An Ultimate Guide to Albertosaurus: The Lizard of Alberta

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Name Meaning“Alberta Lizard “Height3.4 meters (11 ft.)
PronunciationAl-bur-tuh-saw-ruhsLength8 to 9 meters (26 to 30 ft.)
EraMesozoicLate CretaceousWeight1315 to 2495 kgs. (2,900 to 5,500 lbs.)
ClassificationDinosauria, Saurischia & TheropodaLocationNorth America (Canada)

Albertosaurus Pictures

Albertosaurus roaring | Warpaintcobra via Getty Images

The Albertosaurus

Gage Beasley Prehistoric's Albertosaurus Concept
Gage Beasley Prehistoric’s Albertosaurus Concept

The Albertosaurus is a dinosaur that inhabited North America during the Late Cretaceous period, around 71 million years ago.

This dinosaur was a theropod, and a member of the dominant Tyrannosauridae family.

While a relative of the notorious Tyrannosaurus Rex, the Albertosaurus was a slighter smaller, and more agile predator. 

Since their discovery in the late 1800s, there have been way more than 30 fossil specimens of the dinosaur discovered, which all have been helpful in learning about the genus, and their relatives. 

Albertosaurus roaring | Warpaintcobra via Getty Images

This prehistoric dinosaur lived in what is now Alberta Canada, and the Horseshoe Canyon Formation is where this dinosaur has been found in abundance. 

The various fossils discovered of Albertosaurus have varied in their age and completeness.

Here you will learn about the amazing theropod, and how this Tryannosaurid interacted with its prehistoric environment. 

Paleontologists have been studying this dinosaur for over a decade, and there has been plenty learned about the ancient “Alberta Lizard”.

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Gage Beasley’s Prehistoric Shirt Collection
Gage Beasley's Prehistoric Plush Collection
Gage Beasley’s Prehistoric Plush Collection

Physical Characteristics

Gage Beasley Prehistoric's Albertosaurus Size Comparison Chart
Gage Beasley Prehistoric’s Albertosaurus Size Comparison Chart

Similar to other theropods, the Albertosaurus had a large bulky head, small arms, and carried all its weight on their back legs.

It had a length measured at 8 to 9 meters (26 to 30 ft.), and they had a long and heavy tail which helped them maintain balance when moving. 

This dinosaur was around 3.4 meters (11 ft.) tall, and weighed around 1,700 to 2,500 kgs (3,700 to 5,500 lbs).

The skull of Albertosaurus was massive, and had a length of 1 meter (3.3 feet), sitting on their short s-shaped neck.

The large and open skull had places for sensory organs, and overall they had 58 large curved teeth in their mouths. 

Albertosaurus had very short arms similar to other theropods, with 2 clawed fingers. 

Life restoration of the Albertosaurus | Nobu Tamura via Spinops

Each of the feet of this dinosaur had four clawed toes, and they had very robust legs used to support their large size. 

The Albertosaurus‘ large size, strength, and massive teeth made them super predators, but they were still smaller than some other theropods like the Tyrannosaurus Rex.

It had a slender and smaller build, when compared to the massive Tyrannosaurus Rex, who had a length between 3.6 to 6 meters (12 to 20 ft.), and weighed between 5,000 to 7,000 kgs (11,000 to 15,000 lbs).

Habitat and Distribution

The Albertosaurus inhabited North America in what is now Alberta Canada during the Cretaceous period around 68 to 70 million years ago.

The Horseshoe Canyon Formation in Alberta Canada is where the fossils from this dinosaur have been discovered, and has also helped paleontologists learn more about the habitat this dinosaur lived in.

In the Cretaceous period in North America the Western Interior Seaway split the continent, and also made the region very wet.

The regions in North America in the Cretaceous period had lots of coastal, and wetland habitats like lagoons, estuaries, tidal flats, and swamps.

The Red Deer River near Drumheller, Alberta. Almost three-quarters of all Albertosaurus remains have been discovered alongside the river, in outcrops like the ones on either side of this picture | Enzenberger via Wikipedia (CC BY-SA 3.0)

The habitat Albertosaurus lived in was a mixed woodland environment and very wet. 

Foliage that has been discovered in Cretaceous North America include ferns, conifers, and angiosperms.

While the majority of Albertosaurus fossils have been found in Canada, there have been several other discoveries across North America including New Mexico, Alaska, Montana, Wyoming, and as far south as Baja California. 

