66-million-year-old feather in dinosaur poop may reveal why birds survived the asteroid

About 66 million years ago, a large dinosaur, possibly a T. rex or Nanotyrannus , swallowed a bird. Remarkably, evidence of that ancient meal survived in fossilized feces, preserving what researchers describe as the finest feather specimen yet discovered from the age of dinosaurs. By examining that feather, scientists say they may have uncovered an important clue to why birds became the only dinosaur lineage to survive the mass extinction at the end of the Cretaceous Period.

The findings were reported in Current Biology .

"It's such a beautiful, well-preserved feather, from such an unexpected source, and it's exciting that it could help us answer this huge question in paleontology," says Jingmai O'Connor, the lead author of the new paper and the associate curator of fossil reptiles at the Field Museum in Chicago.