Size and Weight:
About the Giant Hyena (Pachycrocuta):
It seems that every creature on earth came in larger packages during the Pliocene and Pleistocene epochs, and the Giant Hyena (genus name Pachycrocuta) was no exception. This megafauna mammal was very similar to the modern Spotted Hyena, except that it was about three times the size (some individuals may have weighed as much as 400 pounds) and more stockily built, with comparatively shorter legs. (In this respect, the Giant Hyena was similar to its close contemporary Smilodon, the "saber-toothed tiger," which was also much bulkier and slower than modern big cats.)
Save for those crucial differences, though, the Giant Hyena followed a recognizably hyena-like lifestyle, stealing freshly killed prey from other, presumably smaller, predators and occasionally hunting for its food. Tantalizingly, the fossils of some Pachycrocuta individuals have been found in the same Chinese caves as the modern human ancestor Homo erectus; however, it's unknown if Homo erectus hunted the Giant Hyena, if the Giant Hyena hunted Homo erectus, or if the two populations merely occupied the same caves at different times!