What is the main idea of the passage?
Dr. Paul Sereno digs dinosaur bones. He gets a thrill when he digs up the bones of dinosaurs that lived millions of years ago. In 1997, Dr. Sereno led a dig in Niger, Africa. He took 18 scientists with him. The Touareg tribe helped his team look for bones. The Touareg people live in Niger. They 5 know their desert land best. They know where to look for bones.