When little Dee is harassed by the neighborhood hawk, Mama tells her that her 20-million-times great-great-great-grandmother was an enormous dinosaur named Granny Rex and that Granny Rex still lives in Dee's feathers and bones. It's true: Not only did birds descend from dinosaurs, but they are related to the Tyrannosaurus rex, one of the mightiest dinosaurs of all! "Never forget," says Mama to her little bird, "that you are a dinosaur." Dee discovers she might be small, but she is mighty.