Sabertooth
The term saber-toothed” is a generic term used to describe many species of mammals with huge canines that lived during different epochs of the Cenozoic.
These species acquired their characteristic saber teeth completely independently. Tooth morphology can be considered as an example of convergent evolution, since it has occurred repeatedly and independently in at least four different groups of mammals: the macarodonts (Machairodontinae), a subfamily of felids that includes the famous Smilodon; the nimravids (Nimravidae), a family related to the cats, but different; and finally, a couple of isolated cases within the creodonts (which are not considered true carnivores) and the thylacosmylids, an extinct family of South American metatherians.
Featured Genres
| Gender | Number of species | Period | Regions |
| Smilodon | 4 | 2.5 million years (Ma) to 10,000 years ago | North and South America |
| Hoplophoneus | 5 | 33.7 Ma to 23.8 Ma back | North |
| Homotherium | 1 | 3 Ma to 10,000 years ago | Eurasia, Africa, North America |
| Thylacosmilus | 1 | 10 Ma to 1.8 Ma back | South America |
| Metailurus | 1 | 15 Ma to 8 Ma before | China and Eastern Europe |
| Machairodus (ance of Homotherium) | 5 | 15 Ma to 2 Ma before | Africa, Eurasia and North America |
| Megantereon | 2 | 3 Ma to 9,000 years old | Africa, Eurasia and North America |
| Dinofelis | 5 | 5 Ma to 1.5 Ma before | Africa, Eurasia and North America |
| Paramachairodus | 2 | 20-15 Ma to 9 Ma before | Spain |
| Xenosmilus | 1 | 1 Ma before | Central Florida |
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Evolutionary tree
All saber-toothed mammals lived between 9,000 and 33,700,000 years ago, yet the evolutionary lines that gave rise to the saber-toothed genera began to diverge much earlier.
- Class Mammalia
- Subclass Marsupialia (date of unknown divergence, during the Cretaceous).
- Order Sparassodonta (an extinct group of South American metateria).
- Thylacosmilidae family (borhienoids with sable teeth).
- Anachlysictis
- Patagosmilus
- Thylacosmilus
- Order Sparassodonta (an extinct group of South American metateria).
- Subclase Placentalia
- Creodonta (divided about 60 million years ago in the Paleocene).
- Hyaenodontidae
- Apataelurus
- Machaeroid
- Hyaenodontidae
- Order Carnivora
- Nimravidae family (was separated from the feliforms between 48 and 55 million years earlier, in the Late Eocene).
- Hoplophoneus
- Felidae family (true felines).
- Subfamily Machairodontinae (date of unknown divergence).
- Tribu Machairodontini
- Homotherium
- Machairodus
- Xenosmilus
- Metailurini
- Dinofelis
- Metailurus
- Tribu Smilodontini
- Megantereon
- Paramachairodus
- Smilodon
- Tribu Machairodontini
- Subfamily Machairodontinae (date of unknown divergence).
- Nimravidae family (was separated from the feliforms between 48 and 55 million years earlier, in the Late Eocene).
- Creodonta (divided about 60 million years ago in the Paleocene).
- Subclass Marsupialia (date of unknown divergence, during the Cretaceous).
Features
The most spectacular and obvious attribute of all saber-toothed mammals are the huge upper canines. Although the general consensus according to their teeth is that they were used for hunting, thereby denoting a carnivorous diet, the exact way in which they were used has been a matter of debate since the 1880s, when the Smilodon was first described.
Support
Some paleontologists believe the primary purpose was to grab and hold large prey. The evidence however does not give sufficient support to this theory, since it has been shown that such long teeth used in this way could break easily, and fossil skulls with broken teeth are rare.
Slashed
A more widely accepted hypothesis suggests that sabertooths were used to bite into the throat or abdomen of large prey (Akersten, 1985), or to cause deep puncture wounds that would bleed the animal.
Exhibit
Another possible use is as a social status structure, like almost all antlers. If so, this would support the theory that sabertooths were social animals or perhaps strongly territorial.