Fossils found in the stomach of a 100-million-year-old sauropod reveal that these dinosaurs didn’t fully chew their food and relied on stomach microbes for digestion. 

A new study from Current Biology analyzed the fossilized abdomen of a sauropod. Within it were fossilized plants, which provided further evidence that these creatures were herbivores and barely chewed their food. 

“No genuine sauropod gut contents had ever been found anywhere before, despite sauropods being known from fossils found on every continent and despite the group being known to span at least 130 million years of time,” said lead author Stephen Poropat of Curtin University in a press release. “This finding confirms several hypotheses about the sauropod diet that had been made based on studies of their anatomy and comparisons with modern-day animals.”

Uncovering Dinosaur Cololite

Understanding a dinosaur’s diet and eating habits is key to understanding the impact they had on the ecosystem. However, there are very few cololite (gut material) fossils, especially in sauropods, according to the study. 

It has mostly been assumed that these dinosaurs were herbivores, based on their long necks, the shape of their teeth, and jaw morphology. But with this recent finding, there is evidence to back up the herbivore theory. 

In 2017, a research group from the Australian Age of Dinosaurs Museum of Natural History was excavating the fossil of a subadult Diamantinasaurus matildae, a mid-Cretaceous sauropod. The fossil had been uncovered in the Winton Formation of Queensland, Australia.

The research team began to notice a fractured rock layer, and within it, was the dinosaur’s cololite, which contained a plethora of fossilized plants. 

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A Garden Variety Diet

After analyzing the cololite, the team concluded that this dinosaur likely only slightly chewed its food before swallowing. Because of this, the dinosaur probably relied on its stomach microbiota and fermentation to aid in digestion. 

From the fossils, the research team identified conifer foliage, seed fern, and angiosperm leaves — flowering plants. This leads researchers to think that D. matildae ate a wide variety of plants and a lot of them. 

“The plants within show evidence of having been severed, possibly bitten, but have not been chewed, supporting the hypothesis of bulk feeding in sauropods,” said Poropat in the press release.

The team also identified the chemical biomarkers for angiosperms and gymnosperms, woody, seed-producing plants.

“This implies that at least some sauropods were not selective feeders, instead eating whatever plants they could reach and safely process,” Poropat added in the press release. “These findings largely corroborate past ideas regarding the enormous influence that sauropods must have had on ecosystems worldwide during the Mesozoic Era.” 

Still More to Learn 

Although it wasn’t surprising for the researchers to discover that the sauropod was a bulk eater, the angiosperms in the dinosaur’s gut were a surprise. 

“Angiosperms became approximately as diverse as conifers in Australia around 100 [million] to 95 million years ago, when this sauropod was alive,” Poropat said in the press release. “This suggests that sauropods had successfully adapted to eat flowering plants within 40 million years of the first evidence of the presence of these plants in the fossil record.”

According to the study, the findings suggest that D. matildae ate vegetation that grew both high and low before adulthood. Which makes sense, and young sauropods could only reach so high. As they grew from hatchlings, their diets would have changed to include higher-growing vegetation. 

The ability to consume an array of vegetation may have helped these dinosaurs thrive for 130 million years. Though this is an incredible find that helps us understand a little more about sauropods, Poropat did point out a few things. 

“The primary limitation of this study is that the sauropod gut contents we describe constitute a single data point. These gut contents only tell us about the last meal or several meals of a single subadult sauropod individual,” Poropat explained in the press release. 

“We don’t know if the plants preserved in our sauropod represent its typical diet or the diet of a stressed animal. We also don’t know how indicative the plants in the gut contents are of juvenile or adult sauropods, since ours is a subadult, and we don’t know how seasonality might have affected this sauropod’s diet,” Poropat concluded in the release. 

Read More: Fossilized Dinosaur Poop Helps Explain 30-Million-Year Evolutionary Gap

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A graduate of UW-Whitewater, Monica Cull wrote for several organizations, including one that focused on bees and the natural world, before coming to Discover Magazine. Her current work also appears on her travel blog and Common State Magazine. Her love of science came from watching PBS shows as a kid with her mom and spending too much time binging Doctor Who.