This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: About 66 million years ago, a dinosaur—maybe a T. rex or a Nanotyrannus—ate a bird. The record of that meal, in the form of fossilized poop, has survived to today, preserving the best example of a feather ever found from the age of dinosaurs.
By studying this feather, scientists reported in a new study in the journal Current Biology, researchers have found clues that help explain why birds are the only group of dinosaurs that survived the mass extinction 66 million years ago. "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 associate curator of fossil reptiles at the Field Museum in Chicago. Birds are a specialized kind of dinosaur, and they've been around for a long time.
The earliest known bird is Archaeopteryx, from 150 million years ago, and birds continued to evolve and coexist alongside their fellow dinosaurs for nearly 100 million years. In the aftermath of Earth's collision with an asteroid 66 million years ago, nearly all the dinosaurs, including nearly all the birds, went extinct. But one group of birds, Neornithes, survived, and every living bird today is one of their descendants.
One of the biggest mysteries in paleontology is why this one small group of birds survived when all the other birds and all the other dinosaurs died out. O'Connor has spent years studying fossil birds to try to answer this question. But this is the first time she's studied feathers that were preserved inside fossilized droppings, or coprolites.
"As far as I know, no one has ever thought to look for feathers or to study feathers in coprolites, so this project was really exciting," says O'Connor. The fossil itself came to light in 2016, when David DeMar Jr., a research scientist and Hell Creek Project collections manager at the University of Washington Burke Museum and co-author of the paper, was conducting fieldwork in northeastern Montana. "I was crawling up a rocky outcrop collecting fish fossils when I came across a dark, reddish-brown nodule about half the size of a golf ball.
I picked it up and scanned its surface through my hand lens, and that's when I couldn't believe what I was seeing: a tiny fossil feather. I was cautiously optimistic about its discovery because feathers had not yet been found in the Hell Creek Formation, even after more than 150 years of prospecting," says DeMar. Back in the lab, the researchers examined the specimen's mineral composition and took CT scans of it—essentially, thousands of X-rays that are digitally stacked to reveal the contents of an object.
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