Size and Weight:
The name Sinraptor is misleading in two ways. First, the "sin" part doesn't mean this dinosaur was evil; it's simply a prefix meaning "Chinese." And second, Sinraptor wasn't a true raptor, a quick, fierce family of carnivorous dinosaurs that didn't arrive on the prehistoric scene until tens of millions of years later. Rather, Sinraptor is believed to have been a primitive allosaur (a type of large theropod) that was ancestral to such giant predators as Carcharodontosaurus and Giganotosaurus.
Based on when it lived, paleontologists have concluded that Sinraptor (and other allosaurs like it) preyed on the juveniles of the gigantic sauropods of the late Jurassic period. (The open-and-shut case: sauropod fossils have been discovered in China bearing the unmistakable imprint of Sinraptor tooth marks!)