Plant-Based Dinosaurs

Were sauropods vegan?  

Researchers have long believed so but never had any proof. 

But now, fossils found in the abdomen of one of these dinosaurs have provided the evidence, according to a new study. 

It concluded that the sauropod in question, which lived about 94 to 101 million years ago, ate multiple plants and mostly relied on its gut microbes to digest them. 

Given the lack of sauropod cololites, or preserved gut contents, researchers had based their theories about their diets on anatomical features such as tooth wear, jaw morphology, and neck length. They say that discovering the diets of dinosaurs is important to understand their biology and the role they played in their ecosystems.  

“No genuine sauropod gut contents had ever been found anywhere before,” lead study author Stephen Poropat said in a statement. “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.”  

The discovery came about after the excavation of a relatively complete sub-adult skeleton of the sauropod Diamantinasaurus matildae from the mid-Cretaceous period, found in the Winton Formation of Queensland, Australia. 

There, the team found an unusual, fractured rock layer that seemed to contain the sauropod’s cololite, in which they discovered many well-preserved plant fossils.  

In the cololite, researchers found many different plants, from cone-bearing seed plants to flowering plants. The plants look to have been severed, maybe bitten, but not chewed, showing that D. matildae were likely indiscriminate, bulk feeders.  

The analysis backed that theory, showing how these dinosaurs minimally processed food in their mouth, relying instead on fermentation and gut microbes for digestion.  

This capability to bulk feed on a wide range of plants might be one reason why sauropods survived as long as they did, which was through most of the 160 million years of the dinosaur age.  

“These findings largely corroborate past ideas regarding the enormous influence that sauropods must have had on ecosystems worldwide during the Mesozoic Era,” said Poropat. 

However, this study has a limitation, namely that the cololites analyzed are a single data point.  

“These gut contents only tell us about the last meal or several meals of a single subadult sauropod individual,” said Poropat. “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.”