Albertosaurus

Albertosaurus is a theropod dinosaur that lived in Cretaceous in Alberta.

Description
Albertosaurus was closely related to Tyrannosaurus. It was also very similar to T. rex, but Albertosaurus is smaller and lighter that its more famous relative. Albertosaurus grew about 9-10 meters long, and was estimated to weigh about 1.5 tonnes.

Gorgosaurus
The genus Gorgosaurus was once believed to be the same animal as Albertosaurus. In 2003, skull studies suggested that the two were seperate genera as originally thought, but the issue is still being debated.

Discovery
The first partial specimen was discovered in 1884, but it was officially described in 1905, mentioned briefly on the last page of Henry Fairfield Osborn's description of Tyrannosaurus.

In 1910, Barnum Brown uncovered several specimens near the Red Deer River, but he could not excavate them all. In 1997 Phil Currie and his field crew returned to the site and excavated the remaining bones. The presence of several individuals together suggests that Albertosaurus was a pack hunter.

Diet
Albertosaurus was a carnivore like all tyrannosaurids.