Albertosaurus

Albertosaurus was a slender, fleet-footed tyrannosaurid that lived in western North America during the early Maastrichtian stage of the Late Cretaceous. First found along the Red Deer River in Alberta, Canada, this apex carnivore reached about eight to nine metres in length and weighed roughly two tonnes. Albertosaurus is characterised by long, gracile hind limbs, small two-fingered forelimbs, and prominent lacrimal crests above the eyes. The remarkable discovery of a mass death assemblage containing individuals of various ages strongly suggests that Albertosaurus may have lived or travelled in social groups.

A bonebed in Dry Island Buffalo Jump contains over twenty individuals, suggesting group living.

Where and when

Albertosaurus lived in the Late Cretaceous, from 71 to 68 million years ago (Maastrichtian age). Its remains come from Canada, in the Horseshoe Canyon Formation.

The numbers

Length 8.8 m (estimates run from 8 to 9.5 m). Mass about 2.1 t. Hip height about 2.8 m. That is 5.2 human-lengths, or 0.79 of a double-decker bus. These are estimates from near-complete skeleton; fields marked estimated by the site are length, mass, hip height.

Compare Albertosaurus with a bus Place on the timeline