Albertosaurus was an earlier relative to the better-known Tyrannosaurus. Both are examples of large, late Cretaceous Tyrannosaurids, with Albertosaurus the smaller of the two. In many ways the two were similar: the head was large compared to the body, the tiny forearms had only two fingers each, and the long tail balanced the body over two powerful back legs. But the eyes of Tyrannosaurus looked forward and those of Albertosaurus looked more toward the sides. This suggests that Albertosaurus did not judge distances as well, so that when it hunted, it probably did not leap onto its prey. It was also related to the larger, more advanced Daspletosaurus, and even lived alongside it for a while.
Stealth, power and speed were its biggest assets. With its long, powerful rear legs, Albertosaurus could outrun its prey or ambush a heavy herbivore that stood alone and unprotected. The rear legs could deliver crushing blows, knocking the prey off balance. It delivered deadly wounds with its claws. The light build and long legs show that it was relatively fast and graceful. It may have been able to run 15-40 miles per hour
The head of Albertosaurus had two small, blunt horns like the comb on a chicken today. It is possible that the male had brightly colored skin covering the horns to attract the female during mating season. It would be like birds today, with the males brightly colored to attract females.
Fossil remains of Albertosaurus are common, especially teeth, which often broken when it was feeding. Several species are recognized: Albertosaurus sarcophagus and Albertosaurus Libratus are the most common. Albertosaurus lancensis has been renamed Nanotyrannus. Some paleontologists think the theropod dinosaur Alectrosaurus olseni from Mongolia is a species of Albertosaurus. If this is correct Albertosaurus lived in both North America and Asia. Albertosaurus may have hunted in packs. Albertosaurus could have hunted Albertaceratops.
Although the small flesh-eating dinosaurs were diverse and dangerous, Cretaceous Alberta was ruled by members of the family tyrannosauridae. All tyrannosaurs had hind legs that were long and powerful, with each hind foot having three toes ending in enormous claws. The two-fingered front limbs were small, not much larger than a mature human arm. The function of the front limbs is not known.Albertosaurus, the "lizard from Alberta," was among the most fearsome predators in Cretaceous Alberta. 9 meters long and 3 meters high at the hip, it is the most common of the large carnivores found here. Smaller but longer-limbed than T. rex, Albertosaurus would have been a mobile hunter. Like modern carnivores, it probably fed on the carcasses of already dead animals as well.
Albertosaurus weighed up to 3 tons yet may have been capable of attaining speeds of more than 40 mph. This fleetness, combined with obvious physical strength, would have made Albertosaurus a fierce hunter, but less than the more massive T. Rex. Albertosaurus' neck was strong and muscular, supporting a large but lightly built head. The teeth were long and recurved with saw-like edges, perfect for tearing flesh. They were not adapted for chewing, making it likely than Albertosaurus swallowed flesh in large chunks.
Albertosaurus bones were among the earliest dinosaur remains collected in Alberta. A skull found by J.B. Tyrrell in 1884 was the first important dinosaur fossil to be discovered along the Red Deer River. It was named in 1905, the same year that Alberta became a province. Since then, many Albertosaurus fossils have been discovered. the smallest documented Albertosaurus, a juvenile less than a quarter of the size of a full grown adult, was collected from Sandy Point on the South Saskatchewan River in 1986. 
J.B. Tyrrell spent most of his long career as a geologist, explorer and entrepreneur on the Canadian Shield. However, in 1884 his first field work was in Cretaceous strata along the Red Deer River where his discovery of a skull of the Tyrannosaur Albertosaurus provided a name to the paleontological museum in Drumheller.
Reconstruction of the theropod dinosaur Albertosaurusfrom Tyrrell Museum display. (Photo by BDEC (c).) Joseph Burr Tyrrell was not a paleontologist and he claimed no priority in the discovery of dinosaurs in the Red Deer River Valley. And yet, it is his name that is attached to the premier paleontological museum in North America -- the one with a major focus on Red Deer Valley dinosaurs -- the Royal Tyrrell Museum of Palaeontology in Drumheller.The scientific discovery of dinosaurs in what is now southern Saskatchewan and Alberta was made in 1874 by George Mercer Dawson, the Canadian representative on the International Boundary Commission which was charged with examining the territory along the 49th Parallel. In 1881, an unexpected decision by the Canadian Pacific syndicate changed the subsequent settlement and development patterns of the prairies. Sandford Fleming's surveyed route of the CPR main line across the West -- one to go follow the fertile valley of the North Saskatchewan through Battleford, Edmonton and then the Yellowhead Pass -- was abandoned and replaced by a new route through the arid belt 300 kilometres to the south. The future cities of Regina, Medicine Hat, Calgary and Banff owe their existence to the CPR's decision -- as did many new discoveries of dinosaurs in the Red Deer River valley..
The Geological Survey of Canada had only sketchy information about the geology and distribution of coal along this new southern route. To rectify this, Dawson who joined the Survey in 1881, was immediately sent west to investigate the geology of the Bow and Belly rivers area. He was assisted by the geologist Richard McConnell, the fossil collector Thomas Weston and by a recent arts graduate from the University of Toronto, Joseph Tyrrell. From 1881-83 Dawson's party mapped and gathered information in advance of the CPR surveyors on the plains and along the front of the mountains. They identified many coal deposits and, incidentally, located a number of fossil sites, some with dinosaurs. 
In the MediaAlbertosaurus has been a famous tyrannosaur for a long time. It was in the popular documentary Jurassic Fight Club in the episode "Biggest Killers" where it talks about the killing ability of Albertosaurus, and in the episode "River of Death", where it shows how a pack of Albertosaurus attacked a herd of Pachyrhinosaurus. It is also shown in the movie March of the Dinosaurs, where a herd of Edmontosaurus are ambushed by a pack of Albertosaurus while the hadrosaurs are heading south during the frozen winter.
Albertosaurus appeared in the final episode of Prehistoric Park.
Albertosaurus is mentioned in the tenth episode of Primeval's third series. An Albertosaurus appears in the first episode of Primeval: New World where it kills Evan Cross's wife. The theropod is depicted with horns and a missing arm.
General Information Credits to "ROMTECH" Computer CD Dinosaur Discovery
Jurassic Fight Club
March of the Dinosaurs