Rosalind Evans
A remarkable fossil, dating back 125 million years to the Cretaceous Period, has provided a glimpse into an extraordinary encounter between a small mammal and a dinosaur. The fossil, found in northeastern China, captures the scene of a badger-like mammal called Repenomamus robustus and a plant-eating dinosaur known as Psittacosaurus engaged in mortal combat.
This discovery challenges the prevailing notion that early mammals lived in the shadows of dinosaurs, as it showcases a mammal of considerable size standing up against a dinosaur three times its size. Dr. Jordan Mallon, a paleobiologist from the Canadian Museum of Nature and coauthor of the study published in Scientific Reports, emphasizes that this fossil overturns the belief that larger dinosaurs solely preyed on smaller mammals. Instead, it suggests that these mammals were capable of taking down larger dinosaurs if circumstances demanded it.
Although previous evidence has indicated that early mammals preyed on dinosaurs, this particular fossil is exceptional in its depiction of the mammal actively attacking the almost fully grown dinosaur. Fossils that capture interactions between animals are incredibly rare, shedding light on the predatory behavior of extinct creatures. Renowned specimens such as the dueling dinosaurs, featuring a Triceratops horridus and a Tyrannosaurus rex locked in battle, exemplify the rarity of such findings.
The Psittacosaurus, a small beaked dinosaur resembling today’s sheep, was a common species in the region during that time. The predator and prey in this case were both nearly fully grown when the attack occurred.
Dr. Mallon expresses his excitement at studying this fossil, which was discovered in 2012 at China’s Lujiatun fossil beds in the Liaoning province—a site comparable to Pompeii for paleontologists. Both skeletons are remarkably well-preserved, making this a truly extraordinary find.
The fossil reveals R. robustus gripping the lower jaw of Psittacosaurus with its left forepaw while its left hind paw clings to the dinosaur’s hind limb. The mammal’s teeth are embedded in the prey’s ribs. Dr. Mallon and his colleagues determined that the mammal was an aggressor rather than a scavenger based on several factors. The absence of bite marks on the skeletons, typically indicative of scavenging, and the intertwined positions of the two animals strongly suggest that this was an act of predation frozen in time.
While the outcome of the encounter remains unknown, Dr. Mallon suggests that it was possible for the mammal to emerge victorious. He draws parallels with the present-day natural world, where smaller carnivores successfully attack much larger animals. Instances such as weasels taking down hares several times their body weight or wolverines hunting caribou or even moose exemplify this phenomenon.
Ultimately, both the mammal and dinosaur met their demise during this ancient battle. The circumstances of their deaths suggest that they were suddenly buried together by a mudslide triggered by a volcanic eruption.
This extraordinary fossil provides a unique window into a long-gone world, challenging our understanding of the dynamics between early mammals and dinosaurs while showcasing a dramatic and enthralling moment frozen in time.
