Study Reveals T. rex Ancestors Migrated from Asia to North America via Land Bridge 70 Million Years Ago

A recent study sheds light on the origins of Tyrannosaurus rex, suggesting its ancestors crossed a land bridge from Asia into North America about 70 million years ago. This finding adds a new layer to the ongoing debate among paleontologists about the king of the dinosaurs.

Led by Cassius Morrison from University College London, the research used mathematical models to analyze fossil records and the family tree of T. rex. These models indicate that T. rex’s ancestors, known as tyrannosaurids, arrived via the Bering Strait, now located between Siberia and Alaska.

Interestingly, these early tyrannosaurids were likely fewer in number compared to the herbivorous dinosaurs they hunted. Morrison compares this to today’s apex predators, like lions. “Being fewer means fewer are preserved in the fossil record,” he explained.

To tackle gaps in this record, Morrison’s team incorporated climate and environmental data into their models. He emphasized that new findings could still emerge, as there might be undiscovered T. rex ancestor fossils in Asia.

The study also revealed that during periods of declining global temperatures, tyrannosaurids grew rapidly in size. This growth coincided with the extinction of another group of large meat-eating dinosaurs, opening up space in the food chain.

By the time dinosaurs went extinct, T. rex could have weighed up to 9 metric tons—similar to a large African elephant. This massive size likely emerged due to both dwindling competition and a changing climate.

Charlie Scherer, a co-author of the study, noted this research illuminates how these gigantic dinosaurs appeared in North and South America and why they grew so large in the Cretaceous period. “The extinction of carcharodontosaurids likely allowed tyrannosaurs to expand,” he said.

Steve Brusatte, a paleontologist at the University of Edinburgh, commented on the study’s robust analysis. He highlighted the relationship between climate and dinosaur size. “Even the largest dinosaurs were affected by the weather. Cooler climates helped them grow,” he stated.

This research expands our understanding of how climate change impacted dinosaur evolution. It’s fascinating to see how historical events shape life on Earth, just as they do today.

The study was published in the Royal Society Open Science. You can explore more about dinosaur evolution and climate’s influence on species in this insightful piece.

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