According to revelations in Fossils in the Asphalt, a "Human Footprint" episode on the PBS/KQED program Unearthing LA's Ancient Past, there is new research that prehistoric extinctions of giant creatures, such as mammoths and short-faced bears, resulted from massive wildfires across California.
Charcoal deposits dated to 13,000 years ago found in the La Brea Tarpits indicate that wildfire was likely one of the main reasons that the megafauna was wiped out. Excavations of fossilized bones and body parts from herbivores and predators that date to the same time period bolstered the evidence that they died when the landscape was on fire.
Until now, scientists believed that over-hunting by early peoples, and climate change, were the main reasons that huge sloths, oversized bison and saber-toothed cats disappeared from California's Serengeti during the end of the last Ice Age. The new findings tie the mega wildfires to both burning by Paleo-Indian people and lightning. Centuries-long droughts also contributed to the inferno.
The disappearance of the megafauna took place over the course of about 300 years, at the end of the Pleistocene epoch, said the researchers. The big animals were replaced by more familiar wildlife, such as coyotes. Fire adapted plants like manzanita and shrubby chaparral emerged afterwards to replace woodlands, and now dominate many areas of the state.
The research was first published in Science in 2023, but was definitely new to me.
"We used samples from over 170 animals of seven megafauna species - saber-toothed cats, dire wolves, lions, camels, bison, horses and sloths," said Emily Lindsey, a co-author of the research paper. "Around 13,000 years ago, our record of all of those animals stops, and it's just coyote, coyote, coyote, coyote."
Since the focus was Southern California, I wondered if Sonoma Valley experienced the same wildfires and what our land looked like during the same time period. While I couldn't find any studies on paleoclimate specific to Sonoma Valley, a google AI search suggested that Northern California and probably our area did experience wildfires when immense mammals walked the Valley of the Moon. Google information reports that while the frequency and intensity of prehistoric fires likely differed between Northern and Southern California due to varying climate patterns and vegetation, both regions were undeniably shaped by fire long before modern humans arrived.
Certainly ancient megafauna lived here as part of the California Serengeti. In fact, Sonoma Valley's own resident archaeologist, Breck Parkman, suspects that Columbian mammoths may have stomped down the original pathway that now exists as Highway 12. He also thinks that some of the vernal pools here and across the state may have originated as wallowing depressions from the supersized elephant-like bulldozers. He made these comments during a presentation to the Sonoma Land Trust in December 2020.
In a 2024 interview, Parkman said that during the late Pleistocene epoch, Sonoma Valley was likely to include almost all of the California Serengeti's extinct species, such as the Columbian mammoth, American mastodon, ancient bison, saber-toothed cat, dire wolf, American lion, giant ground sloth, western camel, western horse, llama, shrub ox, giant beaver and short-faced bear.
Parkman is well known and respected in Sonoma Valley and internationally for his research, discoveries, and expertise. One of his prominent local findings was a fossilized Monterey pine in Sonoma Creek, up in Sugarloaf State Park, after the storms of 2005/06 eroded the streambanks.
Out on the coast, he recorded the polished stone high up on the Mammoth Rocks on the Kortum Trail that show where the mammoths and supersized bison probably scratched their bodies.