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Shasta Ground Sloth

Terrestrial Fossil
Scientific Name: Nothrotheriops shastensis

Unlike modern tree sloths, extinct ground sloths grew to enormous sizes. Some species of ground sloth reached the size of elephants. The Shasta ground sloth, found in the Grand Canyon, was smaller than this, about the size of a bear. During the last Ice Age, the Grand Canyon was cooler and wetter than it is today, allowing vegetation to flourish. This would have provided plenty of food for such a large herbivore. This particular skull was found in Rampart Cave, where the dry, stable conditions are ideal for preservation. In addition to bones, this cave also preserved pieces of sloth fur and large amounts of sloth manure that still emits a strong odor despite being 11,000 years old. Studies of preserved sloth dung indicate that even after the climate became drier, the vegetation that took over would have been suitable for them to eat. This means the Shasta ground sloth was likely driven extinct by human hunting rather than climate change.

3D Shasta Ground Sloth—Nothrotheriops shastensis
Grand Canyon National Park, Arizona

A 3D model. This model shows a fossil skull. The model can be rotated and tilted using a computer interface.

Species - Nothrotheriops shastensis

Pleistocene giant ground sloth recovered from Rampart Cave. Collected in the 1930s during excavation work within the cave. In addition to bones, this cave also preserved pieces of sloth fur and large amounts of sloth manure.

This fossil skull is in the collections at Grand Canyon National Park, Arizona. Learn about paleontology in the National Park Service: https://www.nps.gov/subjects/fossils/index.htm

Learn more about Grand Canyon National Park’s Centennial: https://www.nps.gov/grca/getinvolved/centennial.htm

Part of a series of articles titled Grand Canyon Collections—Paleontology.

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Next: Crinoid Fossil

Grand Canyon National Park

Last updated: May 3, 2021