Saber-toothed tiger or Sabre-toothed cat refers to the extinct subfamilies of Machairodontinae (Felidae), Barbourofelidae (Feliformia), and Nimravidae (Feliformia) as well as two families related to marsupials that were found worldwide from the Eocene Epoch to the end of the Pleistocene Epoch (42 mya—11,000 years ago), existing for approximately 42 million years.
They are so called for their large, saber-like maxillary canine teeth, which extended from their mouths even when it was closed. Despite the name, not all animals known as saber-toothed cats were closely related to modern felines. The Nimravidae are the oldest, entering the landscape around 42 mya and becoming extinct by 7.2 mya. Barbourofelidae entered around 16.9 mya and were extinct by 9 mya. These two would have shared some habitats.