|A reconstruction of Thylacosmilus by the talented young artist Sam Lippincott. Interestingly, the super-sized canines of Thylacosmilus grew continually throughout its life, unlike those of Smilodon or Xenosmilus (see below), two of the actual saber-toothed cats. Photo Credit: Sam Lippincott|
Miocene and the Pliocene Epochs, from 10-2 MYA. Up until 2 MYA, South America had been its own, separate land mass, not connected to any other continents since some time during the Cretaceous. 2 MYA, however, something extraordinary happened: the Isthmus of Panama was formed, connecting the two continents. With this connection, came something scientists have dubbed the "Great American Interchange." Animals from both continents could move, and spread out into the other continents. For some creatures, like the saber-toothed cats, this was a good thing; they moved down into South America from North America and dominated the landscape. For other predators, like the terror-bird Titanis(again, a topic for another time), it was good, for a while; after moving into the southern part of North America, however, Titanis was outcompeted by other predators. For Thylacosmilus, it was down-right disastrous. Shortly after the Great American Interchange, fossil evidence of Thylacosmilus entirely disappears, similar to the competition between the dingo and the thylacine that drove the thylacine to extinction on mainland Australia.
|The skull of Thylacosmilus on display at the American Museum of Natural History in New York. Got to see this sucker in person in August 2014, when I visited with my good buddy Zach Evens!|