Researchers discovered the skeletons of two Ice Age infants that were buried about 11,000 years ago in central Alaska.

The finding marks the youngest human remains ever found in the North American Arctic, the National Science Foundation reported. The researchers found teeth, bones, and artifacts, suggesting a ritualistic burial. The findings could provide insight into how these early societies were structured and how they treated death.

"Taken collectively, these burials and cremation provide the first evidence for complex behaviors related to death among the early inhabitants of North America," said study leader Ben A. Potter of the University of Alaska Fairbanks .

One of the ancient skeletons was discovered about 15 inches below the other, which was uncovered back in 2010; the infants were cremated and found in the remains of a hearth. The radiocarbon dates of both set of bones were found to be identical to on another.

The researchers also found shaped stone heads in what are believed to be the earliest examples of "hafted bifaces, or projectile points found in North America.

"The presence of hafted points," the paper noted, the NSF reported, "may reflect the importance of hunting implements in the burial ceremony and with the population as whole."

The team observed salmon-like fish and ground squirrels in the pit, suggesting the area was occupied by hunter-gatherers between the months of June and August. The burial of the two infants within the feature suggest a longer-term occupation at the site.

The researchers are waiting for results from DNA tests of the remains, such as whether or not the children were twins (one died shortly after birth and the other was a late-term fetus). If the ancient infants were not twins it indicates there was a stressor at the time such as lack of resources such as food.

"The deaths occurred during the summer, a time period when regional resource abundance and diversity was high and nutritional stress should be low, suggesting higher levels of mortality than may be expected given our current understanding [of survival strategies," the authors wrote.

The findings were published in a recent edition of the Proceedings of the National Academy of Sciences.