Pleistocene open woodland scene from the western portion of the Grand Canyon/Painting by artist Julius Csotonyi

Once upon a time, a very long time ago, cheetahs chased mountain goats deep within the Grand Canyon, and sloths were among the faunal community, and sharks, not humpback chub, swam there as well.

That surprising past of a landscape viewed today as arid, rugged, and unforgiving has come to light courtesy of the largest park-specific paleontological inventory in National Park Service history. Vince Santucci, the Park Service’s senior paleontologist, was inspired by Grand Canyon National Park’s centennial in 2019 to sift through more than 160 years of paleontological studies in the park’s landscape that began with the first fossils collected from  Diamond  Creek  during the Ives Expedition in 1858.

“The Grand Canyon paleontological inventory, and similar work in other parks, reward us all with new and more complete information about prehistoric life and the ancient world where they lived," Santucci said.

The multi-year effort to study Grand Canyon National Park’s fossil record, conducted by the National Park Service and the Utah Geological Association, concluded with the recent publication of Grand Canyon National Park Centennial Paleontological Resource Inventory: A Center of Fossil Discovery and Research. 

The publication documents more than 1.2 billion years of paleontological history in the park and uncovered a rich fossil record. The study inventoried flora and fauna throughout the millennia and found such impressive fossils and those of Shasta ground sloths, Harrington's mountain goats, ancient sharks and the now extinct American cheetah -- which lived in Grand Canyon's limestone caves during the most recent Ice Age.

Skull from an extinct species of Mountain Goat that roamed Grand Canyon/NPS

Through the pages of the inventory readers are introduced to the scientists and researchers, from John Strong Newberry and Lt. Joseph C. Ives in 1858 to present-day geologists and paleontologists working in the canyon,” wrote Earle Spamer in a section of the collection addressing the history of paleontological research in the park. “As  these  highlights  of  the  last  three  decades  show, paleontology,  the  science  of  the  long-dead,  is  very  much alive at Grand Canyon. It is important to realize that it was quite convenient that most of the early fossil collections  from  the  canyon  went  to  the  Smithsonian  Institution, but as the 20th century progressed more collections began to arrive in universities and independent museums. It has become all the more urgent for federal resource managers to keep up with the ever increasing, widely dispersed, collections that are made on federal lands.  The  means  are  at  hand—through  the  diligent  work of individuals, of course, but also through the use of such documentary records as digital databases.”

Santucci said understanding the Grand Canyon’s fossil record will continue to advance with new discoveries every field season.

The inventory’s objective was to identify the scope, significance, distribution and management issues associated with fossils in the park. The NPS compiled paleontological resource information for the public, park managers and staff to better understand the park’s non-renewable paleontological resources and help with future park planning and decision-making, which may relate to park fossils.

The park’s substantial stratigraphic record shows the canyon has been home to ancient sharks, Permian plants, proto-reptiles, and now-extinct mammals as the environment shifted from hospitable oceans to harsh deserts over hundreds of millions of years.

Thanks to the collective contributions of National Park Service staff, park partners and other paleontologists, this new paleontological inventory catalogues fossil specimens in the park's museum collection and will contribute to new educational and interpretive efforts on Grand Canyon paleontology.