Dinosaur Coprolite Preserved Ancient Bird Feathers

A 66-million-year-old fossilized dropping reveals the first known hesperornithiform feathers.

Updated on Sept. 18, 2026 in Life Sciences

A close-up of a dark, fossilized coprolite displaying detailed, mineralized imprints of prehistoric bird feathers and small fish scales. — Researchers identified the first known hesperornithiform bird feathers inside a 66-million-year-old theropod coprolite, offering rare insights into ancient avian biology and diet. AI Illustration. Upload story photo >

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Researchers discovered fossilized bird feathers and fish scales inside a 66-million-year-old theropod coprolite found in 2016. Published in Current Biology on September 10, 2026, the study provides the first evidence of feathers from a hesperornithiform bird.

Why it matters

The specimen preserves three-dimensional feather structures that would have otherwise been flattened during fossilization. This discovery suggests that scanning similar coprolites could reveal new biological data regarding prehistoric bird survival and moulting patterns.

The specimen preserves three-dimensional structures including a rachis and medulla, a combination not seen in other Mesozoic feather samples. Micro-computed tomography—a 3D imaging technique using X-rays—was used to map the internal contents of the theropod coprolite.

The players

David DeMar Jr.

The researcher who identified the fossilized specimen in the Hell Creek Formation.

Current Biology

A scientific journal that publishes peer-reviewed research across all areas of biology.

The details

The coprolite, or fossilized waste, acted as a protective casing that shielded the biological material from the immense pressure of the fossilization process. Inside, researchers identified the remains of a hesperornithiform, an extinct group of aquatic birds, including leg bones and scales from a gar, a type of primitive fish. These findings offer rare insights into the diet and physiological characteristics of ancient avian species.

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

The Tech Race

Paleontologists are increasingly using non-destructive imaging to extract data from coprolites, a field previously limited by the physical risk of opening specimens. This approach extends the use of micro-computed tomography in fossil research, allowing for the study of soft tissues that were once thought to be lost to history.

This discovery validates the use of high-resolution scanning on fossilized waste to reconstruct ancient ecosystems. Future studies may apply these same imaging techniques to other archived coprolite collections to identify previously unknown species.

The takeaway

The study demonstrates that fossilized waste is a significant, yet underutilized, archive for biological preservation. Interested readers can watch for further studies using high-resolution CT scanning to analyze internal coprolite structures.