While it generally remains controversial, evidence does exist that supports the theory that at least some tyrannosaurids were social. In British Columbia's Wapiti Formation, a trackway composed of the footprints of three individual tyrannosaurids (named as the ichnogenus "Bellatoripes fredlundi") was discovered by a local outfitter named Aaron Fredlund and described in the journal PLOS One by Richard McCrea et al. An examination of the trackway found no evidence of one trackway being left long after another had been made, further supporting the hypothesis that three individual tyrannosaurs were traveling together as a group. Further research revealed the animals were traveling at a speed of between and likely had a hip height of around 7 to 9 feet. As three different genera of tyrannosaurids ("Gorgosaurus", "Daspletosaurus", and "Albertosaurus", respectively) are known from the formation, it is unknown which genus was the maker of the trackway.