Saber–toothed cat

Smilodon skull. Illustrates the huge gape of its sabretooth jaws. This is the larger species, Smilodon populator

The skull of Hoplophoneus, a Nimravid, showing the jaw flange which helped to protect the sabre-like teeth

Barbourofelis

Thylacosmilus atrox skull

Smilodon skull and upper cervical vertebrae

The saber–toothed cats or sabre-tooth cats are some of the best known and most popular extinct animals. They are among the most impressive carnivores that ever have lived. These cats had long canine teeth and jaws which opened wider than modern cats'. This suggests a different style of killing from modern felines.

There are none living today: they are extinct. The extinctions followed climate change, as the world cooled and grassland took over from woodland in the Pliocene and Pleistocene epochs.

Convergent evolution

The sabre-tooth style of life evolved at least five times amongst carnivorous mammals. This is one of the best-known examples of convergent evolution.

Creodonts

Creodonts were the earliest sabre-tooths known to exist. They lived in the Eocene, and are in a different order from the Feliformia. Machaeroides and Apataelurus are examples.

Nimravids

The Nimravids were a basal group in the Feliformia, lasting from the Eocene to the later Miocene epochs. Hoplophoneus is an example.

Barbourofelidae

The Barbourofelidae is another family of Feliforms which developed the sabre-tooth lifestyle. They flourished in the Miocene. They are probably more closely related to the felids than the Nimravids.

Sparassodonts

Sparassodonts, such as Thylacosmilus, were a metatherian group of mammals. They used to be called "marsupial sabre-tooths", but they belong to a sister-group to the marsupials. They existed from the Miocene to Pliocene epochs.

Machairodontinae

The Machairodontinae is a subfamily of the Felidae, lived from the Miocene to the Pleistocene (23 million years ago to 11,000 years ago). This subfamily includes the famous Smilodon.

Nimravides

Nimravides is a member of the Felinae, and not one of the Nimravids.

Hunting behavior

The saber-tooths were ambush predators, and probably lived in open forests. This would explain their widespread occurrence in the Miocene, when much of the land was covered with woodland. Apart from the canine teeth, their adaptations included strength in the forelimbs (more so than present-day large cats). Their robust (heavy, tough) bodies speak of strength rather than speed.

Compared to modern cats, saber-toothed cats' front limbs were longer and stronger. Based on that and the differences in its teeth, scientists believe the saber-toothed cat must have attacked differently than modern cats do. An educated guess would be: they were ambush predators, which clung on round the neck of their prey, and slashed at the underside of the throat.

The fact that their teeth vary is interesting. Some have larger teeth, some had smaller dagger-like teeth, some had smooth thick teeth, others had blade-like teeth, sometimes with serrated edges. Some had flanges on the lower jaw, most did not. Ewer remarks that this must show that there were variations in killing method, and in the type of prey, but we know little about this.