The Albertosaurus was a meat-eating dinosaur that lived 75 million years ago in what is now North America, during the Late Cretaceous Period. Although not quite as big (or famous) as its closest relative Tyrannosaurus Rex, Albertosaurus was a fierce predator and an effective killing machine in its own right.
Albertosaurus was named after Alberta, Canada, where the dinosaur’s bones were first discovered. In fact, Albertosaurus got its name in 1905, the same year Alberta became an official Canadian province. Albertosaurus has even appeared on at least one Canadian postage stamp. Although first discovered in Canada, Albertosaurus fossils have been found as far south as Southern California.
Like T-Rex, Albertosaurus was bipedal, meaning it walked on two feet. Its back legs were well developed and extremely muscular—capped with razor-sharp claws. The back legs could deliver fatal blows to prey and propel Albertosaurus to speeds up to 30 miles per hour. In contrast, Albertosaurus’s front legs were short and not well muscled.
Albertosaurus belongs to a group of dinosaurs called “theropods.” The word ‘theropod’ means, literally, "beast-footed" and paleontologists use the term to refer to all carnivorous dinosaurs.
Albertosaurus grew to between 26 and 30 feet long and probably weighed around three tons (6,000 pounds). It was approximately 15 feet high. Compare this to the T-Rex, which grew up to 40 feet long, was between 15-20 feet tall, and weighed five-seven tons (10,000 to 14,000 pounds).
Several Albertosaurus fossils suggest that they may have bitten each other during fighting. For example, scientists have determined that gouges in the jaw of a fossil referred to as TMP 2003.45.64, are likely the result of injuries sustained when dinosaurs would bite each other on the face during altercations.
Notwithstanding apparently violent altercations, many scientists believe that Albertosaurus may have lived, or at least hunted, in packs. One of the main bases for this conclusion is the discovery of several Albertosaurus fossils on Aug. 10, 1910, by Barnum Brown and Peter Kaisen, near what is now Dry Island Buffalo Jump Provincial Park in Alberta. The bones they discovered came from at least seven separate individual dinosaurs.
In a 1998 paper titled "Possible Evidence of Gregarious Behavior in Tyrannosaurids," Philip Currie, a Professor of Dinosaur Paleobiology at the University of Alberta, observed that “the almost complete lack of bones of herbivorous dinosaurs, and the absence of tooth marks or other evidence of predation suggests that the site was probably not a predator trap.” Currie further explained that the dinosaurs at the site appeared to have all died around the same time, and reasoned that “because it is difficult to imagine why they would have collected into a group immediately before death, they were probably living together before they died.” According to Currie, pack hunting behavior would have increased the Albertosaurus’s chances for survival, since it would have made it easier to bring down one large plant-eating dinosaur.
The possible pack behavior of the Albertosaurus is the subject of an exciting display at the Royal Tyrrell Museum in Alberta. The exhibit features four Albertosaurus moving across a dry riverbed, and is based upon the "bonebed" discovered at Dry Island Buffalo Jump Park.
Albertosaurus are now the most commonly uncovered dinosaur fossil in Alberta. Perhaps a future discovery will give more information on these creatures and solve the mystery of whether or not they really lived in packs.