Saber-tooth tigers (Smilodon) were large, predatory cats that lived in the Americas and Eurasia during the Pleistocene epoch. They are part of the Felidae family, which also includes lions, tigers, leopards, and cheetahs.
Bears belong to the Ursidae family and are more closely related to seals and sea lions than to cats. They evolved from a common ancestor that lived about 35 million years ago.
While both saber-tooth tigers and bears were apex predators, they evolved independently along different branches of the evolutionary tree. They share a common ancestor much further back in time, but their lineage diverged millions of years ago.