The tooth-marked bones of giant, plant-eating dinosaurs have provided a fascinating glimpse into the prehistoric feeding habits of large carnivores living in North America around 150 million years ago—an area one expert told Newsweek was “neglected.”

For a study published in the journal PeerJ Life & Environment, a team of researchers investigated bite marks left on the bones of enormous sauropod dinosaurs—such as Diplodocus and Brontosaurus—that were made by carnivorous theropod dinosaurs.

Sauropods are a group of dinosaurs that includes the largest land-dwelling animals ever to walk the Earth. These quadrupedal dinosaurs, which could grow to colossal sizes, are characterized by their very long necks, long tails, small heads and thick legs.

Theropods, meanwhile, are a hugely diverse group of dinosaurs that were primarily carnivorous and bipedal. Modern birds are descended from one lineage of small theropods, meaning they are also members of this group.

Bones with traces of bites—i.e. tooth marks—provide important evidence of the feeding choices and behaviors of long-extinct carnivorous animals.

In the case of dinosaurs, most bite traces that have been documented to date have been attributed to large Tyrannosaurs—a family of carnivorous theropods known primarily from fossils found in North America.