Fossil evidence suggests 'feathered' dinosaurs
16 September 2011 Last updated at 07:00 BST
Samples of amber in western Canada containing feathers from dinosaurs and birds have yielded the most complete story of feather evolution ever seen.
Eleven fragments show the progression from hair-like "filaments" to doubly branched feathers of modern birds.
The analysis of the 80-million-year-old amber deposits is presented in Science magazine.
Pallab Ghosh reports.