Overview: Elmo, Chris, and their friends on Sesame Street have dressed up as dinosaurs. With help from Elmo's book, they learn that there are small and big dinosaurs, some dinosaurs are herbivores and some are carnivores and that Big Bird is a dinosaur! Also featuring Jurassic Cookie parody, and Elmo's World-dinosaurs. Brought to you by the letter D and the number 15.