Ask a paleontologist.

Discoveries of fossil eggs show that dinsoaurs brooded their young.

Rare dinosaur "mummies" preserve dinosaur skin.

Fossil bones from T. rex and others reveal battle scars.

Trackways provide important clues.

Some of the best evidence comes from T. rex.

Scientists find colored, feathered dinosaur fossils.

Scientists examine the bones of dinosaurs for clues.

An asteroid impact might have played a role.

The challenges scientists face in cloning DNA.