Ice age sloth skull found in Riverside County

The skull of an ice age giant ground sloth was recently uncovered at a construction site in Riverside County and could be headed for display at the San Bernardino County Museum.

The bones dating back 1.8 million years were discovered Nov. 18 on the site of a future Southern California Edison substation as earthmovers flattened the land in a hilly area west of Beaumont, said Rick Greenwood, director of Edison’s environment health and safety division.

Work in the area was immediately halted.

“It’s an extremely important specimen,” said Jennifer Reynolds, spokeswoman for the San Bernardino County museum. “Finding the skull of an ice age animal is just extremely exciting.”


This is the first time sloth fossils so old have been found west of the Rocky Mountains, Reynolds said. The sloth fossils found at the La Brea Tar Pits are about 1 million years younger, she said.

A contracted archaeologist monitoring the Edison construction site noticed patches of white around the discovery site, and work was stopped. The company’s construction license requires it to have expert monitors on-site.

The license also stipulates that any fossils found be turned over to the county museum, Greenwood said.

“It’s required in all of our work to take all of these things into consideration,” he said.

At the museum, the skull will be studied and could provide information about how the sloths lived, their habitats and their evolution, Reynolds said.

“Fossils are very, very rarely preserved; so many things can happen to the body of an animal when it dies,” she said. “And then when you add to that the passing of more than a million years, the chances of finding a skull are just very, very low.”

If the skull is later put on display at the museum, it will be placed in the Hall of Geological Wonders, set to open in the spring. The exhibits in the hall are focused on the geology and paleontology of Southern California.

“Sloths fit right into that,” Reynolds said.