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Slender tyrannosaurid Albertosaurus walking in side view with an open mouth
Life reconstruction of Albertosaurus sarcophagus.Image credit: Connor Ashbridge, CC BY 4.0, via Wikimedia CommonsCC BY 4.0Source (opens in a new tab)

Albertosaurus sarcophagus

Pronounced al-BER-toh-SORE-us sar-KOF-ah-gus

Coelurosauria · Tyrannosauridae

A lighter-built relative of T. rex from the Late Cretaceous of Alberta, Canada. A single bonebed at Dry Island held more than two dozen individuals of all ages, which made it one of the best-studied tyrannosaurs.

  • Bipedal
  • Apex predator
  • Possible pack behavior
Compare
Period
Cretaceous· Maastrichtian
Diet
Carnivore
Length
8–9 m
Mass
1,700–3,000 kg
Location
Alberta, Canada

Quick answers

How big was Albertosaurus sarcophagus?
Albertosaurus sarcophagus was about 8–9 m long. It stood about 2.3–2.8 m tall at the hips. It weighed about 1.7–3 t. (Wikipedia: Albertosaurus 2026; Currie 2003)
When did Albertosaurus sarcophagus live?
Albertosaurus sarcophagus lived during the Late Cretaceous, about 72.1–66 million years ago. (Paleobiology Database: Albertosaurus occurrences 2026; Cohen et al. 2023)
Where have Albertosaurus sarcophagus fossils been found?
Fossils of Albertosaurus sarcophagus have been found in Horseshoe Canyon Formation (Alberta) and Canada. (Osborn 1905; Currie 2003)
What did Albertosaurus sarcophagus eat?
Albertosaurus sarcophagus was a carnivore. (Osborn 1905; Currie 2003)
Who named Albertosaurus sarcophagus, and when?
Albertosaurus sarcophagus was described by Henry Fairfield Osborn in 1905. (Osborn 1905; Paleobiology Database: Albertosaurus occurrences 2026)

On this page

Period
Cretaceous72.1–66 Ma
Diet
Carnivore
Length
8–9 m
Mass
1.7–3 t
Location
Canada
Classification
Coelurosauria · Tyrannosauridae
Described
1905, Henry Fairfield Osborn

Overview

Albertosaurus sarcophagus lived in what is now Alberta about 70 million years ago, on the coastal plains and swamps of the Horseshoe Canyon Formation. Joseph Burr Tyrrell's Geological Survey of Canada party collected its first skull in 1884 on the Red Deer River, and Henry Fairfield Osborn named it in 1905.

It was a tyrannosaurid of about 8 to 9 m, lighter built than Tyrannosaurus, with longer lower legs and feet. Currie (2003) found that albertosaurines had slightly shorter, lower skulls and longer shins, metatarsals and toes than tyrannosaurines of the same size.

At Dry Island, found by Barnum Brown in 1910 and reopened by Philip Currie in 1997, a single bonebed held the remains of more than 20 individuals. Their growth rings allowed Erickson et al. (2006) to build a "life table": young Albertosaurus survived well, and mortality rose in mid-life.

Name meaning

"Alberta lizard"; sarcophagus, Greek for "flesh-eater" (Osborn 1905).

Biology & evidence

What scientists think about how this animal lived, and how strong the evidence for each idea is.

Growth

  • Young Albertosaurus survived well, and mortality rose in mid-life.

    Evidence level: Moderate evidence

    Ages from growth rings of many individuals give a survival curve like those of long-lived birds and mammals, which also explains why juvenile fossils are rare.

    Evidence for / against · 1
    Evidence for

    • Histology · Tyrannosaur age-structure analysis

      Growth-ring ages of four tyrannosaur assemblages, including Albertosaurus, show high juvenile survival and higher mortality at mid-life and near maximum lifespan.

Social life

  • Albertosaurus lived or hunted in groups.

    Evidence level: Hypothesis

    Many individuals of all ages died at one site, which suggests they were together. The bones could also have been gathered by other causes over time.

    Evidence for / against · 1
    Evidence for

    • Specimen · Dry Island Albertosaurus bonebed

      A bonebed with the remains of about two dozen Albertosaurus of different ages.

Other

  • Albertosaurus was more lightly built than Tyrannosaurus.

    Evidence level: Strong evidence

    At the same size, albertosaurines had shorter, lower skulls and longer shins, metatarsals and toes than tyrannosaurines.

    Evidence for / against · 1
    Evidence for

    • Comparative anatomy · Tyrannosaurid allometry

      Bivariate analysis of 85 dimensions across five tyrannosaurid genera: albertosaurines are more lightly built than tyrannosaurines of the same size.

Size

Length
8–9 m

(29.5 ft)

Height
2.5 mpublished range 2.3–2.8 m

(8.2 ft)

Based on large adults (femur c. 1.0 m)

Mass
1,700–3,000 kg
Albertosaurus sarcophagus was about 9 m (29.5 ft) long, roughly 5 times the height of a 1.8 m adult human.

Timeline

Lived from about 72.1 to 66 million years ago (Ma), within the Mesozoic era (252–66 Ma).

Periods: Maastrichtian (72.1–66 Ma), Late Cretaceous (100.5–66 Ma)

Early Maastrichtian bin of the type collection in PBDB; the Horseshoe Canyon fossils are usually quoted at about 70-68 Ma (secondary).

Location

Formations

Map data: Natural Earth (public domain). Modern positions, not where the continents were then.

