Question 1

How do you say Xiphactinus?

Accepted Answer

Xiphactinus is pronounced zy-FAK-tin-us. The tricky part is that opening X, which is pronounced like a Z because the name comes from the Ancient Greek word 'xiphos' meaning sword. Break it down as zy, then FAK, then tin, then us. Say it a few times fast and it starts to feel natural. Once you know the Z trick, you will never mispronounce it again.

Question 2

What does Xiphactinus mean?

Accepted Answer

The name Xiphactinus combines two Ancient Greek words: 'xiphos' meaning sword, and 'aktinos' meaning ray or beam. So it roughly translates to sword ray fish or sword-rayed fish. Paleontologist Joseph Leidy chose this name in 1870 to describe the long, sharp, sword-like teeth that jut from the front of its jaws. Those fang-like front teeth are one of the most immediately striking features of the skull and inspired the name perfectly.

Question 3

How big was Xiphactinus?

Accepted Answer

Xiphactinus could grow up to 20 feet long, which is roughly the length of a full-sized SUV, and it may have weighed over 1,000 pounds. That makes it one of the largest predatory bony fish ever to have lived. For comparison, a giant barracuda today reaches about 6 feet, so Xiphactinus was more than three times the length of the biggest barracuda alive. Its massive size put it near the top of the food chain in the Western Interior Seaway.

Question 4

What did Xiphactinus eat?

Accepted Answer

Xiphactinus was a ferocious predator that ate large fish, squid, and likely anything else it could fit in its enormous jaws. We know this partly because of an incredible fossil discovered in 1952 that showed a nearly 6-foot-long fish called Gillicus preserved whole inside a Xiphactinus stomach. Scientists believe Xiphactinus used its upturned jaws and fang-like front teeth to snatch and swallow prey whole or in large chunks. Its large size meant it could target prey that most other fish would have ignored.

Question 5

Was Xiphactinus a dinosaur?

Accepted Answer

No, Xiphactinus was not a dinosaur at all. It was a fish, specifically a large predatory bony fish that lived in the ocean while dinosaurs walked the land. Dinosaurs, by scientific definition, are land-dwelling animals in a specific evolutionary group, while Xiphactinus belonged to the Ichthyodectiformes, an extinct order of marine ray-finned fish. The two did live at the same time during the Late Cretaceous period, so while a T. rex was hunting on shore, a Xiphactinus was hunting in the sea a few miles away.

Question 6

Where did Xiphactinus live?

Accepted Answer

Xiphactinus lived primarily in the Western Interior Seaway, a warm shallow sea that once flooded the middle of North America from the Gulf of Mexico up through Kansas, Nebraska, and into Canada. Fossils have been found in the United States and Canada, but also in Germany, suggesting that similar seas in Europe were also home to this fish. The chalk rock formations of western Kansas, especially the Niobrara Formation, have produced the most complete and spectacular Xiphactinus specimens ever found.

Question 7

Did Xiphactinus die out with the dinosaurs?

Accepted Answer

Yes, Xiphactinus went extinct at the end of the Cretaceous period about 66 million years ago, the same mass extinction event that wiped out the non-avian dinosaurs. This event, most likely caused by a massive asteroid impact combined with intense volcanic activity, collapsed marine food chains around the world. Xiphactinus had actually been around for a very long time before its extinction, first appearing roughly 119 million years ago, which means it survived for over 50 million years before finally disappearing.

Question 8

What is the Fish Within a Fish fossil?

Accepted Answer

The Fish Within a Fish is one of the most famous fossils in the world and it involves Xiphactinus. In 1952, fossil hunter Charles H. Sternberg excavated a 14-foot Xiphactinus specimen in Logan County, Kansas, and found a nearly complete 6-foot fish called Gillicus arcuatus perfectly preserved inside the Xiphactinus stomach. The smaller fish was so intact that scientists believe the Xiphactinus died very soon after swallowing it, possibly because the struggling prey caused fatal internal damage. The specimen is now displayed at the Sternberg Museum of Natural History in Hays, Kansas, and it remains one of the most dramatic fossil discoveries ever made.

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