Before the dinosaurs, Earth was a warmer world of supercontinents

Space · Published 26 October 2026 Swipe more like this →

In short: Long before the era of Tyrannosaurus rex, our planet underwent radical transformations. From the mysterious origins of life nearly 4 billion years ago to the assembly of massive landmasses, the Earth's history is a story of shifting continents, fluctuating seas, and a climate far warmer than our own.

The history of life on Earth remains one of science's greatest mysteries, specifically how life first emerged from non-living matter. However, current scientific estimates suggest that life first appeared on our planet approximately 3.8 billion years ago. This ancient beginning set the stage for a long geological journey that eventually led to the Mesozoic Era. The image of Diplocaulus serves as a visual marker for this deep history. This timeline precedes the famous age of the dinosaurs.

By the time the Cretaceous Period began 145 million years ago, the Earth's geography was dominated by the supercontinent Pangea. Formed roughly 335 million years ago, Pangea began to break apart by the end of the Jurassic Period. This fragmentation continued throughout the Cretaceous, eventually moving the continents into positions very similar to where they sit today. During this time, the planet was significantly warmer than the present day, with little to no ice at either the North or South Poles. The Cretaceous Period represents the final chapter of the Mesozoic Era. It followed the Jurassic Period and preceded the Paleogene.

The Cretaceous was also defined by high sea levels, which at times were 170 metres higher than today's levels. These waters created shallow seas that divided landmasses, such as the Western Interior Seaway. This massive body of water was over 3,000 kilometres long and reached depths of 760 metres. In these environments, creatures like the mosasaur Platycarpus thrived, hunting fish and ammonites while temperate rainforests grew in the ice-free polar regions. Between 100.5 million and 66 million years prior to now, the Late Cretaceous Epoch occurred. During this time, the Western Interior Seaway split North America into two distinct landmasses.

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