2.5 Billion Tyrannosaurus rexes

[suspsy]

https://science.sciencemag.org/content/372/6539/284.full?fbclid=IwAR03Abrv3UCPESoZu8_ImgLMRDOzeTnY_4vtkpkq5Kta5QXa2eAM9nmS92U

Yes, according to this paper, the total number of Tyrannosaurus rexes to have existed was 2,500,000,000. However, there would have been only around 20,000 alive at the same time.

It makes you wonder how many more specimens will be uncovered in our lifetimes. Perhaps even one or a few bigger than Scotty.

https://phys.org/news/2021-04-rexes-billions.html?fbclid=IwAR2iQsoNWrXRnXf-a6SLqCOkg46rsXmJE3OzLBCqzxGZWpfWBaWHBnLQNEo

[Carnoking]

2.5 billion existed and I never even got to see one. 

[MLMjp]

That's what hell looks like for some people here on the forum

[Carnoking]

I can now justify owning 2.5 billion t rex models. One for each.

[postsaurischian]

   Pure speculation.

[andrewsaurus rex]

that works out to about 1250 new T rexes per year being born and surviving to adulthood.  That's with T rex being around about 2 million years.  That seems very conservative to me, considering T rex was all over Laramidia.   

Edit: if we assume there were only 20,000 around at any one time, that would imply that T Rex only had a lifespan of about 16 years, which is much lower than what I've been led to believe.

[Crackington]

Thinking from another perspective, this shows the astronomical odds on an individual being fossilised. Over 2 billion rexes but only 100 fossils found.

Also, we must be getting pretty close to 2 billion brands making Rexes by now too 😉

[andrewsaurus rex]

ha...eventually there will be more rex models made than there were actual rexes.

ok, so I just looked up the lifespan of T rex and it's quoted as 30 years.  Don't know how accurate that is but seems a reasonable number.

I haven't read the article because it is loading funny and I can't get it to scroll, so i'll work with the numbers quoted in this thread.  1250 Rexes born per year, 20,000 around at any one time.  I was assuming in my first post that they were all adults but clearly not. 

So when does a Rex become and adult?  Age 20?  Nice round number.  So all the Rexes under 20 we will call juveniles of various ages.  Just by straight division that would give 645 of each age from newborn (age 0) to age 30.  But there has to be about 1250 being born each year.  Adult mortality would be say 1/9 that of juvenile mortality (the mortality rate would decrease as the animal aged, I assume).  So that would mean of 20,000 Rexes there would be roughly 1615 adult T rexes (between age 20 and 30) at any one time.

Edit:  If I knew the size of Laramidia i could work out the average size of an adult T rex's 'territory'.....assuming individuals had their own territory.   If nothing else i could determine the density of the T rex population.   Anyone know an estimated square mileage for Laramidia?

Edit again:  i looked up the area of North America and assumed Laramidia was about 1/4 the size of it.  So that gives the size of the territory for each adult Rex as 1476 square miles.  About 30 miles by 50 miles.  That does not seem unreasonable to me, keeping in mind there would also be about 11 juvenile T rexes between the ages of newborn and 19 in that same territory..