Known as "saber-toothed tigers," the extinct cats roamed the Americas until about 10,000 years ago, preying on large animals.
Scientists say the conical shape of their elongated teeth inferred saber-toothed cats killed their prey differently from other felines because their teeth were thinner from side to side, said Julie Meachen-Samuels, a paleontologist at the National Evolutionary Synthesis Center in Durham, N.C., and author of an article in the journal PloS ONE.
"Cats living today have canines that are round ... so they can withstand forces in all directions," Meachen-Samuels said in a NESCenter release.
However, muscle attachment scars on the extinct cats' limb bones suggest it was powerfully built, Meachen-Samuels said. Saber-toothed cats may have used their muscular forelimbs to immobilize prey and protect their teeth from fracture.
Researchers used X-rays to measure the cross-sectional dimensions of the upper limb bones of fossils recovered from the La Brea Tar Pits in Los Angeles. They also measured limb bones of 28 cat species living today and the extinct American lion, the largest conical-toothed cat that ever lived.
Meachen-Samuels said the saber-toothed cat's arm bones were larger in diameter and had a thicker cortical bone.
"As muscles pull on bones, bones respond by getting stronger," she said. "Because saber-toothed cats had thicker arm bones we think they must have used their forelimbs more than other cats did."