While some scientists argue that Deinonychus was a pack-hunting dinosaur, not all paleontologists agree with this assertion, though there is some isolated fossil evidence showing multiple Deinonychus specimens fossilized with a much larger prey dinosaur species. This evidence may establish that there was at least one instance of Deinonychus attacking the same prey, which was arguably too large to be taken down by a single Deinonychus, but that evidence is not sufficient for all experts in the field to agree that this dinosaur was definitely a pack hunter. There is additional evidence to support this idea, including multiple fossil sites suggesting that Deinonychus regularly fed on this larger dinosaur, the Tenontosaurus.

These Deinonychus fossil sites were all excavated by the team of a single paleontologist, John Ostrom, who first discovered Deinonychus fossils in Montana in 1969. Ostrom is the main proponent of the idea that Deinonychus were pack hunters. However, some paleontologists propose other ways of interpreting the fossil evidence. For example, in 2007, two paleontologists posited that the evidence could show that Deinonychus were vicious in their defense of prey, even going so far as to kill other members of its species to protect its meal from scavengers. This is just one example of the difficult job paleontologists face in interpreting information from limited fossil data.