NEW YORK (AP) — Using fossilized feces and vomit samples from Poland, scientists have reconstructed how dinosaurs came to dominate the Earth millions of years ago.

Researchers aren’t sure whether dinosaurs’ rise over the course of 30 million years happened because of luck, skill, climate or some combination. But they came away knowing this: “It was not a sudden thing,” said study co-author Martin Qvarnström from Uppsala University.

The new study, published Wednesday in the journal Nature, analyzed hundreds of dino droppings to reconstruct who was eating whom 200 million years ago.

The first dinosaurs were go-getters, Qvarnström said, eating whatever they could — including insects, fish and plants.

When climate conditions changed, they were quick to adapt. Plant-eating dinosaurs, for example, ate a greater variety of greens than other vegetarians of the time, so it was easier to expand their palates when wetter conditions gave rise to new plant species.

Since the study’s findings were limited to Polish fossils, Qvarnström said he’d like to see if their ideas hold steady against fossil records from around the world.

It’s not uncommon for scientists to study ancient fecal matter to understand creatures of the past, said Emma Dunne, a paleobiologist at the University of Erlangen-Nuremberg. But fossilized feces can resemble blobs or chunks of rock, and they are not always found near fossils of the animal that made them — which makes it hard for scientists to know where they came from.

In this study, researchers found fish scales, insect bits and bone shards nestled within the droppings.

“They are a really unassuming, quite plain part of the background,” said Dunne, who was not involved with the new research. “But they hold so much delicate, fine information.”

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