With movable lower jaw. This dangerous carnivore weighed several tons and could be up to 17 meters long. The Spinosaurus had many sharp, straight teeth in a crocodile-like mouth. His meals consisted mostly of other dinosaurs or fish. The intelligently designed sail on his back fulfilled several functions. It probably contributed to the vital regulation of temperature in cold-blooded dinosaurs by collecting or distributing heat. It also served to impress potential sexual partners.