Dinosaur senses primitive birds like "Archaeopteryx" and "Hesperornis". The optic nerve was large in "Carcharodontosaurus". Among dinosaurs, theropods had exceptionally large eyes. Deinonychosaurians, especially troodontids, had forward-facing eyes, suggesting stereoscopic vision and improved depth perception. Tyrannosauroid snouts allowed for a 55˚ binocular field of view, less than a modern human but more than their hadrosaurid prey. Dinosaur senses Dinosaur senses are difficult subjects of study for paleontologists since soft tissue anatomy rarely fossilizes. The three semicircular canals of the inner ear of "Allosaurus fragilis", when viewed from the side, had a subtriangular outline. This subtriangular inner ear configuration is present in "Carcharodontosaurus",
Specimens of Archaeopteryx its aerodynamic function as a flight feather. As the feather bears little resemblance to the retrices of the other full "Archaeopteryx" skeletons, it is generally thought to be a wing feather: Griffiths and others have concluded it was a remex, while Carney in 2012 interpreted it to be a covert feather. The feather has a relatively low degree of asymmetry, which Speakman and Thompson in 1994 concluded to indicate it as a secondary remex. If this is the case, then it would have originated from an animal smaller than even the Eichstätt specimen, which is the smallest "Archaeopteryx" specimen known