2.5 Billion T. Rex Inhabited the Planet, Researchers Say (axios.com) 46
For the first time, scientists have estimated how many Tyrannosaurus rex, the so-called king of dinosaurs, once roamed the Earth. From a report: The number is staggering: 2.5 billion Tyrannosaurus rex lived and died during the roughly 2.4 million years the species survived on the planet, according to a new study set to be published in the journal Science on Friday. The study may help contextualize the fossil record and the rarity of finding certain fossilized prehistoric organisms, according to lead researcher Charles Marshall, director of the University of California Museum of Paleontology. "I mean, to me, it's just amazing we could have come up with a number," Marshall told Axios. "Some people have asked me, 'How does your number compare to other numbers of the total that have ever lived?' The answer is it doesn't because there weren't any."
Not surprising, Get It On, Bang a Gong (Score:2)
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It is more interesting to know... (Score:5, Funny)
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I have never laughed so loudly
thank you for recalling it and sharing.
And 100 million vegansauruses (Score:4, Funny)
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Go ahead, break my balls for the shitty comma.
This is WHY I've been lobbying for a "-1 misplaced, comma" mod option but until they add it I can't help.
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-- I ignore anonymous replies to my comments and postings.
No you didn't ;)
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Way to go with that comma - you made your fourth-grade teacher cry.
Does anyone believe this number? (Score:1)
Does anyone believe this number? I'm sure they have an explanation, but it will be mostly bullshit.
Re:Does anyone believe this number? (Score:5, Interesting)
After thinking about it, the number seems ballpark reasonable. It's probably not less than 2.5 billion or greater than 250 billion, so I'm willing to accept it as a decent estimate. Perhaps additional future discovers will help us fine-tune it, but unless there's some truly extraordinary evidence to completely upset our present understanding, I really don't see it moving more than an order of magnitude in either direction.
Re:Does anyone believe this number? (Score:5, Insightful)
Having read nothing other than the summary...
I highly recommend reading TFA. It's not very long and answers most of the questions in this discussion.
Seems reasonable [Re:Does anyone believe...] (Score:3)
Having read nothing other than the summary, I'm assuming it's a total over a time period.
Yes, I'd assume.
Tyrannosaurus Rex was Cretaceous, a period which lasted nearly 80 million years. Not sure that Rex were around for all of that, but figure maybe a quarter of that with T. Rex roaming the planet. 2.5 billion divided by 20 million, times an estimated lifepan of 25 years, comes to about 3,000 on the planet at any given time.
The dead outnumber the living [Re:Seems reasonable (Score:3)
Heard somewhere and I think the math works out.. There are more humans alive today than have ever died.
That would be fascinating... but not true, I'm afraid.
The dead outnumber the living by about 15:1.
https://www.livescience.com/18... [livescience.com]
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I do know that t-rex bones are huge, so I am guessing that they had a better chance of becoming a fossil. I don't know how that would play into the equation.
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Well, given that the math was done to try to figure out why the fossils are so rare, it seems a fair question.
I'm not sure that the size of the creature matters very much in the context of fosilisation though. As I understand it, fossils are only found if the body was somehow well preserved, which means it must be free of bacteria and insects, in most cases. This nearly only happens if the animal dies a sudden death, like from an erupting volcano, falling into a swamp or tar pit, avalanche, limestone/mudsli
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And this is why I love Slashdot. Solid conjecture, with an explanation. makes for good learning and good research of idea's
Title is misleading (Score:5, Informative)
If you read the article, the actual estimate is only 20,000 individual T-rex alive at any given time. They then multiply by the amount of time T-rex was on the planet (much longer than humans), to get the total number that ever lived (a fairly useless, but impressive sounding number).
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Not useless at all. It provides the basis for estimating the chance of fossil preservation.
Re:Title is misleading (Score:5, Interesting)
Perhaps I missed something, but isn't part of the input of how many T-Rexes were alive based on the fossil record?
Estimating the fossil record based on the fossil record is begging the question...
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1000 per year (Score:5, Informative)
So 25 billion over 2.4 million years is saying there were only a thousand born each year (to within a rounding error). A quick search shows that they think they had a lifespan of 30 years, so the population of T. Rex was on average, 30,000 individuals. That sounds reasonable.
I expect the reality is far more were hatched each year, but they had high child mortality. But I haven't looked at the study or any data outside of my imagination to assert that.
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about 20,000 T. rex were alive at any given time that the species lived on the planet.
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Which is around the same number of polar bears currently alive (20,000 - 25,000).
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So 25 billion over 2.4 million years is saying there were only a thousand born each year (to within a rounding error). A quick search shows that they think they had a lifespan of 30 years, so the population of T. Rex was on average, 30,000 individuals. That sounds reasonable.
I expect the reality is far more were hatched each year, but they had high child mortality. But I haven't looked at the study or any data outside of my imagination to assert that.
Yeah, summary and linked article don't mention it explicitly, but the study is talking about adult T. Rex.
- The relationship, used in population ecology, generally states that species with larger body sizes tend to have lower population densities.
- The researchers then computed the average body mass of a T. rex, settling on a mean of 5,200 kilograms (roughly 11,460 pounds).
- Using the body mass, the team calculated that the species had a population density of around one individual per 40 square miles.
Anothe
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I expect the reality is far more were hatched each year, but they had high child mortality.
I'd bet that the hatchling T. Rexes were really cute and playful. It would have been really tempting to take one in as a pet.
Of course, things would soon get out of hand, and the increasingly vicious adolescents would be have to be let loose in the woods outside of town, with predictable results.
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humans alive today larger than number dead? (Score:1)
Much better article (Score:5, Informative)
Here is a much better science article at SciNews [sci-news.com]:
"... at any one time was about 20,000 individuals ...", and "... the species persisted for 127,000 generations ...". Also, each generation lasted about 19 years.
Now picture them all in a Conga line... (Score:2)
Shocking small number! (Score:3)
Not impressed (Score:2)
The ugliest and worst predator on the planet ever, humans, are far more abundant.
Careful (Score:2)
What this really shows is the vanishingly small chance that a creature will be fossilized - around 1 in a BILLION.
There are only about 30 trex fossils extant today.
Think about that ratio. That means if we all died now and an alien race examined earth they would find only about 112 human fossils - mostly from 1100AD and earlier.
Think how 'scientific' most projections would be considered, based on sample sizes that small?
Paleontologists need to be careful they don't show their cards here too clearly or they'