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Mammals On Assignment

Mammals On Assignment

Mammals
Step into the world of writers and photographers as they tell you about the best, worst, and quirkiest places and adventures they encountered in the field.




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By Rick Gore   Photographs by Robert Clark



Once upon a time, a warm-blooded, milk-producing, fur-covered beast was born. Since then, mammals have conquered every habitat on Earth. This is their story—our story.



Get a taste of what awaits you in print from this compelling excerpt.

Deep in their bones, all mammals are related. The earliest known mammals were the morganucodontids, tiny shrew-size creatures that lived in the shadows of the dinosaurs 210 million years ago. They were one of several different mammal lineages that emerged around that time. All living mammals today, including us, descend from the one line that survived. During the next 145 million years of evolution, the dominance of dinosaurs ensured that our distant mammalian ancestors remained no larger than a cat. But when a catastrophic asteroid or comet—maybe a few comets, as some scientists are now arguing—finished off the dinosaurs 65 million years ago, mammals got the most important evolutionary opportunity they would ever have. With dinosaurs gone, mammals could exploit the planet's resources themselves. Within a few million years of the impact the fossil record shows an explosion in mammalian diversity.

How did those little creatures transform into not only the hippo and the mole rat but also today's vast panorama of mammals with fur, hooves, and fangs, as well as others that swim hairless through deep oceans—or ride, like me, in a Land Rover across this grassland?

Only humans can ask that question, or hope to answer it. We are, in a sense, the ultimate mammals. To be sure, we share defining traits with the first mammals—traits that were evolving even as the morganucodontids scrambled for food among the dinosaurs: We are warm-blooded. We have specialized jaws, whose hinges came together early in our evolution to create the ear bones that let us hear better than other animals. We have complex teeth that let us grind and chew our food so that we get more nutrition out of it. We have hair. We are superb mothers whom evolution has supplied with physical adaptations—such as breasts and placental birth—that give mammalian young an important head start. We humans are among the most recent to evolve, and we use our big mammalian brains to reason and solve problems and struggle for goals beyond our basic needs. We ask about our past and wonder what it might tell us about the future.

From scratching around in the dirt to deciphering DNA—how did we get from there to here?

Get the whole story in the pages of National Geographic magazine.


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More to Explore

In More to Explore the National Geographic magazine team shares some of its best sources and other information. Special thanks to the Research Division.

Did You Know?
Earth's plate movements are an important factor affecting mammalian evolution.  What will the world look like 250 million years from now?  Some geologists think that we are entering a phase of continental collision that will eventually result in the formation of a new single Pangean supercontinent.  By projecting current plate motions into the future, they suggest that Antarctica will collide with the southern margin of Australia, and the rock layers that contain the remains of New York City, Boston, and Washington, D.C., will lie atop high mountain ranges in 150 million years.  In 250 million years, paleoreconstructionists think, North America will collide with Africa and South America will wrap around the southern tip of Africa.  This supercontinent will have a small ocean basin trapped at its center.  To watch Earth's movements and learn more about how the world might look in the future, visit www.scotese.com/newpage13.htm.

—Nora Gallagher

Did You Know?


Related Links
Mammals of the World
www.press.jhu.edu/books/walkers_mammals_of_the_world/prep.html
View unusual and familiar mammals living around the world.

Theory and Science
www.ucmp.berkeley.edu/history/evolution.html
Explore the theory of evolution and learn about the history of evolutionary thought.

Paleoreconstructions
www.scotese.com
Discover maps and animations of continental drift and climate change on Earth.

Florida Museum of Natural History
www.flmnh.ufl.edu/
Take a virtual tour of Ice Age mammals and find out why tusks are so important.

Oklahoma Museum of Natural History
www.snomnh.ou.edu/
What did mammals from the Mesozoic, Paleozoic, and Cenozoic Eras look like?  Find out more about the time of the rise of mammals at this informative site.

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Bibliography
Benton, Michael. Vertebrate Paleontology. Blackwell Science, 2000.

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NGS Resources
Gore, Rick. "Georgian Skull Find," National Geographic (August 2002).

Lange, Karen E. "The Evolution of Dogs: Wolf to Woof," National Geographic (January 2002), 2-11.

Chadwick, Douglas H. "Evolution of Whales," National Geographic (November 2001), 64-77.

Lange, Karen E. "Meet Kenya Man," National Geographic (October 2001), 84-9.

Keyser, André. "The Dawn of Humans: New Finds in South Africa," National Geographic (May 2000), 76-83.

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