Dinosaur reproduction Dinosaur reproduction Dinosaur reproduction was relevant to archosaur physiology, with newborns hatching from eggs. Dinosaurs did not nurture their offspring as mammals typically do, and because dinosaurs did not nurse, it is likely that most dinosaurs were capable of surviving on their own after hatching. A discovery of features in a "Tyrannosaurus rex" skeleton provided more evidence that dinosaurs and birds evolved from a common ancestor and, for the first time, allowed paleontologists to establish the sex of a dinosaur. When laying eggs, female birds grow a special type of bone between the hard outer bone and the marrow of
Specimens of Archaeopteryx other "Archaeopteryx" specimens. The left wing preserves the better plumage and shows flight feathers firmly connected to the arms. Though the wings overlap each other enough that assigning feather attachment points to individual bone regions is not possible, it does appear, consistent with other specimens and modern relatives, that the long primary feathers are attached to the second manual digit. The feathers of the right wing are considerably more damaged; so many feathers are missing that only a few can be definitively linked to the ulna, designating them as secondary remiges. One small feather is isolated next to the right