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Machairodontinae
Smilodon californicus fossil at the National Museum of Natural History, Washington, DC
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Carnivora Family: Felidae Subfamily: Machairodontinae Gill, 1872
Tribes
Metailurini Homotheriini Smilodontini

The Machairodontinae form a subfamily of the Felidae (true cats). It contains some of the extinct cats commonly known as "saber-toothed cats", including the famed genus Smilodon as well as other cats with only minor increases in the size and length of their canine teeth.

Contents 1 Teeth 2 Relationship with other cats 3 Habitat 4 Hunting techniques 5 References

Machairodonts are divided into two types: dirk-toothed and scimitar-toothed. Dirk-toothed cats had elongated, narrow upper canines and generally had stocky bodies. Scimitar-toothed cats had broader and shorter upper canines and a typically lither form with longer legs. The longer-toothed cats often had a bony flange that extended from their lower mandible. However, one genus, Xenosmilus, broke this mould, possessing both the stout heavy limbs associated with dirk-toothed cats, and the stout canines of a scimitar-toothed cat.

The name 'saber-toothed tigers' is misleading. Machairodonts were not even in the same subfamily as tigers, there is no evidence that they had tiger-like coat patterns, and this broad group of animals certainly did not all live or hunt in the same manner as the modern tiger. DNA analysis published in 2005 confirmed and clarified cladistic analysis in showing that the Machairodontinae diverged early from the ancestors of modern cats and are not closely related to any living feline species.

It is commonly thought that saber-toothed cats lived only in cold areas caused by an ice age. While some certainly did live in snowy conditions during an ice age, the history of Machairodonts stretches back into the warmer climates of the Oligocene, and their diversification paralleled the growth of prairie biomes; they became extinct only in the last 10,000 years.

The method by which machairodonts hunted is hotly debated. It was originally thought that they used a 'stabbing' motion with their teeth (dropping their jaws wide open, baring their teeth, and thrashing downward). However, this is now considered unlikely, for the teeth, being so long, were fragile, and a large prey animal thrashing about could easily injure the teeth, which would impair hunting. Some scientists suggest that the cats slashed at the bellies of large animals with their teeth and waited for them to die of blood loss, although the risk of breakage would still be high. When the bite of a dirk toothed cat is matched against the neck of a large ungulate, however, it shows that the bite would sever all arteries and veins, while acting as a clamp around the windpipe. This method would still have been risky for the teeth if the prey moved too much, but less risky than the stabbing method; with the neck bite, the cat would be anchored with its incisors and lower canines. Also, if the cats worked in prides (there is evidence that some species may have), they could have subdued the animal before performing the killing bite.

• Report on Barnett group's study in Current Biology August 9, 2005: Ross Barnett et al.: "Evolution of the extinct Sabretooths and the American cheetah-like cat" in Current Biology, Vol. 15, R589-R590, August 9, 2005