Caenagnathus

Caenagnathus was a large, bird-like oviraptorosaur from the Late Cretaceous Dinosaur Park Formation in Alberta, Canada. 5 metres in length and weighing around 100 kilograms, it was among the largest known caenagnathids of its time. When first unearthed, its fused, toothless jawbone was so remarkably avian in form that palaeontologists originally classified it as an ancient bird rather than a non-avian dinosaur. Later discoveries confirmed it was a fleet-footed cursorial theropod with powerful legs, grasping three-fingered hands, and feathered wings. Caenagnathus possessed a tall head crest and deep jaws, using a keratin-covered beak to browse vegetation, process tough seeds, and occasionally capture small vertebrates.

Its toothless lower jaw was so bird-like that it was originally described as a true bird.

Where and when

Caenagnathus lived in the Late Cretaceous, from 76.5 to 74.8 million years ago (Campanian age). Its remains come from Canada, in the Dinosaur Park Formation.

The numbers

Length 2.4 m (estimates run from 2.2 to 2.5 m). Mass about 98 kg. Hip height about 1.1 m. That is 1.4 human-lengths, or 0.21 of a double-decker bus. These are estimates from partial skeleton; fields marked estimated by the site are length, mass, hip height.

Compare Caenagnathus with a bus Place on the timeline