Largest sabre-toothed cat

The largest species of sabre-toothed cat (or machairodont) was Smilodon populator, which lived in South America from around 1 million to around 10,000 years ago, evolving there from an ancestor that migrated across the Panamanian Land Bridge from North America. Based on careful examination of skeletal remains, sabre-toothed cat specialist Mauricio Antón reconstructed the shoulder height of S. populator at 1.2 m (3 ft 11 in); while recent study of an exceptionally large skull found in Uruguay, at 39.2 cm (1 ft 3.4 in) in total length, indicated a predator with a bulk of 436 kg (961 lb). Each of Smilodon’s two flat sabre-like canine teeth measured up to 28 cm (11 in) long, and was wide with serrated edges. These fangs were used to literally go for the jugular, while the cat used its extraordinary bulk to pin down large herbivores with its powerful forelimbs.

By comparison, an unusually large full-grown modern male Siberian tiger (Panthera tigris altaica, the largest living wild cat) may attain a skull length of 38.3 cm (1 ft 3 in), and weigh some 330 kg (728 lb).

Despite the common reference in popular culture, there was no such predator in Earth history as the "sabre-toothed tiger". All sabre-toothed cats belonged to a single completely extinct offshoot of the felid family tree, the machairodonts, with no particular affinity to any living cat species.

A very close contender for S. populator’s crown as the largest ever sabre-tooth lived 7 million years earlier. Amphimachairodus stalked vast parkland-savannahs that stretched from Iberia to China and North Africa 9–5 million years ago, home to massive herds of ancient horses, antelopes, giraffes and rhinos. The partial lower jaw and humerus of a massive Amphimachairodus found in Chad, at over 6 million years old, produced a wide range of body size estimates from 350–490 kg (551–1,080 lb). A very large Amphimachiarodus skull from north-west China’s Gansu Province measures 41.5 cm (1 ft 4.3 in) in total length, with the living animal estimated to have weighed 405 kg (893 lb).

Unlike Smilodon, Amphimachairodus has much shorter, stouter sabres, at a total length of around 21 cm (8.3 in), with 10–13 cm (4–5.1 in) protruding beyond the skull, indicating a quite different habit of prey-killing to Smilodon.