Size and Weight:
About the Cave Lion (Panthera Leo Spelaea):
One of the most feared predators of the late Pleistocene epoch, the Cave Lion (Panthera leo spelaea) is technically classified as a sub-species of Panthera leo, the modern lion, a verdict confirmed by genetic sequencing of the Cave Lion's fossil remains. Essentially, this was a plus-sized cat that roamed the vast expanse of Eurasia, feasting on a wide array of mammalian megafauna including prehistoric horses and prehistoric elephants. The Cave Lion was also a voracious predator of the Cave Bear, Ursus spelaeus; in fact, this cat received its name not because it lived in caves, but because numerous intact skeletons have been found in Cave Bear habitats (Cave Lions preyed opportunistically on hibernating Cave Bears, which must have seemed like a good idea until their intended victims woke up! See this article for an analysis of a battle between a den of sleepy Cave Bears and a pack of hungry Cave Lions.)
As is the case with many prehistoric predators, it's unclear why the Cave Lion vanished off the face of the earth about 2,000 years ago. It's possible that it was hunted to extinction by the early human settlers of Eurasia, who would have had a vested interest in banding together and eliminating any Cave Lions in the immediate vicinity (these same humans regarded the Cave Lion with reverence and awe, as evidenced by numerous cave paintings). But it's more likely that the Cave Lion succumbed to a combination of climate change and the disappearance of its usual prey; after all, small bands of Homo sapiens could more easily over-hunt prehistoric deer, pigs and other mammalian megafauna than these huge, fanged predators.