What is it that makes Sinornithomimus different from all of the other ornithomimid theropods? These dinosaurs, generally speaking, are very similar overall. They all appear to be cursorial and omnivorous animals that lived in some sort of herd structure. In that respect they are not much different from hadrosaurs, except that they probably had a more insect based diet. The herding mentality of the dinosaur is what really led to the marvel of the dinosaur. Fossil beds of mass graves tend to have that effect for some reason. The fact that Sinornithomimus was discovered intertwined in a mass of bodies is not new to paleontology by any means, this happens somewhat often, considering the rarity of fossils to begin with. The herds in China and Mongolia of ornithomimids like Sinornithomimus may have looked something like this, though, and it is interesting to imagine it.