Tyrannosaurids have only been found in North America and Asia, and these dinosaurs were the most dominant predator in their environment. 

Behavior and Diet

Two Albertosaurus hunting Saurolophus | ABelov2014 via Deviant Art

The Albertosaurus was a dominant carnivorous predator, and preyed on herbivore dinosaurs they could overpower.

Slow-moving dinosaurs like the Hadrosaurus are likely what the it ate most. 

To increase their hunting success rate these dinosaurs would have also targeted young and older specimens. 

There is some evidence that has been found suggesting the Albertosaurus hunted, and lived together in packs.

Gregarious behavior was a trait that was typically seen in herbivorous dinosaurs, and there has been little evidence of group living within carnivorous dinosaurs.

Albertosaurus mother dinosaur brings her offspring a ceratops for dinner during the Cretaceous Period | CoreyFord via Getty Images

The Dry Island bonebed found by Barnum Brown is evidence that they lived in groups, and it was around 26 Albertosaurus found together fossilized. 

The dinosaurs in the Dry Island bone bed were aged from adults to very young juveniles, and some paleontologists believe this suggests the Albertosaurus lived in packs.

Younger juveniles had a sleeker build, and being faster than the older individual the young dinosaurs could have helped drive prey towards larger dinosaurs so they could take them out.

The fossil evidence supporting the pack behavior still needs research, as the dinosaurs could have fossilized together due to natural causes like flooding or other disasters. 

Figuring out if Albertosaurus lived in packs is difficult, but hunting together would have made Tyrannosaurids much more deadly hunters.

Life Cycle

Skull cast at the Geological Museum in Copenhagen | FunkMonk via Wikipedia (CC BY-SA 3.0)

Compared to other dinosaurs the Albertosaurus has had a plethora of fossil evidence from specimens of all ages, but still lacks lots of fossils from juveniles.

Fossilization bias is one of the main reasons why younger specimens of dinosaurs are very rare, and the smaller bones of juveniles are harder to fossilize.

The oldest Albertosaurus dates to around 28 years of age, and most known specimens are around 14 years old.

Bone histology is how the age of fossil specimens are known, and the youngest to be discovered was only around 2 years old, and at the time would have weighed around 50 kgs (110 lbs).

Cast in the Rocky Mountain Dinosaur Resource Center in Woodland Park, Colorado | MCDinosaurhunter via Wikipedia (CC BY-SA 3.0)

Looking at fossils, Albertosaurus is believed to have the most growth from ages 4 to 16 years old, growing around 122 kgs (269 lbs.) per year during this period. 

It had a similar growth rate to other similar Tyrannosaurids of similar size, but dinosaurs like Tyrannosaurus rex grew around 5 times the rate.

The older an Albertosaurus got, the less likely it was for them to die, but in adulthood their mortality rate increased again when fully grown.

There is still lots to learn about its life cycle like how they mated, but the large amount of fossils from these dinosaurs have allowed a more in-depth study into this genus. 

Evolution and History

Holotype specimen CMN 5600 | Joseph Tyrrell via Royal Tyrrell Museum

It was discovered in 1884, and their type specimen was a partial skull pulled out of Horseshoe Canyon Formation in Alberta Canada.

Today Albertosaurus sarcophagus is the only species.

Albertosaurus translates to the “Alberta Lizard” and their species name translates to “flesh eating” in Greek.

In 1913 a fossil found in Dinosaur Park Formation was found by paleontologist Charles H. Sternberg was named Gorgosaurus libratus, but now is considered a synonym to Albertosaurus. 

The only species accepted today is Albertosaurus sarcophagus, but there have been a few synonyms, and other species named in the past that are not valid today.

Gorgosaurus, which was described as a second species of Albertosaurus, A. libratus by Dale Russell. | Etemenanki3 via Wikipedia (CC BY-SA 4.0)

The Horse Shoe Canyon Formation has produced the most Albertosaurus fossils, and these specimens of young and old have been the most important in learning about this dinosaur. 

It is classified as a member of the Tyrannosauridae family, which were the most successful dinosaurs to live in North America. 

Tyrannosaurids evolved to have excellent binocular vision, similar to hawks, and evolved to have superior senses to make them adept hunters. 

Albertosaurus was a medium-sized Tyrannosaurid, but still larger than most other dinosaurs of its time

Their size, intelligence, and body equipped for hunting is why these dinosaurs ruled the Cretaceous period.

