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# A Feather Found in the Fossilised Dung of a Large Dinosaur Dating from 66 Million Years Ago
- URL: https://theparnassian.com/en/v-okamenevshem-pomiote-krupnogo-dinozavra-vozrastom-66-millionov-let-naishli-pero/
- Published: 2026-09-12T07:16:43.000Z
- Updated: 2026-10-01T05:25:12.000Z
- Author: Alexandr Radayev
- Tags: Science, Palaeontology, Nature

David DeMar of the Burke Museum at the University of Washington found the specimen in 2016 in north-eastern Montana, while collecting fossil fish. He picked up a dark reddish-brown nodule about half the size of a golf ball, examined its surface through a hand lens and saw a tiny fossil feather. DeMar notes that no feathers had previously been found in the Hell Creek Formation, although it has been studied for more than a hundred and fifty years.

In the laboratory the mineral composition of the specimen was studied and it was scanned by computed tomography. The full picture emerged only after scanning with a micro-CT scanner: every hour of data processing revealed another feather, another scale, another bone.

Inside the coprolite were found several feathers, small scales of an armoured gar, and leg bones of a bird from the group of hesperornithiforms. Since the feathers and bones lay together, the researchers concluded that the feathers belonged to the same bird. Jingmai O'Connor of the Field Museum in Chicago, the lead author of the study, explains that the hesperornithiforms were aquatic birds, ecologically similar to loons. Most of them could not fly, and used their specialised legs for diving after prey such as fish.

Birds are a branch of the dinosaurs, and after the asteroid strike 66 million years ago almost all the dinosaur lineages disappeared, including most groups of birds. One branch survived, the neornithines, from which all modern birds descend. The hesperornithiforms were close relatives of the neornithines, but belonged to a separate lineage and died out.

There is a hypothesis that the neornithines survived because many of them lived by the water, where conditions after the impact may have proved milder. The hesperornithiforms also lived in and beside the water, yet their lineage vanished all the same, so habitat alone does not account for the matter. O'Connor suggests that the difference lay in the feathers themselves and in the way the birds moulted them.

The feathers from the coprolite are the first known feathers of the hesperornithiforms, and in structure they occupy an intermediate position between the plumage of the enantiornithines, the most widespread group of Cretaceous birds, and that of modern birds. Some of the feathers look modern and waterproof, but there are also small, downy, primitive feathers, which are associated with the dinosaurs. Contour feathers are responsible for retaining heat, and after the asteroid strike an enormous quantity of dust and debris rose into the atmosphere, sunlight diminished and a sharp cooling set in, known as the impact winter. Birds with better thermal insulation stood a better chance of surviving it