You'll Always Remember What Your Little One Looked Like... 68 Million Years Ago. Pteranodon is one big bird! Well technically... it wasn't bird at all but it was one of the largest flying dinosaurs with a wingspan reaching over 20ft. At 24h x 36w inches, these custom posters are sure to please. Simply send us a photo of your dino-rider and get your Dinoprint in 3-5 business days.