An international team of scientists have discovered new evidence of a dinosaur dining on ancient mammals.

The foot of a tiny mammal was inside the stomach of a microraptor — a small feathered dinosaur that lived during the Cretaceous some 100 million years ago in temperate forests in what is now China.

It’s the first time a piece of a mammal was discovered inside a microraptor.

“Looking at interactions between animals, that’s much easier to tell in the modern biology in living animals because we can actually go out and make those observations,” said Caleb Brown, a curator of dinosaur systematics and evolution at the Royal Tyrrell Museum of Palaeontology in Drumheller, Alta.

“Trying to make those inferences for fossils is more difficult because you don’t necessarily know exactly which animal ate which other animal, unless you have exceptional cases like this.”

This find alone will not change understanding of Cretaceous ecosystems and how they evolved, said Corwin Sullivan, a professor in the department of biological sciences at the University of Alberta, who was involved in the new discovery.

But the discovery will contribute to the accumulation of paleontological knowledge and allow to “build up a very general picture of how food webs functioned, to some degree, in the geological past, how these various species were behaving and interacting,” Sullivan said.

“It’s rare for a preserved fossil vertebrate to have any kind of gut contents, and certainly evidence of dinosaurs eating mammals is rare.