File:Ranger Holding Mammoth Tooth (37125060224).jpg

Many are surprised that Great Sand Dunes National Park and Preserve contains numerous fossils, and are even more surprised that these fossils tell us important information about the park's geologic origins!

This real mammoth tooth held by Ranger Holly Scott reveals that the San Luis Valley was once much wetter than it is today. Columbian mammoths that once roamed this valley were even larger than woolly mammoths, and needed to eat over 700 pounds (317kg) of vegetation each day. That means this desert valley used to be covered with large lakes and rich plant life.

As the climate naturally changed, the vast lake system was reduced to the small wetlands present today. Mammoths disappeared, and the people that hunted them moved to wetter regions. The sheet of sand from the bottom of these lakes blew with the wind, funneling into a pocket of the Sangre de Cristo Mountains, and forming the Great Sand Dunes.

Scientists aren't yet certain how old the dunes are, but are very certain that they originated from these ancient lakes. The next time you visit the dunes, look to the west and imagine huge mammoths being hunted by early people around verdant lakes. Change has always been a part of human history, but change is not always negative. In this case, change resulted in these dunes that are enjoyed by hundreds of thousands of visitors every year!

Please remember that all fossils, artifacts, and natural objects belong to the American people as a whole, and are protected by federal law. Please leave them in place for scientists to study and learn more about the history of Great Sand Dunes.

Photo: NPS/Patrick Myers

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