would have sounded somewhat like bird song. However, Russell's thought experiment has been met with criticism from other paleontologists since the 1980s, many of whom point out that his Dinosauroid is overly anthropomorphic. Gregory S. Paul (1988) and Thomas R. Holtz, Jr., consider it "suspiciously human" and Darren Naish has argued that a large-brained, highly intelligent troodontid would retain a more standard theropod body plan, with a horizontal posture and long tail, and would probably manipulate objects with the snout and feet in the manner of a bird, rather than with human-like "hands". Description Stenonychosaurus was a small dinosaur, up to in length and in body mass. The largest specimens are comparable in size to Deinonychus and Unenlagia. They had very long, slender hind limbs, suggesting that these animals were able to run quickly. They had large, retractable, sickle-shaped claws on the second toes, which were raised off the ground when running. Their eyes were very large (perhaps suggesting a partially nocturnal lifestyle), and slightly forward facing, giving Stenonychosaurus some degree of depth perception. Brain and inner ear Stenonychosaurus had one of the largest known brains of any dinosaur, relative to its body mass (comparable to modern birds). This has been calculated as a cerebrum-to-brain-volume ratio 31.5% to 63% of the way from a non-avian reptile proportion to a truly avian one. Additionally, it had bony cristae supporting their tympanic membranes that were ossified at least in their top and bottom regions. The rest of the cristae were either cartilaginous or too delicate to be preserved. The metotic strut of Stenonychosaurus was enlarged from side-to-side, similar to Dromaeosaurus and primitive birds like Archaeopteryx and Hesperornis. Paleobiology Stenonychosaurus are thought to have been predators, a view supported by its sickle claw on the foot and apparently good binocular vision. Stenonychosaurus teeth, however, are different from most other theropods. One comparative study of the feeding apparatus suggests that Stenonychosaurus could have been an omnivore. The jaws met in a broad, U-shaped symphysis similar to that of an iguana, a lizard species adapted to a plant-eating lifestyle. Additionally, the teeth of Stenonychosaurus bore large serrations, each of which is called a denticle. There are pits at the intersections of the denticles, and the points of the denticles point towards the tip, or apex, of each tooth. The teeth show wear facets on their sides. Holtz (1998) also noted that characteristics used to support