Dinosaur mass of adults among these dinosaurs suggest that the eggs were primarily brooded by the male, and that the young were highly precocial, similar to many modern ground-dwelling birds. Some dinosaurs are known to have used gizzard stones like modern birds. These stones are swallowed by animals to aid digestion and break down food and hard fibers once they enter the stomach. When found in association with fossils, gizzard stones are called gastroliths. The discovery that birds are a type of dinosaur showed that dinosaurs in general are not, in fact, extinct as is commonly stated. However, all non-avian dinosaurs,
The Dinosaurs! release. The Dinosaurs! The Dinosaurs!, American television miniseries produced by WHYY-TV for PBS in 1992, featuring some of the then-modern theories about dinosaurs and how they lived. It aired four episodes from November 22 to November 25, 1992. The program features the age of dinosaurs, from the appearing of the early forms like "Herrerasaurus", to the "Tyrannosaurus" and Ceratopsians of the late Cretaceous. The possibilities whether dinosaurs were active, warm-blooded animals, had parental care, and the theory that they are the ancestors to birds are featured. What caused their extinction is also discussed. Some animated depictions were made to give