A massive tooth believed to be at least 10,000 years old has been uncovered in a California creek, offering scientists an unusually well-preserved glimpse of an extinct Ice Age mammal that once moved through the West Coast.
The discovery started quietly over the summer, when a researcher noticed what first appeared to be a strangely shaped rock resting in a creek bed in San Mateo County.
On Wednesday, paleontologists confirmed the object was not a rock at all, but an intact adult Pacific mastodon molar, according to a news release.
Pacific mastodons, enormous shaggy relatives of modern elephants, once ranged widely across the West, including California, Oregon, the northern Rocky Mountains and parts of Mexico, for millions of years.
The animals lived during the Pleistocene epoch, a period that began around 2.5 million years ago and came to a close when mastodons disappeared roughly 11,700 years ago.
‘The tooth itself is in immaculate condition. It’s the most complete mastodon molar from our area, and the most spectacular mastodon molar that I’ve ever seen,’ said Wayne Thompson, a paleontologist and owner of the firm Pacific Paleontology.
‘I had chills and shivers up and down my spine,’ Thompson added. ‘It’s another puzzle in the Ice Age saga that we can put into place.’
The rare mastodon tooth find was announced by the Midpeninsula Regional Open Space District, known as Midpen, which has protected more than 70,000 acres of open space across the Bay Area.
A giant tooth dating back at least 10,000 years that was found in a California creek was revealed to be an intact, adult Pacific mastodon molar
The enormous, hairy relatives of today’s elephants once dominated parts of the West, roaming across California, Oregon, the northern Rocky Mountains and parts of Mexico for millions of years
The remarkable find came after Brigid Lynch (pictured), a geomorphologist, stumbled across what she believed was a bizarrely shaped rock while researching the threatened California red legged frog
It came after Brigid Lynch, a geomorphologist with Balance Hydrologics, was conducting field surveys in June for a Midpen project aimed at supporting the threatened California red legged frog.
She initially believed the object was a bizarrely shaped rock, with photos showing what appeared to be a bear claw poking out of the water. Paleontologists later revealed the groundbreaking truth.
‘As a geologist, I’ve gone out and seen stuff in the field, but definitely nothing as exciting as this,’ Lynch said in a statement, according to Midpen’s news release.
Scientists said the Ice Age relic could shed new light on the Pacific mastodon, a distinct species that was only officially recognized in 2019.
Narrower teeth, thicker leg bones and differences in its tusks set the Pacific mastodon apart from its American counterpart, experts explained. But much about the ancient creature remains a mystery.
‘Unlike mammoths, which were also present in the region and fed on grasses, mastodons were considered browsers, using their massive trunks to strip leaves, soft shoots or fruits of high-growing, generally woody plants,’ the news release said.
They are believed to have lived alongside other extinct giants in ancient California, including bison sized Jefferson’s ground sloths, Columbian mammoths and western camels.
In July, just weeks after the remarkable discovery, the tooth was donated to Stanford University’s Doerr School of Sustainability, where scientists can continue studying the fossilized treasure.
In July, just weeks after the remarkable discovery, the tooth was donated to Stanford University’s Doerr School of Sustainability
Pacific mastodons roamed the West during the Pleistocene epoch, which began about 2.5 million years ago and ended roughly 11,700 years ago with their extinction
Researchers plan to carbon date the tooth to determine its exact age, then create a 3D scan and printed replica that Midpen can use to educate the public about the prehistoric find.
‘Fossils are our only opportunity to see into past biodiversity,’ Christine Garcia, curator and manager of the Geoscience Specimen Collection at Stanford, said in the news release.
‘We can study fossils to better understand Earth’s past, past wildlife and the ecosystem they were a part of, and to help us make better predictions and better decisions about how to help our ecosystems and biodiversity thrive into the future.’
However, the latest find is not the first Pacific mastodon tooth discovered in the region. In 2023, a woman found a separate fossilized tooth while walking along Rio Del Mar State Beach near Santa Cruz, according to The Los Angeles Times.
She initially thought the foot long object she spotted during the Memorial Day holiday was simply a piece of driftwood. Unsure what she had found, she posted a photo on Facebook asking if anyone knew what it was.
‘People from Aptos find all kinds of stuff washed up on that beach, like horse teeth or fossilized sand dollars,’ Jennifer Schuh said, according to the outlet.
‘And I was like, “Well, shoot, I’m going to post this crazy thing because I have no idea what it is,”‘ she added.
Someone in the comments tagged Wayne Thompson, who also serves as a paleontology adviser for the Santa Cruz Museum of Natural History.
Wayne Thompson (pictured left), paleontologist and owner of the firm Pacific Paleontology, said: ‘I had chills and shivers up and down my spine. It’s another puzzle in the Ice Age saga that we can put into place’
Pacific mastodons are believed to have lived alongside other extinct giants in ancient California, including bison sized Jefferson’s ground sloths, Columbian mammoths and western camels
Researchers plan to carbon date the tooth to determine its exact age, then create a 3D scan and printed replica that can be used to educate the public about the prehistoric find
Thompson responded to Schuh’s post, writing: ‘This is an extremely important find. Give me a call when you get the chance.’
He eventually confirmed the mystery object was a Pacific mastodon molar, which was later donated to the Santa Cruz Museum’s artifact collection.
At the time, he revealed that the tooth was one of just three known Pacific mastodon specimens ever found in the area.
‘When this tooth was fossilized, sea levels were 300 feet lower than they are today. Elephants and mammoths could walk out to the Channel Islands,’ Thompson said, according to the LA Times.
‘It’s another piece of evidence that we have for climate change,’ he added.
