Stock Photo - Spinosaurus (meaning 'spine lizard') was arguably the largest known meat-eating dinosaur ... . It was longer even than Tyrannosaurus and Giganotosaurus at, according to one estimate, up to 18m in length. Named for the elongated spinal bones that make up the curious sail on its back, spinosaurus was probably a fish-eater. Its head was narrow like that of a crocodile and, like that animal, might have spent its life on land and in water. It lived towards the end of the Cretaceous period, in what is now northern Africa.