Size and Weight:
One of the most ancient of all dinosaurs, Coelophysis has left a disproportionate imprint on the fossil record: thousands of Coelophysis bones have been found in the Ghost Ranch quarry of New Mexico, leading to speculation that these small, lithe, early theropods roamed the western North American plains in herds. This sleek predator also seems to have come in two varieties: "robust" (big and strong) and "gracile" (small and sleek), which paleontologists believe corresponded to males and females. (See also 10 Facts About Coelophysis.)
For years, Coelophysis was unjustly thought to be a cannibalistic dinosaur, since what were believed to be the bones of juveniles were found fossilized inside larger, adult skeletons. It now appears that these were the bones of other reptile species, and not juvenile Coelophysis, though paleontologists are still debating the evidence. By the way, Coelophysis was also characterized by its unusually large eyes (a hint that it may have hunted by night) and by its primitive wishbone, even though this dinosaur was only remotely ancestral to modern birds.