Footprints Reveal that Big Theropod Dinosaurs Lived Near the Antarctic Circle

Recent discoveries indicate large theropod dinosaurs inhabited Australia’s south coast, reports IFLscience. This region once connected to Antarctica housed these giants when it faced extended winter darkness.

The Wonthaggi Formation, located southeast of Melbourne, contains fossils dating back 120 to 128 million years. It has revealed various small herbivorous dinosaurs and ancestral mammals, offering insight into the life that existed after significant events, such as the asteroid impact. Moreover, it showcases the southernmost evidence of Cretaceous birds.

Australia’s position further south during that era created a unique ecological environment. Despite facing long winter nights, the region remained warmer due to elevated global temperatures and the equatorial warm waters. Accessibility to fossils locked in glaciers is challenging, making the Wonthaggi Formation a vital source for understanding this distinctive ecosystem.

Theropod Footprint Discovery

Although theropod bones exist in the area, they are not as numerous compared to the herbivorous ornithopods that likely represented their main prey. Interestingly, 18 theropod footprints have been identified, overshadowing just four ornithopod prints and two unidentified tracks. Among these footprints, 15 belong to large theropods, indicating significant carnivorous activity.

Professor Anthony Martin from Emory University stated, "These numerous tracks are the best evidence yet that these polar environments supported large carnivores." He suggests these theropods likely preyed on smaller dinosaurs, fish, and turtles.

The largest identified track measures 47 centimeters (18.5 inches) long. It stands as the biggest theropod footprint from that era found in southern Australia. Martin deduces its hip height reached around six feet, comparable to the height of a tall human.

Survival in Polar Conditions

The ability of dinosaurs to survive polar winters continues to intrigue palaeontologists. Since the 1970s, when Dr. Thomas Rich and Professor Pat Vickers-Rich initially revealed their presence, questions have arisen about their survival strategies. Did these dinosaurs migrate, hibernate, or adapt to limited food resources?

While the footprints cannot directly answer this question, they illustrate that at times, ample medium-sized prey allowed large theropods to thrive in the region. Contrarily, the limited presence of large herbivores and smaller carnivores raises additional questions.

Martin noted, "Our find of many theropod tracks confirms that various dinosaurs lived and walked where their bones were found." This discovery highlights that dinosaur tracks were more common than previously recognized.

The persistence of co-author Melissa Lowery from Monash University revealed significant discoveries during the pandemic. Convenience allowed her to conduct prospecting during Victoria's extended lockdowns, leading to identifying many more dinosaur tracks.

Preserving the Footprints

Most tracks lie within tidal zones, submerged twice daily, complicating discovery efforts. The tracks were located in muddy conditions that likely arose during the landscape's early summer thaw. Yet, researchers still remain uncertain about whether dinosaurs lived there during the winter. "It would have been frozen over, and dinosaurs walking on ice don’t leave tracks," Martin noted. Despite these uncertainties, the presence of juvenile footprints suggests potential nesting activity within the area.

Earlier, SSP reported that digging holes at the beach can be dangerous.