Science: What Killed Tyrannosaurus?

During the Cretaceous period, when mammals were still furtive, slinking creatures, the mighty dinosaur, king of the reptiles, ruled the earth. Then about 60 million years ago, the last of the dinosaurs vanished. The mammals inherited the earth and have bossed it ever since. Some geologists believe that the dinosaurs were too specialized to adapt themselves to a sudden change of climate. The trouble with the theory has always been that there is no way to prove that the climate really changed. Last week the University of Chicago's Dr. Harold Urey told a Los Angeles meeting of the American Association for...

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