SABRE-TOOTHED CAT

any of the extinct carnivores forming the subfamily Machairodontinae of the cat family, Felidae. Sabre-toothed cats are named for the pair of elongated, bladelike canine teeth they possessed in the upper jaw. They are often called sabre-toothed tigers or sabre-toothed lions, although the lion and tiger are of a different subfamily of felids, the true cats (Felinae). Sabre-toothed cats existed from the Oligocene through the Pleistocene epochs (36,600,000 to 10,000 years ago). They were present in North America and Europe throughout the Miocene and Pliocene epochs (23.7 to 1.6 million years ago); by Pliocene times they had spread to Asia and Africa; and in the Pleistocene they were present in South America. The most widely known of the sabre-toothed cats is the Pleistocene Smilodon, which represented the peak of sabre-tooth evolution. A large, short-limbed cat of North and South America, it was more massive than the modern lion. Its immense upper canine teeth, up to 20 cm (8 inches) long, probably were used for stabbing and slashing attacks, possibly on large herbivores such as the mastodon. Such a hunting technique is suggested by several physical adaptations of Smilodon: its skull was modified to accommodate the attachment of strong neck muscles for bringing the head down; the lower canines were reduced; and the jaw could be opened to about a 90 angle to free the upper canines for action. The molar teeth formed shearing blades with no traces of grinding surfaces. The bones of many members of this genus have been recovered from the tar pits of Rancho La Brea, in Los Angeles, where the sabre-tooths were trapped in the tar, apparently as they preyed on large herbivores that had also become entrapped. The basic sabre-tooth characters were present, but less fully developed, in a Smilodon ancestor, Hoplophoneus, a moderately sized felid of the North American Oligocene. The pattern of extinction of the sabre-toothed cats closely followed that of the mastodons. As these large, elephant-like animals became extinct in the late Pliocene of the Old World, the sabre-tooths died out also. In North and South America, where mastodons persisted throughout the Pleistocene, sabre-tooths continued successfully to the end of the epoch. The sabre-tooths were highly specialized felids forming an evolutionary line distinct from that of the modern cats at least since the Oligocene. Some early forms are of doubtful standing and have been classified as true sabre-tooths (Machairodontinae), false sabretooths (Nimravinae), or true cat (Felinae), depending on the authority. One such form, Dinictis of the North American Oligocene, had fairly well-developed, sabrelike teeth but in general lacked the other specialized features of the true sabre-tooths. It has been suggested that Dinictis-like animals were part of the evolutionary line leading to the true cat.