Paleontologists have uncovered a 66-million-year-old piece of fossilized dinosaur feces, known as a coprolite, in the Hell Creek Formation of northeastern Montana. This discovery, made by paleontologist David DeMar, provides critical evidence regarding the dietary habits of large theropods and the specific evolutionary traits that allowed certain bird species to survive the Cretaceous-Paleogene mass extinction event.
The Significance of Coprolites as Trace Fossils
Coprolites are classified as trace fossils, meaning they do not consist of body parts of the organism that produced them. Instead, they provide a direct record of what an animal ate. In this specific case, the coprolite was part of a larger mass likely produced by a large theropod, such as the Tyrannosaurus rex. Through CT scanning, researchers discovered that the predator had consumed a bird, and that the bird itself had previously eaten fish, as evidenced by fish scales embedded in the fossil.
Why Some Birds Survived the Mass Extinction
The fossilized remains found within the coprolite contain feathers from an extinct line of flightless waterfowl called Hesperornithiformes. While some feathers appeared similar to modern birds, CT scans revealed others that were smaller and less dense, offering poor insulation. During the Cretaceous period, global temperatures were significantly higher, with poles estimated at around 60 degrees Fahrenheit, making thick plumage unnecessary for the Hesperornithiformes.
When the massive asteroid impact occurred, it released billions of tons of aerosols and gas into the atmosphere, blocking the sun and halting photosynthesis for approximately two years. This resulted in a drastic drop in global temperatures. The Neornithes, ancestors of modern birds, survived because they had evolved denser, more insulating feathers. In contrast, the Hesperornithiformes and other ancient birds lacked this thermal protection, perishing alongside the rest of the non-avian dinosaurs.
Has any dinosaur poop been found?
Yes, coprolites are essential tools for paleontologists. They allow scientists to understand the prehistoric own dietary patterns and ecosystem interactions. This Montana discovery is among the most well-preserved examples of dinosaur coprolite containing organic material from prey species, offering a detailed look at the edible chain of the late Cretaceous period, similar to how researchers study ancient 400-million-year-old fish to understand early aquatic evolution.
What actually killed all dinosaurs?
The primary cause of the mass extinction event 66 million years ago was a massive asteroid strike. The impact produced immediate devastation through heat and force, followed by a long-term climatic shift. The resulting atmospheric clouds of sulfur and dust blocked sunlight, leading to a long-term “winter” that collapsed the food chain, killing off all non-avian dinosaurs and many other species that could not adapt to the extreme cold.
Conclusion on Avian Evolution
- Hesperornithiformes: Flightless waterfowl that perished due to poor insulation.
- Neornithes: Modern bird ancestors that evolved dense feathers for survival.
- Coprolite Evidence: Provided the first direct evidence of a large theropod eating a bird with specific feather types.
