A University of California, Los Angeles (UCLA) and La Brea Tar Pits' study said one likely reason for megafauna, that roamed Southern California, to go extinct was human-set fires. The large mammals included saber-toothed cats and dire wolves. "Around 13,000 years ago, our record of all those animals stops and it's just coyote, coyote," the research's co-author said.