Hrdlička's Aleutian population-replacement hypothesis: A radiometric evaluation

In a 1945 monograph, Hrdlička argued that, at 1,000 BP, Paleo-Aleut people on Umnak Island were replaced by Neo-Aleut groups moving west along the island chain. His argument was based on cranial measurements of skeletal remains from Chaluka Midden and mummified remains from Kagamil and Ship Rock burial caves. By the 1980s, researchers had concluded that the transition demonstrated by Hrdlička, from a high oblong to a low-vaulted wide face, was merely one example of a global trend in cranial morphology and therefore population replacement had not occurred. Calibrated accelerator radiocarbon dates on purified bone collagen from 80 individuals indicate that Paleo-Aleuts were the oldest population in the Aleutians, with a time depth of ca. 4,000 years, that Paleo- and Neo-Aleuts were fully contemporary on Umnak Island after 1,000 BP, and that the former continued to bury their dead as inhumations long after the introduction of Neo-Aleut mummification practices. These results as well as features of the Aleut dietary, genetic, and material record suggest that the appearance of Neo-Aleut people represents an influx of closely related people characterized by greater social complexity and that social disparities that may have existed between Paleo- and Neo-Aleuts were largely subsumed in the social and demographic upheaval following Russian contact.