Every dinosaur-movie lover knows the Tyrannosaurus rex (T. rex) as massive predators that chase around all its prey alone as if it was a one-T. rex show back in its history. But was it really rare?
A recent study by a research team at the University of California, Berkeley estimated the number of T. rex that must have lived through 127,000 generations at 2.5 billion.
Through analyzing detailed anatomy and rigorous statistics such as its geographical size, body mass, growth pattern, life expectancy, duration of one generation, the team concluded that around 20,000 adult T. rex likely existed together once during the Cretaceous era.
Each generation of these 40-foot-long, 14,000-pound dinosaurs is guesstimated to have lasted about 19 years and would've used up a total of 900,000 sq. miles of North American continent, given that each needed about 40 square miles of land.
"With these numbers, we can start to estimate how many short-lived, geographically specialized species we might be missing in the fossil record. This may be a way of beginning to quantify what we don't know," said study lead author Charles Marshall, director of the University of California Museum of Paleontology, in a statement.
Marshall and his student team calculated how much energy the T. rex needed to keep their generation going on and found that the T. rex reached sexual maturity somewhere around 14 to 17 years old and lived at most 28 years. The duration of a single generation and the total time that T. rex existed before extinction 66 million years ago, study says.
"A very large killer with very large teeth would not have come to anyone's mind if we had no fossil record, so it's not just more than wonderful and beyond imagination, but it's real. Like Godzilla, but it's real. I think we feel small, and certainly, T. Rex makes us feel young and weak," remarked Marshall.
The study was published in the Science journal, last month.