How long have people inhabited the Americas? That is a very debated question that pulls in many different disciplines of science. Until recently the textbook answer was that it was around 13,000 years ago as mankind settled on the Bering Landbridge and then migrated down into the Americas as the ice retreated and the corridor was cleared.

But more and more the orthodox view is being challenged and new discoveries of human footprints in White Sands National Park in New Mexico are forcing the textbooks to be rewritten. Today one of the oldest permanent human sites being excavated are truly ancient sites of Karahan Tepe and Gobekli Tepe in Turkey.

White Sands National Park & Historic Climate

White Sand National Park is located in the Tularosa Basin and is completely surrounded by the White Sands Missile Range. It includes white sand dunes that are made up of gypsum crystal - the largest such dune field in the world. The depth of these dunes is around 30 feet or 9.1 meters and as tall as 60 feet or 18 meters.

  • Preserves: The Gypsum Dunefields

But during the ice age, this area was completely different. The Tularosa Basin has large lakes 12,000 years ago together with grasslands, streams, and Ice Age mammals.

  • Lake Otero: A Prehistoric Lake 1,600 Square Mile Lake That Dried Up 10,000 Years Ago

But as the climate warmed and the Ice Age receded rain and snowmelt dissolved the gypsum from the mountains in the area and carried it into to basin.

As time wore on the lakes evaporated leaving behind selenite crystals. These were then broken up by the strong winds and carried eastward. The gypsum is still continued being produced today.

There is more than just human footprints in this park. Once one government trapper spotted footprints from Bigfoot. These impressive footprints measure 22 inches long and 8 inches wide.

  • Bigfoot: Bigfoot's Big Foot Was The Big Foot Of A Big Footed Giant Ground Sloth

It was later on found to be the "big foot" of a giant ground sloth that once roams these parts of the continent.

Learn more about visiting the National Park on NPS's website as well as about the fossilized footprints.

The Last Glacial Maximum

  • Last Glacial Maximum: Spanned From 20,000 to 26,500 Years Ago

During the Last Glacial Maximum, the sea levels were much lower with so much water lockup in the massive ice sheets. Temperatures were lower and glaciers were much larger. Two massive ice sheets called Laurentide and Cordilleran covered much of what is now Canada and formed a continuous icy wall from the Pacific to the Atlantic oceans.

  • Sea Levels: Over 400 Feet Lower
  • Beringia: The Land Bridge That Connected Siberia with Alaska

Today the remanents of Beringia are protected in the Bering Land Bridge National Preserve in Alaska.

Related: How The World Has Reconstructed Ötzi The Iceman's Life

The Footprints In White Sands

Travel to White Sands National Park and one can find what is currently the possible oldest record of humans in the Americas. These remarkable prehistoric tracks date from the time of the Last Glacial Maximum and have been calculated as being some 22,860 to 21,130 years old.

  • Age: 22,580 to 21,130 Years Old

The footprints that have been discovered here are not only rewriting history, they even look like they were left behind just moments ago.

Since the initial discoveries in the 1930s, thousands of tracks in the national park have been discovered. These include more now-extinct ice age animals like giant sloths and mammoths preserved in the gypsum-rich sand.

One excavation site has eight separate horizons of footprints with 61 human tracks that were made by up to 16 different people - mostly teens and children.

  • Children and Teenagers: Most Of The Tracks Were Left By Teenagers and Children

The Bombshell To Science

They were preserved in the mud near one of those ancient lakes at a time when the ice sheets still covered North America and walled off human passage into the continent. It had been thought it would not have been possible to have populated the continent at that time, and yet there they are.

Before this discovery, it was thought that people arrived not later than 13,000 years ago, but that has been challenged by sites like Chile's Monte Verde at 18,500 years old and Texas's Gault site up to 20,000 years old. But all of the sites have been less than convincing for many scientists and have triggered intense debate.

"A discovery like this is very close to finding the Holy Grail"

Ciprian Ardelean - Archaeologist

Related: Historic: Before Göbekli Tepe, There Was Denisova Cave

Grass Seeds And Dating

It was very difficult to date these human footprints. But in 2019, Scientists got a lucky break. They discovered ancient seeds in the human footprints. Some of the track layers were bookended above and below with layers of sediment that contained seeds according to National Geographic.

  • Ruppia Grass: The Type of Grass The Seeds Are From

While scientists couldn't date the footprints themselves, they could radiocarbon date the seeds which were shown to be between 21,000 and 23,000 years old.

Next: Interested In Early Human Civilization? Visit One Of These Two Historic Locations