Albertosaurus (meaning "Alberta lizard") is a genus of tyrannosaurid theropod that lived in western North America during the Late Cretaceous Period, about 70 million years ago.

As a tyrannosaurid, Albertosaurus was a bipedal ( moves by means of its two rear limbs or legs) predator with tiny, two-fingered hands and a massive head that had dozens of large, sharp teeth. 
It may have been at the top of the food chain in its local ecosystem. Although relatively large for a theropod, Albertosauruswas much smaller than its more famous relative Tyrannosaurs, probably weighing less than 2 metric tons.