Saber-Toothed Cat: Ultra-Sharp Teeth Slow to Emerge

Saber-tooth tigers had African lions beat, when it came to the growth rate of their dagger-like teeth, which was 6 mm a month--comparing favorably with the growth rate of human fingernails at 3.4 mm a month. But the prehistoric cats' teeth took much longer to fully emerge--not being entirely present until the predator was three years old, according to a release from the American Museum of Natural History.

Researchers' findings appeared this week in the journal Plos One, based on a technique that combines isotopic analysis and x-ray imaging, providing new info on the long-ago Smilodon fatalis.

The tiger, Smilodon fatalis, went extinct around 10,000 years ago and was about the size of a modern tiger or lion, but blockier. They lived in North and South America. Their canines, their most famous feature, could grow to be about 7 inches long, according to the release.

"For predators such as big cats, an important determinant of an individual's full hunting ability is the time required to grow their weapons--their teeth," said Z. Jack Tseng, a National Science Foundation and Frick Postdoctoral Fellow in the American Museum of Natural History's Division of Paleontology and a coauthor on the new paper, according to Eurekalert. "This is especially crucial for understanding sabertoothed predators such as Smilodon."

The scientists used S. fatalis specimens recovered from the La Brea Tar Pits in Los Angeles to conduct their research, according to the release.

The technique they demonstrate in the journal could be applied to a variety of extinct species to better understand the manner and rate at which other extinct animals grew, the scientists say, according to the release.