2.5 billion T. Rexes have traveled the Earth, but not all at once: Study

A Tyrannosaurus rex looks scary enough. Imagine 2.5 billion. This is how many of the fierce dinosaur kings traveled the Earth over a couple of million years, according to a new study.

Using calculations based on the body size, sexual maturity, and energy needs of the creatures, a team at the University of California, Berkeley, discovered how many T. rex lived for 127,000 generations, according to a study in the journal Science on Thursday. . It is a unique number, but only an estimate with a margin of error the size of a T. rex.

“That’s a lot of jaws,” said the study’s lead author, Charles Marshall, director of the University of California’s Museum of Paleontology. “It simply came to our notice then. It’s a lot of claws. “

The species roamed North America for approximately 1.2 million to 3.6 million years, meaning the population density of T. rex was small at any time. There would be about two in one place the size of Washington, DC, or 3,800 in California, according to the study.

“Probably, like a lot of people, I literally took a double take to make sure my eyes hadn’t been fooled when I first read that they had lived 2.5 billion T. rexes,” said the paleobiologist at Macalester College. , Kristi Curry Rogers, who was not part of the study.

Marshall said the estimate helps scientists calculate the rate of preservation of T. rex fossils and underscores how lucky the world is to know them. About 100 fossils of T. rex have been found, 32 of them with enough material to be believed to be adults. If there were 2.5 million T. rex instead of 2.5 billion, we probably would never have known they existed, he said.

Marshall’s team calculated the population using a general biology rule that says the larger the animal, the less dense its population will be. They then added estimates of how much energy the T. rex carnivore needed to stay alive, between a Komodo dragon and a lion. The more energy is needed, the less dense the population. They also noted that T. rex reached sexual maturity between the ages of 14 and 17 and lived to a maximum of 28 years.

Given the uncertainties about the length of generation of the creatures, their scope and the time they walked, the Berkeley team said the total population could reach up to 140 million or up to 42 billion, with 2.4 billion as an average value.

The science about the largest carnivores living on earth is ever important, “but the truth, as I see it, is that these kinds of things are a lot of fun,” said Purdue University geology professor , James Farlow.