Ben Potter and colleague Joshua Reuther excavate the burial of two infants at Upward Sun River in Alaska.

Ben Potter and colleague Joshua Reuther excavate the burial of two infants at Upward Sun River in Alaska.

UAF photo courtesy of Ben Potter

Infant burials could help solve the mystery of who settled the New World

Five years ago, Ben Potter made a dramatic discovery: the partially burned remains of a cremated 3-year-old child, left to rest in a hearth at Upward Sun River, one of the oldest settlements in Alaska. But the University of Alaska, Fairbanks, archaeologist never expected what waited underneath the hearth. More recent excavations have yielded two well-preserved burials, of an infant who likely lived for about 12 weeks and a fetus who died shortly before birth. The discovery provides a window into daily life and burial practices at the 11,500-year-old site, and an unprecedented opportunity to analyze the DNA of some of the Americas’ earliest inhabitants.

Upward Sun River, near the Tanama River in central Alaska, is one of the most important archaeological sites discovered in the Beringia region of the Arctic in the last 25 years, says John Hoffecker, an archaeologist at the University of Colorado, Boulder, who wasn’t involved with the research. Most Paleoindian sites found in Alaska are short-term hunting camps, which fit with a long-standing vision of the region’s earliest settlers as nomadic big-game hunters who crossed the Bering land bridge about 14,000 years ago in pursuit of prey like woolly mammoths and elk. Upward Sun River, in contrast, shows signs of longer term occupation, including the remains of the earliest known residential structures in Alaska. The hearth over the two buried bodies contains traces of salmon and ground squirrels, indicating that the occupants did not solely depend on bringing down large mammals, Potter and colleagues report online today in the Proceedings of the National Academy of Sciences. This evidence of a wider variety of food sources is “causing us to reevaluate what some of the subsistence [behaviors] would have been like in these early sites,” says Greg Hare, an archaeologist with the Government of Yukon in Whitehorse, Canada.

The burials, too, make the site unique in Alaska. The two skeletons were carefully arranged in the same pit and are almost entirely complete, a level of preservation that “boggles my mind,” says G. Richard Scott, a physical anthropologist at the University of Nevada, Reno. They were interred with antler rods and stone projectile points, which Potter believes were once lashed together to form a spearlike weapon called a hafted biface. “You can even see the whittling marks left on the edges of [the antlers],” which could help reveal how the weapons were made, Potter says. The grave goods were coated in red ochre—a common practice in Paleolithic burials around the world—and radiocarbon dating of one of the antlers shows that they are the earliest known example of the hafted biface technology in North America.

Because the burial and the later cremation are the only two examples of mortuary practices in Paleolithic Alaska, it’s all but impossible to be sure why two bodies were buried and one was burned, Potter says. The salmon found throughout the hearth is a food source available only in the summer, which indicates that the burials and the cremation likely occurred during the same season or in two subsequent years. One speculation from Potter’s team is that the buried children were twins. According to this hypothesis, one fetus died in the womb shortly before birth, which is known to boost the risk of premature birth, developmental problems, and death of the surviving twin. The other infant survived birth but died a few weeks or months later, and the bodies were interred together. The cremated child likely died later in the season or the following year and was burned in the hearth before the community abandoned the site.

The only way to settle the question of how the children are related to each other—as well as to other Paleoindian groups and living people—is to analyze their DNA, Potter says. “The most exciting thing is going to be the genetics,” Hoffecker says. “There’s still a question here as to exactly who these people are at Upward Sun River.”

Anthropologists debate how many groups of people were present in Beringia at different times and where each of them may have come from. Potter notes that burials of children within residential structures have also been documented in Ushki, a site in eastern Siberia, so the practice could link communities on either side of the Bering Strait. Hoffecker points out that the biface stone points are very similar to those found at the Anzick site in Montana. “If it’s possible to successfully analyze the DNA [from the burials], it could open the door to all kinds of new insights into the colonization of the New World,” Hare agrees. Potter says ancient DNA analysis is already under way, with cooperation from the tribes living in the Upward Sun River area today.