A community member brought in this mastodon skull to the Museum of Natural History when local paleontologist Wayne Thompson was 18-years-old and working the museum’s front desk. SANTA CRUZ — During the last ice age, known as the Pleistocene, Santa Cruz County was a wild place populated with ancient humans and larger-than-life creatures, or megafauna, such as mastodons and mammoths.
The forearm bone of a Jefferson’s ground sloth, the first of its kind found in Santa Cruz Couny, is on display at the Santa Cruz Museum of Natural History. “We tapped into our resources and connections and had it confirmed it to be this very rare specimen,” said Van Stolk. “We were just over the moon.”
“That data hasn’t yet come back to us from the testing facility,” said Thompson. “There are a number of ways to date fossils and the first one that we are trying relies on the presence of the biomolecule collagen, which is a protein. If there’s enough collagen in the bone, we can calculate its age up to about 50,000 years. If it’s older than that, we’ll have to use other methods using elements like uranium or thorium.
Jefferson’s ground sloths lived near creeks and rivers and under canopy forests and were about as big as an ox and generally weighed more than a ton. When the massive, slow-moving herbivores weren’t camping out in caves, they would be roaming around, sometimes standing on their hind legs, using their three long claws to strip the leaves from branches of trees such as spruce and alderwood.
“It’s because of all the ice,” said Thompson. “Ice age Santa Cruz would have been bigger and we have found mammoth fossils in the bay.”