Albertosaurus was an average sized tyrannosaur. These carnivores were about 26-30 feet long and weighed roughly 2 tons. Albertosaurus may be the fastest large theropod yet. Despite it's size, this tyrannosaur could run as fast as 35 miles per hour. Albertosaurus would have been one of the top predators in the area. They lived about 75 million years ago in North America.