Rewriting History: T. Rex‘s Transcontinental Journey

For decades, the Tyrannosaurus Rex, or T. Rex, has reigned supreme in our imaginations as the quintessential North American predator. towering at nearly 4 meters tall at the hips and stretching over 12 meters in length, this apex predator dominated the Late Cretaceous period, roughly 67 to 66 million years ago. Fossil discoveries across Montana and South Dakota have cemented its place in the American landscape. but what if the T. Rex wasn’t a native after all?

Unearthing the Truth: New Evidence Points East

Challenging conventional wisdom, a groundbreaking study published in Royal Society Open Science on May 7, 2025, proposes a compelling new narrative: the T. Rex’s ancestors migrated from Asia. This research suggests that the iconic dinosaur crossed a now-submerged land bridge connecting Asia and North America, eventually evolving into the formidable predator we know today.

Our model shows that the ‘grandfather’ T. Rex is most likely to come from Asia. He crossed the Bering Strait which was then the land between Siberia and Alaska.
Cassius Morrison, university College London

This theory isn’t entirely new. Some paleontologists have long suspected an Asian connection, but this latest research provides the most robust evidence yet.

Deciphering the Past: Methodology and findings

The research team meticulously analyzed the geographic location and age of various Tyrannosaurus species discoveries. By constructing evolutionary trees and considering ancient climate conditions, they pieced together a compelling migration timeline. Their analysis indicates that the ancestors of T. Rex likely journeyed from Asia to North America approximately 72 million years ago, during the Campanian-Maastrichtian transition.

While the T. Rex ultimately flourished in North America, the study highlights the crucial role of Asia in its evolutionary history. This aligns with previous anatomical comparisons, suggesting closer similarities between T. Rex and Asian dinosaurs like Tarbosaurus than with its North American relatives, such as Daspletosaurus.

This is in line with the previous findings that T. Rex is closer to anatomy with Asian dinosaurs such as tarbosaurus than American relatives such as Dasphletosaurus.
Cassius Morrison, University College London

paleontologist Steve Brusatte from the University of Edinburgh, in a 2016 study, lauded the new findings, stating that T. rex, while undeniably an American dinosaur, was, in fact, an immigrant from Asia.

Climate’s Crucial Role: Shaping a Giant

Beyond its origins, the study delves into the factors that allowed T. Rex and related species, like Megaraptor, to attain such immense sizes. One key element was climate change. Around 92 million years ago, the Earth experienced the Cretaceous Thermal Maximum (CTM), a period of intense global warming driven by volcanic and tectonic activity. Sea surface temperatures soared to a staggering 35°C.

Following this peak, temperatures and greenhouse gas levels plummeted. This climatic shift lead to the extinction of many large dinosaurs, opening up ecological niches for tyrannosaurids and megaraptors. These adaptable creatures seized the possibility,evolving into the giants that roamed the Earth.

The Bigger Picture: Climate, Evolution, and the King of Dinosaurs

This research underscores the profound impact of climate change on the evolution of life. The T. Rex’s rise to dominance was not solely a matter of genetics or chance; it was intricately linked to environmental shifts. Cooler climates,in particular,appear to have fostered the growth and growth of these colossal predators.

The study serves as a powerful reminder that evolution is a dynamic process shaped by external factors, with climate playing a pivotal role.As scientists continue to explore the fossil record, we can expect further revelations about the complex interplay between life and the environment.

The Next Chapter: Unearthing Asian Ancestors

The quest to understand the T. Rex’s origins is far from over. Scientists are now eagerly awaiting the discovery of ancestral T.Rex fossils in Asia. Such findings would provide further validation of the migration theory and shed even more light on the evolutionary journey of this iconic dinosaur. The story of the T. Rex is a testament to the power of scientific inquiry and the ever-evolving nature of our understanding of the past.