Scientists Have Reevaluated the Total Number of Tyrannosaurus Rexes That Ever Existed on Earth.
A new study reveals that approximately 1.7 billion T. rex individuals existed throughout our planet’s history.
About 1.7 billion T. rex once existed on our Earth.
In April 2021, a study published in the journal Science estimated that up to 2.5 billion T. rex individuals lived between 68 and 65.5 million years ago on Earth. However, according to the new research published in the journal Palaeontology, the actual number may be closer to 1.7 billion.
The study’s author, Eva Griebeler, an evolutionary ecologist at Johannes Gutenberg University in Mainz, Germany, stated that the new model took into account information about T. rex that the original study’s authors overlooked. This led to a decreased estimated population of the dinosaurs.
Charles Marshall, a paleontologist at the University of California, Berkeley, and the lead author of the 2021 study, noted that this new result is more comprehensive.
In the initial study, Marshall’s team created a complex model that considered several different variables, including average body mass, population density, approximate geographic range, age of maturity, number of eggs laid, average lifespan, survival rate, and generation time.
This allowed them to estimate how many T. rex could survive together. The model revealed that each generation of T. rex could consist of about 20,000 individuals. Additionally, there were about 125,000 generations over the 2.5 million years they existed, resulting in a total of 2.5 billion T. rex.
However, researcher Griebeler disagreed with some of the data used in this model. She believes that Marshall’s team overestimated the survival rate and egg-laying capability of T. rex, as well as the number of generations that existed during this time. These factors skewed the results.
Griebeler’s research shows that these values appear to be more in line with those of modern birds and reptiles. When these values were incorporated into an updated model, it revealed that there were 19,000 individuals in each T. rex generation. Meanwhile, there were only about 90,000 generations, meaning the maximum number of T. rex that could have existed is 1.7 billion.
Regardless of the exact figure, both studies raise an intriguing question: Where are all the T. rex bones? If Griebeler’s predictions are accurate, it suggests that we have only found fossils of 0.0000002% of these giant dinosaurs. According to both researchers Griebeler and Marshall, this is an important question that warrants further investigation.
