<p>Image: A hesperornis</p>

A long, slender neck gave Hesperornis a silhouette similar to a modern-day grebe.

Copyright © MMVII NGHT, Inc.

Fast Facts

Length, up to 5 ft (1.5 m)
Did you know?
The bulk of Hesperornis fossils known are from Canada, a testament to the ancient bird's preference for cooler waters at northern latitudes.
Size relative to a 6-ft (2-m) man

Please add a "relative" entry to your dictionary.

Hesperornis was a large flightless bird that swam in the oceans and snared fish with a tooth-lined beak. Its small wings were held close in to the body and were of little use beyond possibly helping it steer through the water. Instead, Hesperornis relied on its powerful hind legs and webbed feet to chase prey and evade predators in the Cretaceous seas. A flattened tail may have helped the bird change depth and direction underwater.

In fact, Hesperornis was so adapted to diving and swimming that walking on land was an awkward proposition at best. Presumably, the bird only ventured onto solid ground to breed and lay eggs. Neither water nor land were safe for Hesperornis: Dinosaurs were terrestrial threats, and the aquatic mosasaur giant Tylosaurus was known to consider Hesperornis a tasty meal.

On the water, a long, slender neck gave Hesperornis a silhouette similar to a modern-day grebe. It probably fed and bred much like a penguin.

Prehistoric Features

  • Photo: Gully bones

    Digging Up Sea Monsters

    Follow the blog from the Spitsbergen Expedition as they unearth "sea monsters″ from the Upper Jurassic Period 150 million years ago.

  • <p>Image: A bacculite</p>

    Photo Gallery: Sea Monsters

    Get a glimpse of what prehistoric sea creatures may have looked like millions of years ago.

  • Photo: A Dimorphodon flies across the forest in a scene from the movie Flying Monsters 3D

    Flying Monsters 3D

    Could flying monsters have existed? With cutting-edge 3-D filming technology and CGI, Flying Monsters 3D recreates spectacular pterosaurs and brings these giant flying creatures to life.

  • <p>2565.jpg</p>

    Bizarre Dinosaurs

    A bizarre gallery of Mesozoic monsters prompts John Updike to ask: What has evolution wrought?

Animals A-Z

Animals A-Z