Smilodons seem to have thrived within the last Ice Age, between 18,000 to 11,000 years ago but they generally do not show signs of survival past 11,000 years, with the exception of the Nashville remains.
As the Ice Age began it created land bridges into the American continent, providing a path from which the Smilodon could enter.
Their problems, as with the Great Wooly Mammoths, Mastodons, and the Land Sloths seem to have begun around 12,000 years ago as a much more Stealthy Predator arrived, who was better equipped in killing its prey.
Humans followed the same land bridges as the other creatures had used centuries earlier and as they arrived they hunted the same prey as the Smilodon. They most surely found easy hunting stalking a prey that had never been exposed to them and possessed no fear of a much smaller foe. Man possessed spears and other hunting tools, which proved to be the equalizers.
Even if man did not hunt the Smilodon, he eliminated its prey, and thus the Mammoths, Mastedons, Ground Sloths and the Smilodon, show extinction at the same time.
I guess it's not by chance that cave drawings in the world depict no Conservationism, Reserve or Mercy.


