In an evolutionary sense, birds are a living group of dinosaurs because they descended from the common ancestor of all dinosaurs. Other than birds, however, there is no scientific evidence that any dinosaurs, such as Tyrannosaurus, Velociraptor, Apatosaurus, Stegosaurus, or Triceratops, are still alive. These, and all other non-avian dinosaurs became extinct at least 65 million years ago at the end of the Cretaceous Period.
Many shared evolutionary characteristics can be found in the skeletons of birds and other dinosaurs. One can follow the development of these evolutionary innovations by following along the evolutionary tree of dinosaurs, from larger groups into successively smaller ones.