The mass extinction of ice-age Megafauna that occurred around 12,000 years ago was caused by the thousand year long cooling event called the Younger Dryas.
It was possibly caused by an impact event on the retreating Laurntide ice shield. The effects were very abrupt, in line with impact related event effects. This extinction event is often used by anti-hunting groups to fit their agenda, blaming it on Humanity.
The most notable species to survive the event was the American Bison, in a somewhat smaller form, that was able to recover and expand across the whole of American grassland ecosystems.
Don't fall for the "Humanity is the Rapist of the Earth" mythology.
Regards
Ken
