Drought uncovers dinosaur tracks in US park

A drought in Texas dried up a river flowing through Dinosaur Valley State Park, exposing tracks from giant reptiles that lived some 113 million years ago, an official said Tuesday.

Using tiny sensors to monitor migrating monarchs

Millions of monarch butterflies migrate each fall to a specific cluster of mountain peaks in central Mexico. How exactly they navigate to their winter home, and the way they choose their path, is a topic of great interest ...

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