Dinosaur Fossil Contained Rare Ancient Bird Feathers

Scientists identified bird feathers inside a 66-million-year-old dinosaur coprolite from Montana.

Updated on Sept. 18, 2026 in Life Sciences

Dinosaur Fossil Contained Rare Ancient Bird Feathers

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Researchers discovered fossilized bird feathers, fish scales, and leg bones preserved within a 66-million-year-old dinosaur coprolite. The finding, published on September 10, 2026, marks the first time hesperornithiform feathers have been recovered.

Why it matters

The specimen provides unique insights into the survival of ancient birds during the mass extinction event. Because the coprolite protected the contents from compression, the feathers retained rare three-dimensional structures unavailable in other Mesozoic fossils.

Researchers utilized micro-computed tomography to image the three-dimensional internal structures, including a rachis and medulla, which are unique to these bird feathers. The fossilized remains were sourced from a single specimen found in the Hell Creek Formation.

The players

David DeMar Jr.

He is the researcher who discovered the fossilized coprolite in the Hell Creek Formation in 2016.

Current Biology

This is a peer-reviewed scientific journal that publishes significant research across the life sciences.

The details

The coprolite, produced by a medium-sized theropod, split open naturally to reveal the feathers after being discovered in 2016. In addition to the feathers, the specimen contained leg bones from a hesperornithiform bird and scales from a gar.

The coprolite was created 66 million years ago.
David DeMar Jr. discovered the fossil in 2016.
The research findings were published in Current Biology on September 10, 2026.

The Big Picture

This discovery shifts the understanding of avian evolution by documenting the first hesperornithiform feathers in the fossil record. It provides a concrete bridge between biological structures and the survival of ancient birds during the Cretaceous-Paleogene extinction event.

The study highlights how micro-computed tomography can uncover biological remains inside coprolites that were previously thought to be devoid of significant detail. Future scanning of similar specimens could reveal additional extinct species and ecological interactions.

The takeaway

This study demonstrates that fossilized waste can be a vital repository for fragile biological structures like feathers. Researchers believe that applying advanced imaging to more coprolite specimens could yield a broader understanding of ancient avian life.