Homotherium

Homotherium is an extinct genus of scimitar-toothed cat belonging to the extinct subfamily Machairodontinae that inhabited North America, Eurasia, and Africa, as well as possibly South America during the Pliocene and Pleistocene epochs from around 4 million to 12,000 years ago. A probable descendant of Amphimachairodus, it was one of the last surviving members of Machairodontinae alongside the more famous sabertooth Smilodon, to which it was not particularly closely related. It was a large cat, comparable in size to a lion with a body mass of up to 200 kilograms (440 lb), functioning as an apex predator in the ecosystems it inhabited. It had an elongate neck and relatively elongate legs, a relatively short back and a very short tail, with the mummy of a H. latidens cub of Late Pleistocene age found in Siberia having a plain dark brown coat colour. In comparison to Smilodon, the canines of Homotherium were shorter, though still longer than those of living cats, and it is suggested to have had a different ecology from Smilodon as a moderate speed endurance pursuit predator adapted to running down large prey, such as antelope, equines, bovines, and juvenile mammoths in open habitats, with Homotherium also proposed to have likely engaged in cooperative hunting.

Once widely distributed over most of the world's continents, the genus saw a protracted decline over the course of the Pleistocene, disappearing from Africa during the Early Pleistocene around 1.5 million years ago, and declining in abundance and distribution in Eurasia during the Middle Pleistocene, though with a handful of records in the Late Pleistocene. In North America, the genus survived until the end of the Late Pleistocene around 12,000 years ago, becoming extinct as part of the end-Pleistocene extinction event along with most other large animals native to the Americas. This followed the arrival of humans into the Americas, who may have caused a decline in populations of large prey on which Homotherium depended.

Research history and taxonomy

Eurasia

The first fossils of Homotherium were scientifically described in 1846 by Richard Owen as the species Machairodus latidens, based on Pleistocene aged canine teeth found in Kent's Cavern in Devon, southwestern England by the Reverend John MacEnery in 1826. The name Homotherium (Greek: ὁμός (homos, 'same') and θηρίον (therion, 'beast')) was proposed by Emilio Fabrini in 1890 during a review of machairodont material from the Late Pliocene-Early Pleistocene of Tuscany, Italy, without further explanation, for a new subgenus of Machairodus, whose main distinguishing feature was the presence of a large diastema (gap) between the two lower (inferior) premolars.