• E-mail
• Print
• Comment
• Font Size
• Digg
• del.icio.us
• Discuss article

Prehistoric aquatic animals were not dinosaurs

Posted on: Thursday, 18 September 2003, 06:00 CDT

You wanted to know

Kristina Vazquez, 8, of Mundelein wanted to know:

Have scientists found bones or fossils from water dinosaurs?

If you have a question you'd like Kids Ink to answer, write Kids Ink, care of the Daily Herald, 50 Lakeview Parkway, Suite 104, Vernon Hills, IL 60061 or send an e-mail to lake@@dailyherald.com. Along with the question, include your name, age, phone number, hometown, grade and school.

For more information

To learn more about dinosaurs, Fremont Public Library in Mundelein suggests the following.

- "Megatooth" by Patrick O'Brien.

- "True-Life Monsters of the Prehistoric Seas" by Enid Fisher.

- "Giant Shark: Megalodon, Prehistoric Super Predator," by Caroline Arnold.

- "Supercrock and the Origin of Crocodiles" by Christopher Sloan.

On the Web

Visit the library's Web site at www.fremontlibrary.org for links to dinosaur information like the Field Museum Web site.

"Have scientists found bones or fossils from water dinosaurs?" asked Kristina Vazquez, 8, a third-grader at Diamond Lake School in Mundelein.

Peter Makovicky, curator of dinosaurs at the Field Museum, explained why dinosaurs were never aquatic or underwater animals.

"All dinosaurs, including birds, are descended from a land- living ancestor. Unlike many other groups of vertebrates, they never evolved into truly aquatic forms, although like most animals, they could probably swim reasonably well if necessary," he said.

Physical characteristics prevented the dinosaur from being a full- time swimmer. Makovicky said the hip joint was designed in such a way as to allow for faster movement on land, like walking or running.

Makovicky said, "There are no truly aquatic dinosaurs, but other large marine reptiles such as icthyosaurs, plesiosaurs and mosasaurs are known from the age of dinosaurs."

Icthyosaurs and plesiosaurs had large flippers. Some had tails like sharks and nostrils at the top of their heads. Makovicky said they share a common ancestry with modern snakes and lizards.

Mosasaurs are marine lizards related to the Komodo dragon.

"Fossils of these kinds of animals were actually discovered earlier than the first discoveries of dinosaurs, and there has been a long tradition of studying these creatures," he said.

Dinosaur fossils gave evidence to scientists that most of the extinct creatures appear to have spent their lives on dry land feeding on plants or animals. The exception is a few fish-eating dinosaurs like Suchomimus. Many dinosaurs such as Velociraptor and Protoceratops actually lived in dry desert habitats where water was scarce.

Makovicky said paleontologists - people who study prehistoric life by examining plant and animal fossils - need a broad knowledge base to accurately identify dinosaur remains.

"Discovering and excavating dinosaurs in the field is a wonderful experience, and it's what most people consider to be the heart and soul of paleontology," he said.

But there's much more involved.

"Paleontologists are trained in the sciences of geology and biology, so that they can understand the fossils they find and the environments those fossil organisms lived in," he said. "They have to know what types of rocks yield (a) particular type of fossils and what those rocks tell us about ancient environments.

"They also have to understand how modern animals function, so that they can infer how ancient animals may have functioned," he said.

Visit the Field Museum where you can see skulls of mosasaurs (85 million years old) and icthyosaurs (190 million years old) in the "Life Over Time" exhibit.

More News in this Category