National Geographic Society

Xiphactinus Audax

Xiphactinus Audax

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.

Fast Facts

Type:: Prehistoric
Diet:: Carnivore
Size:: Length, up to 17 ft (5 m)
Protection status:: Extinct
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.
Size relative to a bus:

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.

Other Prehistoric Animals

Prehistoric Features

Bizarre Dinosaurs

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

National Geographic's interactive time line takes you on a 4.5-billion-year-old trip through Earth's history⎯from its Precambrian birth to the birth of Homo sapiens some 190,000 years ago.
Prehistoric World

Discover and explore prehistoric times with galleries, time lines, quizzes, and more.
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.
Photo Gallery: Permian Period

Peer into the flourishing world of the Permian, when a wealth of new animals appeared⎯before nearly all life on Earth was wiped out in a mass extinction.

Quizzes

In the Field

See All National Geographic Projects »

This requires the latest version of Flash Player. Click here to download.

Special Ad Section

Audio Slideshow

Take a photographic journey through Montana and hear Annie Griffiths Belt's narrative.
Adventure Videos

Check out adventure videos and go "Behind the Lens."

Shop Animals and Nature

Animal & Nature DVDs

Shop our store for a wide collection of animal, wildlife, and nature DVDs.
2010 Animal & Nature Calendars

Featuring stunning National Geographic photography, calendars make great gifts.

Blogs

NatGeo NewsWatch

Keep current on developments in science, nature, and cultures.
Dog Whisperer

Get the inside story as Cesar Millan helps problem dogs and their owners.
BlogWild

National Geographic explorers share tales (and photos) of their adventures.