The sabertooth tiger or smilodon
The sabertooth tiger or smilodon is often known as the ancestor of the tiger, nevertheless he is not. Still they are related, because they are members of the same family, the felidae (big cats) but their genus is different.
The full name of the sabertooth tiger is Animalia Chordata Mammalia Carnivora Felidae Smilodon X. In ordinary language: Animals, Chorda animals, Mammals, Carnivores, Big cats, Smilodon, X. The subfamily is the Machairodontinae, that were later replaced with the Panterinae, the subfamily of the modern tigers.
Smilodon is only the genus. So we can subdivide the smilidon in 3 species:
Food and behaviour
The sabertooth tiger mainly feeds himself with tall protozoa: bison, deer, elk, wild horses, mastodons and young mammoths. So his hunting techniques fit this kind of prey, which is very different to tigers, because they aim for smaller prey. This difference is most obvious in the very long canine teeth of the sabertooth tiger (with the Smilodon Populator they even could grow as long as 28 cm). This difference results in a totally different hunting technique. The smilodon uses his forelegs to take down his prey. Next he uses his long canine teeth to perforate the artery in the neck, which results in a very quick death. Unlike the modern tiger, he doesn't asphyxiate his prey, because his teeth are too fragile and delicate. Because his prey consists only of the bigger animals, that's probably the reason why he became extinct, once they were no longer available.
The species
Smilodon Gracilis
This species lived 2,5 million till 50 000 years ago (in the Pliocene and the Pleistocene). Scientists suspect that the other 2 species originated from this one. It's the smallest and slightest (55 till 100 kg) from the three.
Smilodon Fatalis
This species lived 1,6 million till 10 000* years ago (in the Pleistocene). This species occurred in what's now North America and SouthWest America. This species is sometimes subdivided in the Smilodon Californicus and the Smilodon Floridus. The Smilodon Fatalis would have weighed between 160 and 220 kg.
Smilodon Populator
This species lived 1 million till 10 000* years ago (in the Pleistocene). The Smilodon Populator occured in Eastern America and was de largest and heaviest (200 till 300 kg average) species of the three.
* End of the Würm, the sixth and last glacial period.
Probably that's the reason why they died out.
