Machairodus was a genus of large, machairodontine saber-toothed cats that lived in Europe, Asia, Africa and North America from approximately 13 million years ago to 2 million years ago. Species of Machairodus expressed great variation in size and proportions, with the largest being about the size of a lion. They all possessed serrated edges on their large canine teeth, though these wore down within a few years of the creature's life. It is the likely ancestor of the genus Homotherium. Machairodus was itself descended from Proailurus, as were all true cats.