Picture of Xiphactinus

Xiphactinus was a fast, strong swimmer and may have leapt from waters to dislodge parasites from its skin. It is also possible that there were lots of little fish that swarmed around it, nibbling on parasites, much the same as they do today for larger fish.

Copyright © MMVII NGHT, Inc.

Fast Facts

Type:
Prehistoric
Diet:
Carnivore
Size:
Length, up to 17 ft (5 m)
Did you know?
A Xiphactinus on display at a museum in Kansas has a complete, well-preserved fish inside it. Scientists believe the struggling prey ruptured an organ of its captor as it was swallowed, killing the larger fish.
Relative:
Size relative to a bus

Please add a "relative" entry to your dictionary.

Xiphactinus was one of the largest bony fish of the Late Cretaceous and is considered one of the fiercest creatures in the sea. A powerful tail and winglike pectoral fins shot the 17-foot-long (5-meter-long) monster through the surface waters of the ocean. Unlucky fish and unsuspecting seabirds were snared inside Xiphactinus's upturned jaw, which was lined with giant, fanglike teeth, giving it an expression akin to that of a bulldog.

A 13-foot-long (4-meter-long) Xiphactinus could open its jaw wide enough to swallow six-foot-long (two-meter-long) fish whole, but it itself was occasionally prey to the shark Cretoxyrhina.

Xiphactinus trolled an ancient ocean called the Western Interior Seaway, which covered much of central North America during the Cretaceous. Though long extinct, if alive today the bony fish would look like a giant, fanged tarpon.

Prehistoric Features

  • Picture of carnotaurus

    Bizarre Dinosaurs

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

  • Picture of dimorphodon flying 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.

  • Picture of dinosaurs during the Jurassic era

    Prehistoric World

    Discover and explore prehistoric times with galleries, time lines, quizzes, and more.

  • Picture of a theoretical scene of the mass extinction of dinosaurs

    Mass Extinctions

    More than 90 percent of all organisms that have ever lived on Earth are extinct. Learn how millions of creatures can disappear in a geological blink of an eye—and see what might be next.


Animals A-Z