Researchers say the saber-toothed cat Smilodon fatalis lived in America during the Pleistocene before getting extinct 10,000 years ago. The researchers said sabers were used by Smilodon to slit the throat of its prey. Findings of the study have been published in the journal PLoS ONE.

The research focused on how the sabers developed. It was found that the size of sabers increased almost twice as fast as modern lion canines.

Jack Tseng, co-author on the paper and a paleontologist at the American Museum of Natural History, said these prehistoric killing machines are fascinating.

Tseng said the sabers are such an extreme adaptation that many are of the belief that they are evolutionary show-offs.

Fossils from the La Brea Tar Pits in Los Angeles were reviewed by Tseng and his colleagues, including Robert Feranec. The researchers figured out after doing meticulous analysis of the chemical composition and structure of the sabers that size of the extinct cat's sabers grew 6 mm per month. The speed was twice as fast as human fingernails.

Tseng said gaining insight into the growth rates and timing of development will help understand the lifestyles of these extinct animals.

"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", said study lead author Aleksander Wysocki.

The researchers say the technique used by them for the study has paved the way for understanding the growth rate of other extinct species.