New research technique assigns ages to Smilodon fatalis developmental events, shows rapid canine growth but overall delayed dental maturity
Date: July 1, 2015
Source: American Museum of Natural History
New research shows that the fearsome teeth of the saber-toothed cat Smilodon fatalis fully emerged at a later age than those of modern big cats, but grew at a rate about double that of their living relatives. The findings, published today in the journal PLOS ONE and based on a new technique that combines isotopic analysis and x-ray imaging, for the first time provide specific ages for developmental events in Smilodon, notably in their teeth. The study estimates that the eruption rate of S. fatalis's permanent upper canines was 6 millimeters per month--double the growth rate of an African lion's teeth. But the extinct cat's dagger-like canines weren't fully developed until about three years of age.
"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. "This is especially crucial for understanding sabertoothed predators such as Smilodon."
S. fatalis lived in North and South America until going extinct about 10,000 years ago. About the size of a modern tiger or lion but more solidly built, the cats are famous for their protruding canines, which could grow to be 18 centimeters (about 7 inches) long. Although well-preserved fossils of S. fatalis are available to researchers, very little is known about the absolute ages at which the animals reached key developmental stages.
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