Science says sabre-toothed cats didn't get their long teeth until they grew up

This fossilized jaw of an adult Smilodon fatalis shows the fully erupted canine. Image: AMNH/J. Tseng

Researchers have found the dagger-like teeth of the sabre-tooth cat emerged later in life than their modern relatives but grew at double the rate.

Previously, little was known about the growth rates of the cats which went extinct around 10,000 years ago in North and South America.

The scientists say the techniques they have developed could be applied to a variety of extinct species, such as the tusks of extinct elephants, to learn how they grew.

Using specimens recovered from the La Brea Tar Pits in Los Angeles, the researchers combined data from stable oxygen isotope analyses, micro-computed tomography and previously published studies to establish the eruption rate for the cat’s permanent upper canines.

The study estimates that most permanent teeth took 14 to 22 months to come through but the upper canines took longer.

These weren’t fully developed until about three years of age, which is delayed in comparison to similar-sized living members of the cat family.

The eruption rate of the sabre-toothed cat’s permanent upper canines was 6 millimetres a month, or about the growth rate of an African lion’s teeth. They grew to about 17 cms in length.

“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,” says lead author Aleksander Wysocki of Clemson University.

The study is published in the journal PLOS ONE.

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