[ClearCase_guy]

I believe the short-faced bears may have been carrion eaters. The thinking is that they had a highly developed sense of smell -- typical in those animals that ate rotting meat. The benefit of their large size was to scare off other carrion eaters from a food source.

But I think this stuff generally falls into the area of "unsubstantiated guesswork".

[exDemMom]

But I think this stuff generally falls into the area of "unsubstantiated guesswork".

No, these are "educated guesses", in which various clues like the wear patterns on the teeth, types of teeth, fossilized scat, claw types and wear patterns, etc., provide evidence about the diet of the animal involved. These characteristics can be compared to those of currently living species to build a picture of what the ancient animals were like.