Smilodon (Smilodon fatalis)

Order: Carnivora

Family: Felidae

Smilodon fatalis, perhaps the most well known of all the saber-toothed cats, was a larged powerful feline predator that dominated the western coast of North America during the last ice age. Smilodon is not only the best known but also the most recent in the fossil record, existing as recent as 10,000 years ago. Scientists know more about Smilodon than any other extinct species of cat. The remains of more than 2200 individuals have been excavated from the Rancho La Brea tar pits of California alone.

The life style and social behavior of Smilodon are speculative. The study of modern feline species can offer scientist only clues but no definitive answers. Whether Smilodon individuals lived in prides and hunted in packs or had a more solitary existence can only be surmised at and probably depended on their habitat. If their primary environment was more of an open terrain, cooperative pack hunting might have been a more successful adaptation, but if they were living and stalking prey in more closed terrain, where ambush and surprise were necessary, a more solitary existence would have been more likely.

The habitat would have also influenced their life appearance. Smilodon species, like all modern cats, would have had distinct facial markings important during encounters with other members of the species for communication or mating. Also like modern felines, they would have had some sort of natural camouflaging, manifested as patterns of spots, stripes, or rosettes. Besides the obvious use of the saber-like fangs for hunting, they may have also played a role in breeding, much in the same way modern lions use their manes. Large healthy fangs may have been suggestive of a strong suitor with healthy genes during mate selection.

Smilodon was one of the most successful species of the saber-toothed cats. The reasons for their abrupt extinction some 10,000 years ago are a mystery and can only be theorized. One of the more popular theories suggests that climate and vegetation changes caused the decline of Smilodon's prey animals, which in turn caused the decline of the genus Smilodon. Another popular theory suggests that humans arrived in the New World and hunted Smilodon's prey animals to extinction, so dooming the Smilodon species to the same fate. Even if human encroachment was the cause of their demise, they most assuredly had encounters and would have competed for the same prey. Other known Smilodon species include Smilodon gracilis from the eastern part of North America and a larger, robust species called Smilodon populator from the eastern part of South America.

The ancestors of Smilodon arose in the Old World and are believed to have made their way into North America by way of the Bering land bridge some 18 million years ago. Flourishing upon arrival, ancient cats, or "paleofelids," continued to evolve into a wide variety of diverse species, each with specialized characteristics best suited for its environment. Saber-toothed cats have independently evolved and have undergone extinction throughout many felid blood lines. They were so successful that over the past 11 million years our present time is the only period that has not had a saber-toothed cat in existence.