Giant Ground Sloth at County Museum

Visitors to the San Bernardino County Museum are now greeted by the skeleton of a giant ground sloth in the entrance foyer. The full mount skeleton, shown in an environmental setting, is an exact replica of the fossil sloth recovered by the Museum’s Geology Division from Devil Peak Cave near the Nevada border. The exhibit was unveiled by Dennis Hansberger, San Bernardino County 3^rd District Supervisor.

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The specimen is a Shasta ground sloth, Nothrotheriops shastensis. The species was the smallest of the North American sloths, standing just over three feet at the shoulder, eight feet in length, and weighing about 1,000 pounds. Ground sloths first arrived in North America about 9 million years ago and became extinct at the end of the Ice Age. The Shasta ground sloth roamed North America between 1.8 million and 11,000 years ago: the Devil Peak sloth is about 20,000 years old.

Fossilized dung of the Shasta ground sloth indicates that it ate plants, browsing on Joshua trees, yuccas, squaw tea, salt brush, mesquite, and cactus. Its long front claws probably hooked branches as it ate. The claws would also have been a formidable defense against predators such as saber tooth cats.

The fossil sloth was excavated by Museum volunteers as part of a joint effort between the Bureau of Land Management, Las Vegas District, and the Museum. Although Devil Peak Cave was a comfortable shelter during the Pleistocene, 20,000 years of erosion left the entrance perched high on a cliff side in an inaccessible canyon. Volunteers had to hike, scramble, and construct a series of ladders to reach the cave entrance. The cave’s interior was filled with layers of sediment that preserved the sloth and associated fossil animals. Volunteers had to work lying on their stomachs to excavate the specimens.

Exact replicas of each fossil bone were made at the Museum and two complete skeletons were mounted: the second was presented to the Nevada State Museum. The original fossils are conserved in environmentally-controlled protective storage. The sloth exhibit was funded by the County of San Bernardino and the San Bernardino County Museum Association.