These are the places where fossils have been found, not the full area where the animal lived.

Ecosystem

Two Albertosaurus sarcophagus hunting Saurolophus osborni, with Struthiomimus in the foreground, in the Horseshoe Canyon Formation.Image credit: ABelov2014, CC BY 3.0, via Wikimedia CommonsCC BY 3.0Source (opens in a new tab)

Lived in: Horseshoe Canyon

73.1–68 million years ago · floodplain, coastal plain, swamp / wetland

Coastal floodplains, estuarine channels and coal swamps of Alberta near the Western Interior Seaway, with periodic marine incursions.

Classification

  1. cladeDinosauria
  2. cladeSaurischia
  3. cladeTheropoda
  4. cladeCoelurosauria
  5. superfamilyTyrannosauroidea
  6. familyTyrannosauridae
  7. subfamilyAlbertosaurinae
  8. genusAlbertosaurus
  9. speciesAlbertosaurus sarcophagus

Taxonomic status: Valid

Fossil record

Albertosaurus skeletal mount (cast) at the Royal Tyrrell Museum, Alberta.Image credit: Etemenanki3, CC BY-SA 4.0, via Wikimedia Commons (unmodified except resizing), Royal Tyrrell Museum of PalaeontologyCC BY-SA 4.0 (unmodified)Source (opens in a new tab)
Specimens
Catalog numberStatusInstitutionFound
CMN 5600HolotypeCanadian Museum of Nature (CMN)1884

What has been found

Holotype: CMN 5600

  • Preserved
  • Partial
  • Reconstructed
  • Unknown / not recorded
Region by region (table)
Skeleton regions of Holotype: CMN 5600
RegionState
SkullPartial
MandibleUnknown / not recorded
TeethUnknown / not recorded
Cervical vertebraeUnknown / not recorded
Dorsal vertebraeUnknown / not recorded
SacrumUnknown / not recorded
Caudal vertebraeUnknown / not recorded
RibsUnknown / not recorded
GastraliaUnknown / not recorded
Scapula / shoulder girdleUnknown / not recorded
HumerusUnknown / not recorded
Forearm (radius / ulna)Unknown / not recorded
Hand (manus)Unknown / not recorded
PelvisUnknown / not recorded
FemurUnknown / not recorded
Tibia / fibulaUnknown / not recorded
Foot (pes)Unknown / not recorded
Skull of Albertosaurus sarcophagus (cast of TMP 2019.000.0023) at the Royal Tyrrell Museum.Image credit: Chris Woodrich, CC BY-SA 4.0, via Wikimedia Commons (unmodified except resizing), Royal Tyrrell Museum of PalaeontologyCC BY-SA 4.0 (unmodified)Source (opens in a new tab)

All specimens

Discovery

Year described
1905
Described by
Henry Fairfield Osborn
Type specimen
CMN 5600

Discovery timeline

  1. 1884 · First material found

    Tyrrell's party collects the first Albertosaurus skull

    A partial skull is collected on the Red Deer River, Alberta.

    People: Joseph Burr Tyrrell

  2. 1905 · Formally described

    Osborn names Albertosaurus sarcophagus

    Named in the same paper that named Tyrannosaurus rex.

    People: Henry Fairfield Osborn

  3. 1910 · Specimen recovered

    Barnum Brown finds the Dry Island bonebed

    Brown collects Albertosaurus bones from a bonebed that Philip Currie reopened in 1997.

    People: Barnum Brown, Philip J. Currie

  4. 2006 · Major study

    Tyrannosaur life tables published

    Erickson and colleagues describe tyrannosaur survival patterns from growth rings.

    People: Gregory M. Erickson, Philip J. Currie

Sources

  1. (2026). Paleobiology Database: Albertosaurus occurrences. The Paleobiology Database (paleobiodb.org), data service 1.2, accessed 2026-09-23. https://paleobiodb.org/data1.2/occs/list.txt?base_name=Albertosaurus&show=coords,paleoloc,strat,loc,ref&pgm=gplates (opens in a new tab)
  2. (2026). Wikipedia: Albertosaurus. Wikipedia (English), accessed 2026-09-23. https://en.wikipedia.org/wiki/Albertosaurus (opens in a new tab)
  3. Cohen, K. M., Harper, D. A. T., Gibbard, P. L. & Car, N. (2023). International Chronostratigraphic Chart (v2023/09). International Commission on Stratigraphy. https://stratigraphy.org/ICSchart/ChronostratChart2023-09.pdf (opens in a new tab)
  4. Currie, P. J. (2003). Allometric growth in tyrannosaurids (Dinosauria: Theropoda) from the Upper Cretaceous of North America and Asia. Canadian Journal of Earth Sciences 40: 651-665. doi:10.1139/e02-083 (opens in a new tab)
  5. Erickson, G. M., Currie, P. J., Inouye, B. D. & Winn, A. A. (2006). Tyrannosaur life tables: an example of nonavian dinosaur population biology. Science 313: 213-217. doi:10.1126/science.1125721 (opens in a new tab)
  6. Osborn, H. F. (1905). Tyrannosaurus and other Cretaceous carnivorous dinosaurs. Bulletin of the American Museum of Natural History 21: 259-265. https://digitallibrary.amnh.org/handle/2246/1464 (opens in a new tab)
  7. Paul, G. S. (2016). The Princeton Field Guide to Dinosaurs (2nd edition). Princeton University Press.