Saber-tooth Cats
Saber-tooth cats are carnivores found in many of the mountainous or snow bound lands of Middle-earth. The most obvious feature are the fang like teeth projecting below their jaws, and they come in many colors and patterns. They are not actually cats, being a related family. However in common usage some cats such as leopards and lions are considered to be saber-tooth cats.
Sabre-tooth cats are very aggressive, are often pets to other ancient bipeds such as giants and snow-beasts, and they do not seem to be aligned with the rising evil unless they are allied to something that is.
Note for journal keepers
For the brave souls keeping journals of what they see in their travels, these beasts should be recorded as sabertooth.
This is a listing from the journals of known forms of this beast: