Gorgosaurus libratus GOR-go-SOR-us

"Fierce lizard"

Gorgosaurus silhouette
You 1.8 m (5.9 ft) tall
Gorgosaurus 9 m (29.5 ft) long
6 people holding hands
silhouette · Ivan Iofrida (CC-BY) via PhyloPic
Length
9 m (29.5 ft) — About 9 m long, ~2.5 tonnes — very similar to Albertosaurus.
Period
Late Cretaceous (77–75 Mya)
Place
North America · Alberta, Canada · Montana
Food
Carnivore — Hadrosaurs, ceratopsians, and ankylosaurs — a generalist predator.
Clade
Tyrannosauridae Dinosauria Saurischia Theropoda Coelurosauria Tyrannosauroidea

Gorgosaurus is one of the best-known tyrannosaurs because so many complete skeletons have been found. It lived a few million years before Albertosaurus in nearly the same place, and the two look so similar that scientists sometimes lump them together. A 2009 skeleton of a juvenile included gut contents — the last meal of its life, made up of the legs of two young birdlike theropods.

What we know

  • More than 20 skeletons known, ranging from juveniles to large adults.
  • Same general body plan as Albertosaurus: long legs, large head, two-fingered hands.
  • A juvenile preserved with its last meal in its gut — bones of two young oviraptorosaurs.
  • Lived in the Dinosaur Park Formation alongside Centrosaurus, Corythosaurus, Daspletosaurus.

What we guess

  • Whether Gorgosaurus and Albertosaurus are different enough to be separate genera.
  • How it shared territory with Daspletosaurus — another tyrannosaur in the same formation.
  • Whether the species changed hunting style as they grew, like some living predators do.