Saber-Toothed Cat, also known as saber-toothed tiger, extinct cat with a powerful body about the size of a lion. Saber-toothed cats had long canine teeth shaped like sabers (curved daggers) in the upper jaw. They could open their mouth very wide, and they used their canine teeth to strike down prey. Fossil remains indicate that saber-toothed cats lived in both the Eastern and Western hemispheres beginning about 40 million years ago. They became extinct around 11,000 years ago.

Scientists have identified the fossils of three kinds of saber-toothed cats that coexisted in North America. Probably the best known was the Smilodon, recognized by its long, finely serrated canine teeth up to 18 cm (7 in) long. Its short, muscular legs provided power but not speed. The Smilodon probably ambushed slow-moving prey, such as mastodons, from a hiding place. It used its sharp teeth to deliver a fatal wound to the belly or throat of its prey. Another type of saber-toothed cat, the Homotherium, roamed Africa, Eurasia, and North America. Built more like a cheetah, its long forelimbs, shorter, powerful hindlimbs, and long neck enabled the Homotherium to move with great speed to chase prey. It had short, coarsely serrated teeth about 10 cm (4 in) long that it used in killing prey. In 1999 scientists found fossils of a previously unknown type of saber-toothed cat in Florida. Named Xenosmilus, this cat had the shorter, serrated teeth of a Homotherium and the short, massive limbs of a Smilodon. Scientists believe Xenosmilus was an ambush predator that appeared more bearlike than catlike.

Scientific classification: Saber-toothed cats belong to the cat family, Felidae, in the carnivore order, Carnivora.