The researchers acknowledge the high rate of tooth breakage reported in the previous study, but they argue that it is more likely the result of increased breakage when taking down prey instead of when feeding.
"Teeth can break from the stress of chewing bone but they can also break when the carnivores take down prey," DeSantis pointed out. Species like hyenas that regularly chew and crack bones of their kills are as likely to break the rear teeth they use for chewing as their front canines. Species like the cheetah, however, which avoid bones during feeding are twice as likely to break canines than rear teeth. This suggests that they are more likely to break canines when pulling down prey.
The researchers report that previous examinations of the jaws of the American lions and saber-tooth cats from this period found that they have more than three times as many broken canines and interpret this as additional evidence that supports their conclusion that most of the excess tooth breakage occurred during capture instead of feeding.
In addition, the researchers argue that the large size of the extinct carnivores and their prey can help explain the large number of broken teeth. The saber-toothed cats were about the size of today's African lion and the American lion was about 25 percent larger. The animals that they preyed upon likely included mammoths, four-ton giant ground sloths and 3,500-pound bison.
Larger teeth break more easily than smaller teeth. So larger carnivores are likely to break more canine teeth when attempting to take down larger prey, the researchers argue. They cite a study that modeled the strength of canine teeth that found the canines of a predator the size of fox can support more than seven times its weight before breaking while a predator the size of lion can only support about four times its weight and the curved teeth of the saber-toothed cats can only support about twice
|Contact: David Salisbury|