Albertosaurus sarcophagus al-BER-toh-SOR-us
"Alberta lizard"
You 1.8 m (5.9 ft) tall
Albertosaurus 9 m (29.5 ft) long
6 people holding hands
- Length
- 9 m (29.5 ft) — About 9 m long, ~2 tonnes — leaner and faster than T. rex.
- Period
- Late Cretaceous (73–70 Mya)
- Place
- North America · Alberta, Canada
- Food
- Carnivore — Hadrosaurs and ceratopsians; build suggests a more agile hunter than T. rex.
Albertosaurus was a tyrannosaur built for speed. It was smaller and lighter than Tyrannosaurus rex, with long legs suited to chasing prey across the floodplains of what is now Alberta. A famous bonebed in Dry Island contains at least 22 individuals of different ages, hinting that Albertosaurus may have lived in groups.
What we know
- Discovered in 1884 by Joseph B. Tyrrell — the museum in Alberta is named after him.
- Smaller and more lightly built than T. rex, with longer leg bones relative to body.
- Two-fingered hands like all later tyrannosaurs.
- Lived 5–10 million years before T. rex, in the same general region.
What we guess
- Whether the Dry Island bonebed represents a pack or just animals trapped together by a flood.
- Adult speed estimates range from 20 to 30 km/h — debated based on bone strength.
- Whether the smaller body meant chasing faster prey, or just less competition with bigger tyrannosaurs.