T. Rex Grew Slower Than We Thought!

The fearsome Tyrannosaurus rex, a contender for Earth's most massive land predator, may have achieved its formidable size at a more gradual pace than scientists once thought. New analysis of the microstructure in fossilized leg bones from 17 specimens suggests that T. rex took around 40 years to reach its full weight of approximately 8 tons. This timeframe is about 15 years longer than prior estimations, revealing a slower growth trajectory.

Researchers identified novel growth marks within the bones, visible only under polarized light, which indicate a more extended period at juvenile and subadult stages. This flexible growth pattern, with varying annual rings reflecting resource availability, allowed T. rex to survive harsh periods and outcompete other carnivores. The study, involving more specimens and a new statistical approach, also revises the estimated lifespan of T. rex to between 45 and 50 years, extending beyond the previously accepted 30 years.

Tyrannosaurus rex roamed western North America during the late Cretaceous Period, millions of years before the asteroid impact that ended the age of dinosaurs 66 million years ago. This giant predator, known for its immense size, powerful bite, and massive head, hunted large herbivorous dinosaurs. The extended growth period likely offered evolutionary advantages, allowing younger T. rex individuals different feeding strategies compared to their larger, older counterparts, potentially utilizing scavenging or focusing on live prey.