Image: A 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.

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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:
Illustration: Xiphactinus audax compared with 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.

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