Scientists estimate that about 20,000 adult tyrannosaurs walked across North America during the Cretaceous period.
Until now, no one has succeeded in calculating the number of long-extinct animals.
The authors of the work stated that the uncertainty in the calculations is great: as a result, it turned out that 20 thousand individuals walked across North America in the Cretaceous period.
However, with 95% probability, we can only say that the real number of tyrannosaurs was from 1,300 to 328 thousand. Thus, the total number of individuals in North America could be from 140 million to 42 billion.
To make these calculations, the researchers used computer simulations based on data published by John Damut of the University of California, Santa Barbara. In them, the author connects the body mass of any living being with the population density. This was called Damut’s law.
The authors further calculated that the probable age of sexual maturity of a Tyrannosaurus rex is 15.5 years; its maximum life span is approximately 20 years; the average body weight for an adult is about 5 200 kg. The authors also used data on how quickly the tyrannosaurus grew during its life.
Based on these estimates, the researchers calculated that each generation of tyrannosaurs lived for about 19 years, and the average population density of North America was about one dinosaur for every 100 square kilometers. km. The total geographic range of Tyrannosaurus rex is about 2.3 million square meters. km, where they lived for about 2.5 million years. Further, the authors calculated the constant population size – 20 thousand. In total, this species lived about 127 thousand generations, which in total is about 2.5 billion individuals.