It may not be as popular as Tyrannosaurus Rex, but Albertosaurus is by far the world's best-known tyrannosaur. On the following slides, you'll discover 10 interesting facts about Canada's most famous predatory dinosaur

"Albert" may not strike you as a very fearsome name, but the fact is that Albertosaurus was discovered in Canada's Alberta province, the vast, narrow, mostly barren stretch of territory perched atop the state of Montana. This tyrannosaur shares its name with various other "Alberts," including Albertaceratops (a horned, frilled dinosaur), Albertadromeus (a pint-sized ornithopod), and the small, feathered theropod Albertonykus.

(Alberta's capital city, Edmonton, has also lent its name to a handful of dinosaurs.)

A full-grown Albertosaurus measured about 30 feet from head to tail and weighed about two tons, compared to over 40 feet long and seven or eight tons for the most famous tyrannosaur of them all, Tyrannosaurus Rex. Don't be fooled, though: while Albertosaurus looked positively stunted next to its better-known cousin, it was still a fearsome killing machine in its own right, and may have made up with speed and agility what it lacked in sheer heft (Albertosaurus, for example, was almost certainly a faster runner than T.Rex.)

Like Albertosaurus, Gorgosaurus is one of the best-attested tyrannosaurs in the fossil record, numerous specimens having been recovered from Alberta's Dinosaur Provincial Park. The trouble is that this dinosaur was named well over 100 years ago, when paleontologists had difficulty distinguishing one meat-eating dinosaur from the next, and it may wind up being demoted from genus status and classified as a species of the equally well-attested (and comparably sized) Albertosaurus.

Thanks to its profusion of fossil specimens, we know a lot about the life cycle of the average Albertosaurus. While newborn hatchlings packed on the pounds pretty quickly, this dinosaur really experienced a growth spurt in its middle teens, adding over 250 pounds of bulk every year. Assuming it survived the depredations of late Cretaceous North America, the average Albertosaurus would have reached its maximum size in its 20th year, and may have lived for ten or so years after that (given our knowledge of dinosaur life spans).

Whenever paleontologists discover multiple specimens of the same dinosaur in the same location, speculation inevitably turns to gregarious behavior. While we don't know for sure that Albertosaurus was a social animal, this seems to be a reasonable hypothesis, given what we know about smaller theropods (like the much earlier Coelophysis). It's also conceivable that Albertosaurus hunted its prey in packs--for example, perhaps juveniles stampeded panicked herds of Hypacrosaurus toward strategically located elders!

lbertosaurus lived in a rich ecosystem, well-stocked with plant-eating prey: not only hadrosaurs like Edmontosaurus and Lambeosaurus, but also numerous ceratopsian and ornithomimid, or "bird mimic," dinosaurs. Most likely, this tyrannosaur targeted juveniles and aged or sick individuals, culling them mercilessly from the herd during high-speed chases. (And like its cousin, T. Rex, Albertosaurus wouldn't have been adverse to digging into an abandoned carcass felled by another predator).

Given its venerable fossil history, you may be surprised to learn that the genus Albertosaurus comprises only one species, A. sarcophagus. However, this simple fact obscures a wealth of messy details: this tyrannosaur was once known as Deinodon, and various presumed species have been mixed up over the years with genera like Dryptosaurus and Gorgosaurus (see slide #4). (By the way, Albertosaurus was named by Henry Fairfield Osborn, the same man who gave the world T.Rex.)

In 1910, the American paleontologist Barnum Brown stumbled across what became known as the Dry Island Bonebed: a quarry in Alberta containing the remains of at least nine Albertosaurus individuals. Incredibly, the Bonebed wound up being ignored for the next 75 years, until specialists from Alberta's Royal Tyrrell Museum revisited the site and resumed excavation, turning up a dozen additional Albertosaurus specimens and over a thousand scattered bones.

Although dozens of Albertosaurus teenagers and adults have been discovered over the past century, hatchlings and juveniles are phenomenally rare. The most probable explanation for this is that the less-solid bones of newborn dinosaurs don't tend to preserve well in the fossil record, and the vast majority of deceased juveniles would have been immediately gobbled up by predators. (Of course, it may also be the case that young Albertosaurus enjoyed a very low mortality rate, and didn't perish as frequently as adults.)

ou can construct a veritable "Who's Who" of American and Canadian paleontologists from the researchers who have studied Albertosaurus over the past century. This list includes not only the previously mentioned Henry Fairfield Osborn and Barnum Brown, but also Lawrence Lambe (who lent his name to the duck-billed dinosaur Lambeosaurus), Edward Drinker Cope, and Othniel C. Marsh (the latter two being the primary antagonists in the 19th centuryBone Wars).

Albertosaurus