How many were there?

Scientists have listed the total number of tyrannosaurs that have ever lived on Earth. As a result, they got 1.7 billion tricks.

A study published in the journal Science in April 2021 estimates that there were as many as 2.5 billion T. rex individuals roaming the planet between 68 and 65.5 million years ago. But a new study, published April 18 this year in the journal Paleontology, casts doubt on that figure, suggesting the true figure is probably closer to 1.7 billion.

Study author Eva Griebeler, of the Johann Gutenberg University of Mainz in Germany, said her new model takes into account information about T. rex that the 2021 authors had overlooked.

In the original study, the team created a complex model that took into account a number of different variables:

• Average body weight.
• Population density.
• Approximate geographic area.
• Puberty age.
• Number of eggs laid.
• Average life expectancy.
• survival rate.
• time of generations.

All these indicators made it possible to estimate how many T. rex could survive side by side. The model showed that each generation of T. rex probably consisted of about 20,000 individuals, with about 125,000 generations in its 2.5 million years of existence. That’s a total of 2.5 billion T. rex.

What was not taken into account

However, the Griebeler disagreed with some of the data included in this model. He believes the authors skewed the results by exaggerating the survival rates and egg-laying abilities of tyrannosaurs and the number of generations that existed at that time.

Griebes’ study, published shortly after the original, suggested that these values ​​were probably more similar to those seen in modern birds and reptiles. Considering these values ​​in the updated model, Each generation of T. rex had 19,000 individuals, with a total of about 90,000 generations, so the maximum number of T. rex that could exist was 1.7 billion individuals.

Whatever the exact number, both studies raise an interesting question – where are all the T. rex bones? If the Griebes’ predictions are correct, that means we only found the remains of 0.0000002% of these giant dinosaurs. This is an important question that requires further research.