(CNN) – Billions of Tyrannosaurus rex, also known as T. rex, roamed North America during its fascinating reign as large predators, according to a team of researchers who have set themselves the difficult task of making calculations.
Paleontologists at the University of California, Berkeley, set out to determine the number of T. rex that lived during the Cretaceous, about 65 to 98 million years ago. And they knew it wasn’t going to be an easy task.
Fossil evidence
Fossils have long been used to deepen what we know about extinct creatures, such as dinosaurs. But experts say it can be a challenge to use these remnants to calculate population density and abundance.
“There is no information to make a calculation,” said Charles Marshall, director of the Museum of Paleontology at the University of California. Marshall was part of the investigation team. «If you find an Easter egg in your garden, how can you calculate how many Easter eggs there were? It just can’t be done. The information is needed from elsewhere. For example, the density of Easter eggs, where they can be found and how many years have been laid Easter eggs in gardens.
Previously, researchers have tried to estimate things such as the possible size of the range of tyrannosaurs. Also your basic energy needs. So this is a nice extension of the previous work. And it includes a lot of up-to-date information about the tyrannosaurus, “said Nizar Ibrahim, a paleontologist at the University of Portsmouth (UK) and a National Geographic explorer who was not involved in the research.
“We just have to keep in mind that all these interesting studies come with a certain uncertainty. There are many things we still don’t know about dinosaurs, including a Hollywood star like T. rex, “Ibrahim added in an email.
North America had 20,000 T. rex at one time
By studying fossil records, density data, and climate data, the team at the University of California, Berkeley estimated that there were probably about 20,000 adult T. rex, living throughout North America and existed at one time. dat. This was explained by researchers in a study published in the journal Science, means that about 2.5 billion predators have lived and died in the approximately 2.5 million years that dinosaurs lived.
For the first time, the team also calculated the longevity of the dinosaur. Using the scientific literature and expert opinion, they estimated that the probable age of sexual maturity of a T. rex was 15.5 years and that its lifespan could be up to 20 years. The average body mass of an adult dinosaur was about 5,200 kilograms, and the increase in sexual maturity could lead to 7,000 kilograms.
From these calculations, the team concluded that each generation of T. rex lasted about 19 years and that there was one dinosaur for every 100 square kilometers.
The study can help to understand the change of a species
The researchers also determined that with a population of 20,000 dinosaurs and about 127,000 generations of species, there would be a total of 2.5 billion dinosaurs.
The researchers’ methods “seem very informative, while also showing the current limits of what can be done with what we know now,” said Jason C. Poole, head of fossil training at the Bighorn Basin Paleontological Institute and artist. which was not part of the study.
“I’m sure it will open the door to further address the issues of population density and what this means over time,” Poole added in an email. “So this could really help us understand things like changing a species over time in relation to the evolution and change of ecosystems,” he added.
The study estimates that the population density of the species was 3,800 carnivorous dinosaurs in an area the size of California, but only two in an area the size of Washington.
T. rex fossils are unusual
On the other hand, the results also allowed the report’s authors to determine that only fossil remains of T. rex are preserved in a proportion of 1 in 80 million.
“The big impact of this study may be that it shows how rare fossils are. In the sense that they represent only a small part of the individual organisms that existed, not to mention the depth of time, as in what happens in a few thousand to a million years, “said Poole.
“In a way, it was a paleontological exercise in how much we can know and how we can know it,” said Marshall, co-author of the study and professor of integrative biology and Earth and planetary sciences at UC Berkeley. in a statement.
“It’s amazing how much we really know about these dinosaurs and, from there, how much we can calculate. Our knowledge of T. rex has expanded greatly in recent decades due to more fossils, more ways to analyze them, and better ways to integrate information about the many known fossils, ”he said.
Beyond T. rex
Ibrahim also highlighted other possibilities derived from this study.
“There are many things we don’t know about the physiology, behavior and ecology of tyrannosaurus feeding, but this study offers an interesting approach to estimating the abundance and conservation rate of dinosaurs,” he said.
“I would like to see it applied to other known dinosaurs from abundant fossils. Looking at a wider range of dinosaurs – predators and prey – could allow us to better compare the animal communities of the dinosaur era with the modern ones. ‘
“But we are only looking at the surface, and even with this interesting study, there is still a long way to go until we can confidently apply such approaches more widely to the study of dinosaurs,” he added.
CNN’s Kristen Rogers contributed to this report.