The remains of two Ice Age infants, buried more than 11,000 years ago, were discovered in Alaska, new research describes, providing new insights into ancient burial practices.

Ben Potter, a researcher at the University of Alaska Fairbanks, led an archaeological team that led to the 2013 discovery near the Tanana River in central Alaska. This was just three years after the cremated remains of another 3-year-old child were found. But this latest find - located in a pit just 15 inches below the 2010 excavation - represent the youngest human remains ever found in northern North America.

Dental and skeletal remnants indicate that one infant survived birth by only a matter of weeks, whereas the other died in utero. The fact that this area contains a trio of deaths - all around 11,500 years ago - indicates that people who inhabited the area thousands of years ago were under some environmental stresses, such as food shortages.

Alongside the human remains were unique burial offerings, including shaped stone points and antler foreshafts decorated with abstract incised lines - some of the oldest examples of weapons used in North America.

"The presence of hafted points may reflect the importance of hunting implements in the burial ceremony and with the population as whole," notes the paper, published in the journal Proceedings of the National Academy of Sciences.

Such findings are surprising because researchers had previously believed that early human cultures lack social organization and mortuary practices, given that they had no written language. But the special circumstances this study describes suggests otherwise.

"Taken collectively, these burials and cremation reflect complex behaviors related to death among the early inhabitants of North America," Potter said in a statement.

The artifacts found can help scientists paint a better picture of the lifestyle of early human societies, as well as explain how they managed to survive climate changes at the end of the last great Ice Age. The fact that two separate burial events occurred within the same area could indicate that that particular foraging group stuck around longer than previously thought.