Weirdest dinosaurs (2010)

While dinosaurs may have been some of the mightiest creatures ever to have walked the earth, they also could have been among the most bizarre. With extreme, exaggerated body parts, some predators were loaded with outlandish or disproportionately sized appendages. Join world-renowned paleontologists and travel the globe to unearth some of the lesser-known but most surprising members of the dinosaur family: Mamenchisaurus, whose neck alone was longer than the rest of its body; Chasmosaurus, adorned with a fashionable crown of frilly spikes to attract the eyes of potential suitors; Spinosaurus, with massive extensions from its vertebrae that could have supported a sail or a hump; and Parasaurolophus, whose tube-like head crest may look odd to us, but was a mating magnet back in the day. Why did these animals ever adopt such strange appendages? What was their purpose - and why did these evolutionary changes die out?