Unlike what you might have learned in history class, the first Americans didn’t sail to the New World in 1492. They actually walked across a tiny stretch of land about 25,000 years earlier. Newly found remains of two ancient babies have put a new spin on the story of the first Americans, as they suggest early migrants settled in Northern Alaska for as long as 10,000 years before eventually moving down to warmer climates, according to a new study.

It’s well known life began in Africa, but at some point in history, small groups of our ancient ancestors decided to leave the warmth of their motherland to explore the great unknown. It’s this innate desire to explore that led humans to populate every corner of the world. Breaking off in the name of exploration meant groups would often become isolated for many thousands of years. In this isolation, certain traits and genetic mutations were able to flourish and thrive, and today, scientists can look at these genetic variations in our DNA to gain a better understanding of early human civilizations.

The genetic diversity seen in modern day Native American populations doesn’t match that of any populations in Asia and Russia. This oddity suggests the first Eurasian migrants to North America experienced a long period of isolation before their southern migration. "You don't see any of these lineages that are distinctly Native American in Asia, even Siberia," senior author Dennis O’Rourke said in a recent statement. "So there had to be a period of isolation for these distinctive Native American lineages to have evolved away from their Asian ancestors. We believe that was in Beringia."

This theory, known as the Beringian standstill model, has had little concrete evidence to back its validity up until recently. But when researchers from the University of Utah discovered the remains of the two 11,500-year-old infant remains buried in an Alaskan camp site, it gave rise to the possibility the Beringian standstill model may be true.

The study found these infants are the earliest human remains to ever be found in North America. What’s more, the remains were found at the northernmost point of only eight burial sites in North America that contain remains older than 8,000 years old. Genetic testing revealed the infant DNA didn’t match the DNA of northern Native Americans, but instead, it matched the DNA of native tribes spanning the southernmost parts of North and South America.

"We see diversity that is not present in modern Native American populations of the north and we see it at a fairly early date," O'Rourke said. "This is evidence there was substantial genetic variation in the Beringian population before any of them moved south."

At the end of the last ice age — about 25,000 years ago — the sea levels receded so low that humans were able to walk from Siberia to Alaska along what is currently known as the Bering Strait. According to the Beringia standstill theory, giant glaciers prevented these first Americans from traveling further south, forcing them to settle in an area of Northern Alaska known as Beringia until the glaciers receded about 15,000 years ago. Today, most of Beringia is completely under water, seriously limiting archaeologists' ability to search for more ancient remains and artifacts.

Ted Goebel, an archaeologist at Texas A&M University, told The Salt Lake Tribune that these infant remains prove "without question" that the first Americans did indeed walk across the Bering Strait to Alaska. The study strongly suggests these first Americans settled in Alaska for thousands of years before pressing further south, but more importantly, the remains also "give us a snapshot of that earlier time," and help us better understand the story of mankind.

Source: O’Rourke DH, Tackney JC, Potter BA, et al. Two contemporaneous mitogenomes from terminal Pleistocene burials in eastern Beringia. PNAS. 2015.