Okhotsk Coast area.
Craniological materials collected mainly from the northeastern part of the island by KOGANEI (1893) were analyzed by Mahalanobis' distance method for the purpose of seeking morphological proximity among fifty populations in northern Eurasia, Far East, Oceania, and North America. Among other things, unexpected resemblance was detected between the Ainu and the prehistoric human remains from Alati-Sayan highland in Siberia (ALEKSEEV, 1961). Further developments in archeology and paleoanthropology in Siberia and Hokkaido are needed before any conclusion can be drawn from this interesting finding.