A well-preserved tooth from a Pacific mastodon, an ancient relative of the elephant that once roamed North America, was discovered in a creek in the San Francisco Bay Area. The fossil was found by Brigid Lynch, a geomorphologist at Balance Hydrologics, while she was working on a habitat restoration project for the threatened California red-legged frog in a preserve managed by the Midpeninsula Regional Open Space District in San Mateo County. The tooth is about 9 inches long and is in excellent condition, with both the crown and root preserved, including a visible root canal. The fossil has been donated to Stanford University's Doerr School of Sustainability, where it will be studied and preserved. Chrissy Garcia, curator and manager of the school's specimen collections, called the specimen "exciting" and highlighted its exceptional quality. The Midpeninsula Regional Open Space District, which protects over 70,000 acres of land in the Santa Cruz Mountains, announced the discovery this week, emphasizing the significance of the find in understanding the region’s prehistoric past. Ron Tykoski, vice president of science and curator of vertebrate paleontology at the Perot Museum of Nature and Science in Dallas, noted that mastodon fossils are not uncommon in certain areas, depending on local geology and history. He explained that these fossils often appear in regions where the right conditions have preserved them over thousands of years. The Midpeninsula Regional Open Space District plans to create a 3D copy of the fossil for public outreach and educational purposes, allowing more people to learn about prehistoric life. Ryan McCauley, a spokesperson for the district, stressed the importance of preserving open spaces and habitats, saying that the discovery underscores the value of such conservation efforts. By maintaining natural areas, the district not only supports endangered species like the California red-legged frog but also helps uncover and protect important historical and scientific resources. The tooth’s discovery serves as a reminder of the rich natural and prehistoric history hidden within the region’s landscapes.