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Eggs-Citing Discovery

When you think of dinosaurs, what do you picture? A beastly Tyrannosaurus rex pounding the ground as it chases its prey? Or a quick-moving velociraptor flashing its razor-sharp teeth as it prepares to feast? How about a herd of huge female dinosaurs making nests and keeping a watchful eye on their eggs?

That last image is probably harder to imagine than the others. That's because we know more about the hunting habits of most dinosaurs than we do about their family life. Now a discovery in South America is helping scientists learn more about dinosaur mothers and their young.

Oh, Baby!
Some 80 million years ago, a herd of long-necked females really did watch over their eggs on a riverbank in the southern part of South America. One day a flood rushed across the land. The mothers had to flee as thousands of eggs were buried under mud. The dinosaur nursery was lost forever.

Well, not quite forever. Last year a group of American and Argentinian scientists were searching for dinosaur fossils in a dry region of Argentina called Patagonia. They hadn't had much luck until they spotted a flat, barren area in the distance. As they drew near, they saw thousands of grapefruit-size rocks littering the land. They began walking around and quickly realized that the "rocks" were not rocks at all--they were fossilized dinosaur eggs! "There were thousands of eggs all over the place," says Luis Chiappe, one of the group's leaders. So many eggs, in fact, that the scientists couldn't avoid stepping on some!

They learned to be more careful, which is a good thing. Not only are the eggs themselves in amazing shape, but so are many of their precious contents: the remains of small, unborn dinosaurs. Before this discovery, only five dinosaur embryos, or unborn babies, had ever been found. Chiappe's team found dozens of them in eggs that had been broken.

Tremendous Titanosaurs
The eggs were laid by a type of dinosaur known as a sauropod--a giant, plant-eating creature with a long tail, long neck and small head. (An apatosaurus is a sauropod.) These eggs probably belonged to titanosaurs, smaller versions of sauropods that lived in the area.

Of course, "small" when it comes to sauropods is not very small at all! A full-grown titanosaur measured 50 feet from head to tail. Baby titanosaurs were about 15 inches long at birth, "the size of a small poodle," says Chiappe.

Some of the baby titanosaurs found inside the Patagonian eggs were nearly that size--and were just about to hatch. Unfortunately, they never got the chance. When the flood hit, "everything seems to have been buried quickly," says Chiappe. "The dinosaurs probably suffocated."

Prehistoric Parents
What was terrible for the dinosaurs turned out to be terrific for today's scientists. Mud slipped through cracks in the eggshells and helped preserve tiny details. One embryo had 32 pencil-shaped teeth, each small enough to fit inside this capital O. Others contained fossilized patches of scaly, lizard-like skin. "Finding dinosaur embryos is rare enough," says Chiappe. "Finding the tissue that surrounded those bones is truly spectacular."

Scientists hope the incredible discovery will answer key questions about dinosaur mothers. Already they have learned that herds of sauropods formed nesting groups. Says dinosaur scientist John Horner: "It's a survival strategy. It would have been quite a sight!"

Chiappe and his team plan to return to Patagonia in March. They hope to answer more questions, including whether the mama dinosaurs laid their eggs randomly or in carefully arranged nests. With so many eggs yet to be studied, the answers to such questions may be just inside those ancient eggshells, waiting to hatch.

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A Crocodile Dinosaur
"A dinosaur trying hard to be a crocodile" is how scientist Paul Sereno describes the 36-foot-long dinosaur that he and his team discovered in Africa's Tenere Desert. Sereno revealed his discovery last month. Scientists named the new dinosaur Suchomimus tenerensis (Sook-oh-my-muss ten-air-en-siss).

Suchomimus lived 100 million years ago and belonged to a group of fish-eating predators called spinosaurs. Its long, narrow jaw was spiked with more than 100 cone-shaped teeth. It also used foot-long claws on its thumbs to catch fish.

Sereno says his find provides the missing pieces for "what spinosaurs looked like, bone for bone." And tooth for fearsome tooth!

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