Consequences of Canine Size
Smilodon fatalis has the classic extended, re-curved canines that have made it one of the most popular and studied Pleistocene (2.6 million to ten thousand years ago) predators. These canines are flattened and curved like a sabre sword, hence, the name sabre-tooth tiger. There are no extant mammalian predators with sabre teeth. Modern members of the cat family have conical or cone-shaped canines. There is some evidence that these sabre teeth would have actually presented a number of challenges for Smilodon fatalis and would have made many aspects of feeding much harder than in cats with a traditional set of conical (and much smaller) canines (as in the modern predators today).
The elongation of the canines is coupled with an increase in the overall gape, or maximum opening of the jaw. However, increasing the gape has the effect of drastically reducing bite force, especially at the exaggerated gapes presented by the enormous canines of Smilodon fatalis. In modern predators with a very strong bite force, like hyenas, the point at which the upper and lower jaws join forms an interlocking mechanism that allows considerable bite force. In Smilodon fatalis the point at which the upper and lower jaws join does not form a strong interlocking mechanism. This loose joint would have allowed Smilodon fatalis to open its jaws very wide, but at the expense of being able to clamp their jaws closed on prey. Thus, these canines, which grow increasingly exaggerated as the animal ages, actually decrease the overall bite force substantially, begging the question: how did they eat?