The idea of facing down one angry Tyrannosaurus rex is scary enough—but new research from a mass death site uncovered in Utah seven years ago suggests that they may have hunted together in packs like wolves. Paleontologists developed the theory while studying the site at the Grand Staircase-Escalante National Monument in southern Utah, where an unusually high number of T. rex remains were discovered together in 2014. Using geochemical analysis of the bones and surrounding rock, a team of researchers from the University of Arkansas has determined that the dinosaurs died together at roughly the same period of time. Philip Currie said: “Undoubtedly, this group died together, which adds to a growing body of evidence that tyrannosaurids were capable of interacting as gregarious packs.” Joe Sertich, curator of dinosaurs at the Denver Museum of Nature & Science, said: “This discovery should be the tipping point for reconsidering how these top carnivores behaved and hunted across the northern hemisphere during the Cretaceous.”