2.5 billion T. rex roamed Earth, but not all at once

[Eldorado]

One Tyrannosaurus rex seems scary enough. Now picture 2.5 billion of them.

That’s how many of the fierce dinosaur king probably roamed Earth over the course of a couple million years, a new study finds.

Using calculations based on body size, sexual maturity and the creatures' energy needs, a team at the University of California, Berkeley figured out just how many T.Rex lived over 127,000 generations, according to a study in Thursday’s journal Science.

It’s a first-of-its-kind number, but just an estimate with a margin of error that is the size of a T. rex.

AP news report

Absolute abundance and preservation rate of Tyrannosaurus rex

Science Mag