The Secret to the Rise of Dinosaurs Could Be Hidden in an Unlikely Place: Their Poop

Prehistoric poop is full of secrets. Now, one of those secrets—the key to the rise and dominion of dinosaurs—might have finally been revealed. In a new study, scientists analyzed hundreds of fossilized droppings and vomit, called bromalites, to reconstruct dinosaur food webs, uncovering how they were influenced by climate and by other species’ extinction.

The research, published last week in the journal Nature, shows how dinosaurs fit into food webs over the course of 30 million years. The researchers put a special focus on dinosaurs’ first appearance in the Late Triassic and Early Jurassic, roughly 230 million to 200 million years ago.

“There has never been a study of this kind, ever,” says lead author Martin Qvarnström, a paleontologist at Uppsala University in Sweden, to Science’s Kermit Pattison. “People want to study the big skeletons and not the poop.”

Though researchers have studied how dinosaurs lived and died, many questions remain around how they initially came about and grew to dominate the world. When dinosaurs first appeared 230 million years ago, mammal-like reptiles and giant crocodile-like creatures ruled the Earth. But gradually, dinosaurs outcompeted the other species. The new research shows that dinosaurs took advantage of the environment-driven changes in food sources at the time, and as a result, they grew into larger creatures.

Bromalite is an umbrella term that includes fossilized poop (known as coprolite), fossilized vomit (regurgitalite) and fossilized contents of an animal’s digestive tract (cololite). Qvarnström and his colleagues investigated more than 500 bromalite samples collected from the Polish Basin in Central Europe that together weighed more than 220 pounds.

The team uncovered surprising diversity and remarkable preservation of the food remains in the fossilized droppings and vomit. “We found bones, teeth, fish scales, plant fragments and even tiny beetles, which give us a unique glimpse into ancient diets,” Qvarnström tells Popular Science’s Laura Baisas. Some of the insects were even preserved in 3D, with the legs and antennae intact.

Researchers used this information to trace links between prey and predators—and how these changed over time. They found that dinosaur ancestors in the Triassic were small and omnivorous, and carnivores appeared next, around 220 million years ago. Then, the herbivores evolved and produced droppings laden with ferns.

The researchers found that environmental activity of the era, such as volcanic eruptions, changed the Earth’s plants. The shifts in local climates most likely allowed herbivorous dinosaurs to grow bigger and more plentiful. By eating and digesting the new plants, these dinosaurs got the upper hand compared to other non-dinosaur species. Then, in turn, the meat-eating dinosaurs that hunted them ballooned in size.

This new, comprehensive picture of the Triassic and Jurassic periods combines information from the dino poop with climate data, along with details from other fossils, including plants, footprints and bones. All the material was collected over 25 years. The final result was a much deeper understanding of dinosaurs’ dietary diversity and adaptability—both crucial traits for survival.

The study demonstrates that dinosaurs’ bromalites, though often overlooked or maligned by researchers, reveal details about how the reptiles lived and fit into ecosystems. “Inside these coprolites is a story about life and the biology of these early dinosaurs,” says study co-author Grzegorz Niedźwiedzki, a paleontologist at Uppsala University, to the Washington Post’s Carolyn Johnson.

The study is “an impressive piece of work,” says Suresh Singh, a researcher at the University of Bristol in England, to Nature News’ Helena Kudiabor. This is the first time he’s seen a study of bromalites at such a large scale, and he adds that future research could also focus on how dinosaurs evolved in different parts of the world.

With new work like this, bromalites may be improving their reputation. Qvarnström hopes the study inspires researchers to look into fossilized droppings in other regions, per Science. “People don’t really take them seriously scientifically,” he tells the outlet, “but I think that is about to change.”

Alexa Robles-Gil | | READ MORE

Alexa Robles-Gil is a bilingual science journalist based in New York City. Her work has appeared in the Guardian, Undark, Inside Climate News and more.