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.
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