This bull Brachiosaurus altithorax is singing a mating song through an inflatable sac attached to its nostril. The inspiration for this artwork came from a trailer for the documentary Prehistoric Planet which featured sauropods with similar sacs running down the bottom of their necks. I felt that, if sauropods had such sacs at all, they would be attached to the nostrils (and therefore connected to the dinosaur’s vocalization and respiratory systems) rather than the skin of the neck. In either case, it would be a speculative possibility rather than confirmed by paleontological data thus far.