Fossils may prove T-rex lived in packs AP, SALT LAKE CITY Tyrannosaur dinosaurs might not have been solitary predators as long envisioned, but more like social carnivores such as wolves, new research unveiled on Monday found. Paleontologists developed the theory while studying a mass tyrannosaur death site found seven years ago in the Grand Staircase-Escalante National Monument in southern Utah, one of two monuments that the administration of US President Joe Biden is considering restoring to their full size. Using geochemical analysis of the bones and rock, a team of researchers with the University of Arkansas determined that the dinosaurs died and were buried in the same place and were not the result of fossils washing in from multiple areas.