New insights into Eastern Beringian mortuary behavior: A terminal Pleistocene double infant burial at Upward Sun River

Here we report on the discovery of two infant burials dating to ∼11,500 calibrated years (cal) B.P. at the Upward Sun River site in central Alaska. The infants were interred in a pit feature with associated organic and lithic grave goods, including the earliest known North American hafted bifaces with decorated antler foreshafts. Skeletal and dental analyses indicate that Individual 1 died shortly after birth and Individual 2 was a late-term fetus, making these the youngest-aged late Pleistocene individuals known for the Americas and the only known prenate, offering, to our knowledge, the first opportunity to explore mortuary treatment of the youngest members of a terminal Pleistocene North American population. This burial was situated ∼40 cm directly below a cremated 3-y-old child previously discovered in association with a central hearth of a residential feature. The burial and cremation are contemporaneous, and differences in body orientation, treatment, and associated grave goods within a single feature and evidence for residential occupation between burial episodes indicate novel mortuary behaviors. The human remains, grave goods, and associated fauna provide rare direct data on organic technology, economy, seasonality of residential occupations, and infant/child mortality of terminal Pleistocene Beringians. Significance Two interred infants with associated grave goods and a third cremated child represent the earliest known human remains from the North American subarctic, and they provide evidence for novel mortuary behaviors at the end of the last Ice Age. Two bifacial points with decorated foreshafts represent hafted projectiles, confirming earlier conclusions about Paleoindian weapon system form and function. Excellent faunal and other contextual data indicate broad-spectrum foraging behaviors.