Interactions with Other Species

Restoration of Edmontosaurus fighting off Albertosaurus | Durbed via Deviant Art

In the formations where Albertosaurus was discovered there have been several other specimens that help show what other life lived alongside this ancient predator. 

Hadrosaurs, ceratopsians, and the ankylosaurus are some of the herbivores that lived with this dinosaur, and it likely preyed on them. 

In its time Albertosaurus was the apex predator, and was the largest dinosaur of its time period.

Bronze sculptures of a pack, RTM, designed by Brian Cooley | Willem van Valkenburg via Flickr

Dinosaurs like the T-Rex are thought to have come a few million years after Albertosaurus.

Even young Albertosaurus were likely larger than most dinosaurs they came across, and if these dinosaurs lived in packs they would be even more deadly than previously thought. 

Albertosaurus used their large size to take down prey, and as they matured filled various different roles in their ecosystem.

Cultural Significance

Skeletal cast of Albertosaurus sarcophagus on display at the Milwaukee Public Museum | WehaveaTrex via Wikipedia (CC BY-SA 4.0)

Alberta Canada is the country’s most known fossil grounds, and it is due to dinosaurs like the Albertosaurus

In Canada Albertosaurus was the first carnivorous dinosaur to be discovered, and has been a studied genus for over 100 years.

First found in 1884, this dinosaur was one of the first specimens discovered that was nearly complete.

It is a member of the Tryannosauridae family, which is one of the most popular dinosaur families, but this genus is also one of the most popular members.

It is easy for dinosaurs to get outshone by larger species, but Albertosaurus is very popular due to how abundant and complete the fossil evidence is of them.

Albertosaurus in Jurassic Park: Trespasser | Photo via Jurassic Park Wiki

In paleontology Albertosaurus has been important in learning about gregarious behaviors in carnivorous dinosaurs, and the growth rate of Tyrannosaurids. 

These dinosaurs have been popular in some of the various Jurassic Park games, and are on display in several museums. 

Dinosaurs like Albertosaurus are not only very intriguing, but are essential in learning about the traits of species that have much less fossils.


If Canada had a national dinosaur there would be no doubt the Albertosaurus would take that role, as this ancient predator is one of the country’s most well-studied, and abundant dinosaurs.

During the Late Cretaceous period, it dominated North America with the other Tyrannosaurids.

The majority of these dinosaur fossils have been discovered in Alberta Canada, but their dominance stretched across as far south as Baja California.

Dinosaurs that have lots of fossil specimens like Albertosaurus are essential in paleontology, as most dinosaurs are only known from incomplete specimens.

With the large portions of Albertosaurus fossils found, and how complete many specimens were these dinosaurs helped further research into Tyrannosaurids, and the various ways these super predators evolved. 

It is fast, fierce, and we’re one of the most abundant dinosaurs in their time period. 

Even with the amount of fossils found of Albertosaurus there is still plenty to learn about this ancient species, and how they interacted with their prehistoric environment. 

There have been more than 1,000 Albertosaurus bones uncovered, and likely many ready to be found.

Canada has had a variety of life that lived in the region, and today only the fossils and descendants remain from the animal that lived millions of years ago.


How fast was the Albertosaurus?

Using the fossils found of Albertosaurus, scientists estimate this dinosaur had a walking speed of around 14 to 21 kph (8 to 13 mph), and a top speed estimated between 30 to 40 kph (18.6 to 24 mph.)

Younger juveniles were much quicker than the bulkier adults, and while not the fastest dinosaur, it was quick enough to take down a myriad of prey.

Did Albertosaurus have feathers? 

While there has been some evidence of dinosaurs having feathers, there has been none showing that the Albertosaurus had any feathers.

There have been skin impressions left from the Albertosaurus showing they had scaly skin.

Some paleontologists think that all dinosaurs had feathers, but further evidence is needed in fossils to confirm feathers in the Tyrannosaurid dinosaurs.

Is the Albertosaurus a common fossil?

The Albertosaurus is one of the most common and abundant fossils from the Cretaceous period.

In the Dry Island bone bed in Alberta Canada there have been around 1,128 Albertosaurus bones found, which is the highest number of remains discovered of any known theropod from the Cretaceous period. 

The high number of these dinosaur fossils suggest they were very common, and dominant in their environment. 


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