News Life Around 13,000 years ago, humans and fire changed LA’s ecosystem forever Mammals like ancient bison and dire wolves couldn't survive the fiery shift As human-ignited fires burned and transformed the landscape of La Brea around 13,000 years ago, ancient bison (Bison antiquus) fled the flames and become entrapped in asphalt seeps (illustrated). The bison, along with six other species of megafauna, soon disappeared from the Southern California region, a new study finds.