Anatomy: Spinosaurus was bipedal (it walked on two legs). It was about 40-50 feet long (12-15 m) and weighed 4 tons or more; it is the largest known Spinosaurid (a type of meat-eating dinosaur). It had a large head with sharp, straight, non-serrated teeth in a powerful, crocodile-like lower jaw.

The Sail: Spinosaurus' huge sail may have been used for regulating its temperature. It could collect warmth from the sun and also disperse excess body heat when in the shade. The presence of this sail as a thermo-regulatory device is evidence that Spinosaurus may have been a cold-blooded animal. The sail may also have been used for mating rituals, attracting mates. The sail may have been brightly colored, like the fins of some modern-day reptiles.

Diet: Segnosaurus was a carnivore (meat-eater) with huge teeth and powerful jaws; it ate animals, including smaller dinosaurs.

Fossils and Name: Spinosaurus was named in 1915 by paleontologist Ernst Stromer von Reichenbach, from an African fossil. Fossils have been found in Egypt and Morocco, in Africa. Very few Spinosaurus fossils have been found, and they are incomplete.

Classification: Dinosauria, Saurischia (lizard-hipped dinosaurs), Theropoda (meat-eating dinosaurs), tetanura, Spinosauroidea (dinosaurs with elongated spines on their vertebrae, from the Cretaceous period).