At the end of the last Ice Age, Southern California was teeming with giant sloths, ancient bears, saber-toothed cats, mammoths, and more. But then all at once, these giant mammals went extinct, and for decades scientists weren’t sure why.
Now after studying bones from the La Brea Tar Pits and Lake Elsinore, researchers have released a groundbreaking new study showing the likely cause of that giant extinction was a spike in massive fires — sparked by the arrival of humans.