From these estimates, they also calculated that each generation lasted about 19 years, and that the average population density was about one dinosaur for every 100 square kilometers.

Then, estimating that the total geographic range of T. rex was about 2.3 million square kilometers, and that the species survived for roughly 2 1/2 million years, they calculated a standing population size of 20,000. Over a total of about 127,000 generations that the species lived, that translates to about 2.5 billion individuals overall.

根据这些估计，他们还计算出每一代持续约 19 年，平均种群密度约为每 100 平方公里一只恐龙。

然后，估计霸王龙的总地理范围约为 230 万平方公里，并且该物种存活了大约 250 万年，他们计算出常备种群规模为 20,000。该物种总共生活了大约 127,000 代，这意味着总共有大约 25 亿个体。

https://scitechdaily.com/paleontologists-stunning-conclusion-2-5-billion-t-rexes-roamed-north-america-over-the-cretaceous-period/#:~:text=Rexes%20Roamed%20North%20America%20Over%20the%20Cretaceous%20Period,-TOPICS%3ADinosaursEvolution&text=Analysis%20of%20what's%20known%20about,were%202.5%20billion%20over%20time.

https://twitter.com/zhu0588/status/1539007625425129472