In the La Brea Tar Pits, few of the recovered Saber Tooth Tiger skulls still have the sabers attached. But in the batch that had the sabers, a handful exhibited a peculiar feature: the tooth socket for the saber was occupied by two teeth, with the permanent tooth slotted into a groove in the baby tooth. Paleontologist Jack Tseng, Associate Professor in the Department of Integrative Biology, doesn’t think the double fangs were a fluke. Read more in this Berkeley news article linked here.
The above image is of a mechanical analysis of the distinctive canines of California's saber-toothed cat (Smilodon fatalis) suggests that the baby tooth that preceded each saber stayed in place for years to stabilize the growing permanent saber tooth, perhaps allowing adolescents to learn how to hunt without breaking them. Courtesy of Massimo Molinero.