The Forsaken

The Dromaeosaurids, or "Raptor" family, were certainly prosperous, first appearing around 120 million years ago and diversifying and spreading until the end of the Cretaceous period. Even so, it is highly unlikely that their efficacy as hunters had anything to do with their intelligence. They were smart for dinosaurs, but that still only puts them on the level of today's largest reptiles and birds. Even Deinonychus, a creature well-advertized as a sharp-witted killing machine able to hunt in coordinated packs, only did so on rare occasion and were hardly organized.
The more plausible option is that several individuals would have been drawn to the same prey (perhaps an elderly Tenontosaurus) by sheer chance. Their combined force would have been enough to bring such a large prey item down, but once killed, the corpse would be given first to those willing to fight for it. While hunting is a challenge on its own, surviving to adulthood requires surviving the challenge of older, stronger members of your own species.
The nobility of the dinosaurs: fascination abounds.

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