How Many Tyrannosaurus Rexes Ever Lived on Earth? Here’s a New Clue

That contains the metabolism. Dinosaurs are now not regarded as coldblooded like modern-day lizards, however they have been most likely not as warm-blooded as mammals. So Dr. Marshall’s workforce assumed a physiology in between that of meat-eating mammals and Komodo dragons. They additionally needed to account for some uncertainty about the place the dinosaurs lived in North America. Paleontologists don’t know whether or not the vary of T. rex was restricted to the place fossils have been discovered within the western United States and Canada, or if it stretched to different locations with related climates again then, from Alaska to the East Coast.

Because a lot is unknown about dinosaurs, the scientists weren’t trying to provide you with a single definitive reply, however to offer limits on what they thought a believable quantity might need been. “For most of the paleontological data, I don’t know how to guess a number,” Dr. Marshall stated. “But I can tell you what a good minimum is, and what a good maximum is.”

The calculations yielded a probably standing inhabitants of 20,000 Tyrannosaurus rex adults. That would point out a sparse distribution equal to 2 adults in an space the scale of Washington, D.C.

But the uncertainty round that estimate was very broad. The identical pc simulations indicated, with 97.5 p.c likelihood, that there have been at the very least 1,300 adults however no more than 328,000.

If the 20,000 quantity is appropriate, over the two.four million years that T. rex walked the Earth, there would have been a whole of some 2.5 billion adults that ever lived.

But even Dr. Marshall thinks the 20,000 quantity is probably going low. “It just seems inconceivable you can last a couple of million years with those few individuals,” he stated. “You just need some horrible plague or something and you’re gone.”

He stated he thought the inhabitants might have been tens of 1000’s or perhaps 100,000 or 200,000. A big a part of the uncertainty is that Damuth’s regulation shouldn’t be absolute. Jaguars and noticed hyenas are each meat-eating mammals of comparable measurement, however the inhabitants density of hyenas is a few 50 occasions increased.

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