At the end, when I put the title, I opted for the most striking title, but my intention was to title this entry: "Cave Lion, Sabretooth and Isthmus of Panama" ... for being this last element would change the configuration of these super-predators who lived North and South America. Let me explain.
Now, to get into this exciting evolutionary battle, we must consider two things:
1 - Today, the largest cat is the Siberian Tiger ... to about 105 cm and 220 kg.
2 - South and North America were cut off, separated by an ocean, and different species living in each of the old continent.
When in one place and at the same time coincide two similar species with similar characteristics and common prey, one of the two species usually be favored over the other. The species "loser" or disappears or should look other prey in other ecological niches that are not exploited by the species "winner". This, over the years can promote morphological changes occur in the species "loser" and then, the two species are no longer rivals to specialize each in their prey and their characteristics.
Well, this I had to tell you that you may understand better what happened between these two species: American cave lion (Panthera leo atrox) and the saber-toothed tiger (Similodon).
In the Pleistocene, there were these two species. The cave lion was king. It was clever, powerful, with a strong bite and we could say it was the super-predator. It weighed about 360 kg - 400 kg and no other animals, such as wolves, bears or other feline, was able to intimidate it. In fact, in its name we can appreciate the sentiment that created to its discoverers, atrox means terrible.
Then we have the second best, it was the saber tooth tiger (Smilodon fatalis), not that it was small. It was quite large and robust enough, maybe a little less intelligent and less social life. It weighed about 280 kg, so we could say that weighed the same as a Siberian tiger overweight ... but that does not exist in nature.
The cave lion weighed fourth part the sabertooth. And with that weight, this old lion, keeping at bay potential sabertooth. It would be like the African lion and leopard. The saber-tooth (as leopard) had to settle for smaller prey with other predators steal them and take care that they are not stolen and ultimately ... was content to be in the shadow of the Great Cave Lion .... But this did not last long ... the Sabretooth had his opportunity and took it.
In the mid-Pleistocene and in a process that lasted hundreds of years, North America joined with the south, forming what we known today as the Isthmus of Panama. This event is one of the most important, geologically speaking, of which have occurred in the last 60 million years. Varied weather gave way to global and fauna from north to south, and vice versa ... is called the Great American Interchange.
The first cross was the Smilodon fatalis. Over time and thanks to the lack of predators (thought) evolved a new species called Smilodon populator a kind to settle at the top of the food pyramid, a prehistoric beast weighing 450 kg, more robust and larger than not only its relative the Smilodon fatalis, but also that their "oppressor" of the north, the Cave Lion North America.
Two species maintained their reigns until a few thousand years ago, our ancestors probably met them, and some were killed in confrontations with these powerful animals: The Lion cave in the north and Sabretooth in the south.