Episode 4608 - When Dinosaurs Walked Sesame Street HBO Premiere: Saturday February 27, 2016 PBS Premiere: Thursday September 15, 2016 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. This episode features an all-new street story. If you saw "When Dinosaurs Walked Sesame Street" please like this post and share your thoughts below.