An extinct, carnivorous, cat-like mammal (family Felidae) in which the upper canine teeth were long, curved, and protruded from the mouth even when the mouth was closed. Smilodon was slightly shorter than a lion but much heavier, and it had a bobtail, suggesting that rather than running down its prey, using its tail for balance, it hunted from ambush. Despite the common name it was not closely related to modern tigers. Smilodon is the best known of the sabre-toothed carnivores, but sabre teeth evolved independently at least twice among the Carnivora, and also among South American marsupials. Palaeontologists believe these animals used their sabre teeth to deliver a single, fatal stab to prey, the predator then waiting for the victim to die. Sabre-toothed cats occurred worldwide from about 42 million until about 11,000 years ago.