Saber-Toothed Cat's Fearsome Canines Did Not Fully Develop Until Age Three

Posted on July 9, 2015

Partial fossilized jaw from a baby Smilodon fatalis

Scientists have determined that it took time for saber-toothed cats to grow their fearsome protruding canines. The cats were three years old on average before these dagger-like teeth fully developed. Little saber-tooth kittens would not have had them yet. The saber-toothed cat (Smilodon fatalis) went extinct about 10,000 years ago. It lived in North and South American.

The image above is the partial fossilized jaw of a baby Smilodon fatalis. It shows that one of the cat's adult canines was erupting alongside its baby canine at the time of its death. The study was conducted by Aleksander Wysocki and colleagues from Clemson University. The researchers analyzed saber-toothed cat specimens recovered from the La Brea Tar Pits in Los Angeles. They used stable oxygen isotope analyses and micro-computed tomography combined with the results of previous research.

The researchers found the permanent dentition of saber-toothed cats was fully erupted by 14 to 22 months except for the cats' famous canines. These were not fully developed until age three. The researchers say the eruption rate of the saber-toothed cat's permanent upper canines was 6 millimeters per month. This is double the growth rate of the teeth of an African lion. They took a while to erupt but once they did they grew quickly. A Science Mag article says this is about twice the growth rate of human fingernails.

Aleksander Wysocki, the lead author of the study, says in a statement, "Despite having canine crown heights that were more than twice those of the lion, it didn't require twice as much time to develop its canines."

A research paper on the development of canines in saber-tooth cats can be found here in the journal, PLoS One.

Photo: Courtesy of Wysocki, Feranec, Tseng, and Bjornsson


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