Although it has been suggested that Gorgosaurus was a scavenger, its co-existence with the similarly sized, but more robust tyrannosauridDaspletosaurus casts doubt on this theory. Another hypothesis proposes that Gorgosaurus, which was rather lean for a tyrannosaurid, actively hunted fleet-footed animals such as duckbills and ornithomimids ("ostrich-mimic" dinosaurs). According to this proposition, the more troublesome ceratopsians and ankylosaurians (horned and heavily armoured dinosaurs) would have been left to Daspletosaurus. An apex predator, it was at the top of the food chain.