Speculation on the pack-hunting habits of "Albertosaurus" were made by a few researchers who suggest that the younger members of the pack may have been responsible for driving their prey towards the adults, who were larger and more powerful, but also slower. Juveniles may also have had different lifestyles than adults, filling predator niches between those of the enormous adults and the smaller contemporaneous theropods, the largest of which were two orders of magnitude smaller than an adult "Albertosaurus" in mass. However, as the preservation of behavior in the fossil record is exceedingly rare, these ideas cannot readily be tested. Phil Currie speculates that the "Daspletosaurus" formed packs to hunt, although this cannot be stated with certainty. There is no evidence of such gregarious behavior in "Gorgosaurus".