Scientists usually divide the Cat (Felids) Family into two major groups – True Cats and Saber-toothed Cats. Since Cat evolution is murky at times, various cat-like animals have been sketched in to complete the line. One problem with this is that in prehistory the popular body type for cat-like carnivores was a stocky one with saber teeth.
The major characteristic of the Saber-toothed Cat Sub-family is their long canines (saber teeth). Because these specialized teeth could break on bone, these Felids, usually wrestled their prey to the ground before killing the unfortunate animal. To be successful predators, They also had unusually powerful forelimbs.
Saber-toothed Cats were further divided into Dinofelis (an early Felid), Megantereon (predecessor to Smilodon), Scimitar Cat (Homotherium), Smilodon (Saber-toothed Cat) and Xenosmilus (found in Florida). The body types of Machairodontinae ranged from the hyena-like Scimitar Cats to the more massive Smilodons. These Felids were a successful group of carnivores who dominated in prehistoric times. First emerging during the Miocene epoch (eight million years ago), Saber-toothed Cat Sub-family went extinct about 10,000 years ago at the end of the Ice Age. Climate change, the expanding grasslands, and smaller faster prey spelt the end of this Sub-family.
At one time, the reason given for the demise of these Felids was that their long teeth evolved to become too long. Either these Predators could not close their mouths or their teeth grew into their jaws. However, all these reasons together comprise an urban legend.
Like all urban legends, it may seem true at first glance, and make logical sense. However, when you start to look into the matter, you first grasp that these Felids were never Rodents (whose teeth grow throughout their lives). Upon further reflection, the idea that Saber-toothed Cat Sub-family could not close their mouths is utter nonsense.
The Saber-toothed Cat Sub-family invites us to examine closely anything that seems to be true. We should not accept things on face value and repeat them. Like urban legends that spread like wildfire by unthinking people, we tend to repeat what nonsense we hear. Like these predators, we need to be skeptical of everything that does not make sense. “If it does not make sense, then it is not true.” --Judge Judith Sheindlin.