New Analysis Shows Dinosaurs Not As Heavy As Previously Believed.

Cognitive Dissident writes "Discovery.com has an article on a new study using computer modeling to estimate the actual amount of flesh needed to cover the skeletons of dinosaurs. Based on a comparison with modern animals, it indicates that these animals could have weighed dramatically less than has been previously estimated. 'A huge Brachiosaur, once thought to weigh 176,370 pounds, is now believed to have weighed 50,706 pounds.' That's only about two-and-a-half times the weight of a modern African elephant. If other evidence can be reconciled with this, many estimates of the ecosystems dinosaurs lived in will also have to be revised."

Comments

Dino Booty

[pd0x]

Dinosaurs. Not heavy, just big boned.

What about footprints?

[fotoguzzi]

Is enough known about footprint formation to estimate the mass of the creature that made them?

[Sorry if this is a repeat. I do not see my first attempt.]

Re:What about footprints?

[wvmarle]

I doubt a footprint can give any useful measure of the weight of the animal that made it.

Too many variables. Walking speed and method will influence it, as it affects the impact between foot and soil and the time the foot is pushing down on the soil. Exact original soil content (water content and particle size). How deep the soft layer of soil really was.

Elephant metric system

[Anonymous Coward]

pounds? for a minute there I thought we were talking sience...

Let's make the African elephant unit a standard.

Re:Elephant metric system

[Anonymous Coward]

Even when talking "sience", there's nothing wrong with using pounds and ounces.
This is a US site, and science-savvy Americans understand both systems of units.

Re:Elephant metric system

[Kapiti Kid]

Except that most people in the world, including myself, have no way to relate these medieval measurements to anything meaningful.

Re:Elephant metric system

[drkim]

Sorry Kapiti, that should have read:
"A huge Brachiosaur, once thought to weigh 12597.9 stone, is now believed to have weighed 3621.9 stone."

Re:Elephant metric system

[Onkel Ringelhuth]

> You don't see ten meter-kilograms of torque listed in a technical manual anywhere across the globe, do you?
Nope. The unit is Newton-metres. Now, does anybody want to argue about standardisation of spelling?

Re:Elephant metric system

[KeensMustard]

Actually it's a content driven site, and by the numbers, most of the content is not sourced in the US, and neither are the comments. Who actually cares where it is hosted?

Re:Elephant metric system

[Hognoxious]

Come on mate, how do you think American's translate to kilograms, and vice versa?

Badly, if their use of apostrophes is anything to go by.

Re:Elephant metric system

[hanabal]

Interestingly enough 50,706 pounds is amlost exactly 23,000 Kg. Leading me to believe that the Kg was the original unit of the study

Not necessarily

[Opyros]

This write-up gives reasons for doubting that the new technique does show dinosaurs were significantly lighter than previously thought.

Re:Not necessarily

[wvmarle]

The huge difference in results from this technique and older estimates made me sceptical already.

If one method comes to say 80 tons, and another to say 70 tons, then I say sure, both sound reasonable, and not too far away. But if the other method comes to 23 tons, then I start to wonder what is wrong. One of the methods is wrong for sure, just the question is which one.

Interestingly the article you link to says that the weight of this particular dino was previously estimated at just over 23 tons. Almost exactly what the new method predicts. The 80 ton weight is suggested to be an old figure, and already long since relegated to the history books. The value in the new method is not as much in that the dinos get a lighter weight, it's that it confirms current weight estimates, and will allow for much faster and cheaper measurements on other dino skeletons.

So while your comment is technically correct, it's also slashdot-style suggestive into suggesting that the new technique is wrong, while in fact the new technique confirms the consensus weight of just over 23 tons for the animal. And that would also suggest that current ecosystem calculations are already done with the lighter weight - making the summary even more sensationalist.

Re:Not necessarily

[flyingsquid]

The 80,000 kg estimate has long been thought to be wildly inflated, and that estimate comes from a study published in 1962. A more recent estimate, published in 1997, gave a mass of 31500 for the Berlin brachiosaur, and a study published in 2009 estimated the mass of this specimen at 23000 kg... just 300 kg more than this study. So they haven't actually shaved off much weight with this latest version. It is an interesting new technique, if you have a skeleton to work with. But it's not terribly practical. Only a handful of dinosaurs are complete enough to make skeletal mounts and have actually been mounted. And we already have ways to estimate their mass- either make a model and dunk it in water to figure out the displacement (a method that's been around since the time of Archimedes) or use the diameters of the limb bones to estimate mass (as load-bearing structures, limb bone dimensions are very tightly correlated to total mass). It's nice to see previous estimates verified, and to have some constraints on how much meat to add onto the skeleton, but I don't think this technique is as big an advance as the authors claim.

Accuracy of estimate?

[rossdee]

"A huge Brachiosaur, once thought to weigh 176,370 pounds, is now believed to have weighed 50,706 pounds."

Those figures seem to imply they knew the weight to an accuracy of a few pounds, why don't they 175,000 and 50,000 pounds?

Did they measure the depth of the footprints?

While we are mentioning dinosaurs, a sad farewell to the Author of "A Sound of Thunder" Rest in Peace Ray

Re:Accuracy of estimate?

[quacking duck]

Because the original weights were in kilograms (80,000kg and 23,000kg respectively), and Discovery helpfully converted to the Imperial system for its American audience without properly sourcing the original figures.

Dear discovery channel,

[lurgyman]

When you converted 80,000 kg and 23,000 kg to pounds, it was swell of you to convert 1-2 significant digits to 5. I for one enjoy the round-off noise in the last 3 decimal places - it has premium aesthetic value. I bet those dinos probably thought the same way; losing weight must have been less depressing in terms of losing 2 pounds rather than 0.001%. On second thought, I barely know my own weight to 3 digits...

Re:Dear discovery channel,

[wisnoskij]

Low accuracy and high precision. Now this is a scientific article that has some credibility.

The brachiosaur you write about...

[BlueTak]

Was it a european or an african brachiosaur ? Do you think it could carry coconuts ?

Re:I blame yo-yo dieting myself

[GoodNewsJimDotCom]

Finally scientific evidence comes out saying it is all because of their genetics. We should be ashamed of all the years we've been calling dinosaurs old and fat.

Precision

[Convector]

The masses given equate to 80000 kg and 23000 kg respectively. Or 80 and 23 (metric) tons. Two significant figures. Not more. No doubt those were the numbers originally supplied by the scientists, and the author of TFA converted it to pounds for the typical American reader without understanding how precision works. This happens all the time in the popular press. Clearly you can't estimate the weight of a creature you've never seen to within 1 lb. Your standard human's weight fluctuates by more than that over the course of a day.

Re:Precision

[Anonymous Coward]

"This happens all the time in the popular press. Clearly you can't estimate the weight of a creature you've never seen to within 1 lb"

I went to the museum and saw a big Tyrannosaurus skeleton and I asked the guide how old it was.
He said: "75,000,013 years."
I said: "Wow! Since when do they know the age up to the year?"
He said: "Well, it was 75,000,000 years old when I got this job and that was 13 years ago."

Re:What if they were filled with Hydrogen?

[Culture20]

Wouldn't the buoyancy reduce their weight even more? Really, is there any reason they can't?

And I presume they'd outgas the excess hydrogen as burps which their gizzards (full of flint and iron ore) would ignite?

Re:60s "science"?

[Chris Burke]

Off by a factor of 3 1/2 seems ridiculous, even if we're talking research that was done in the 60s.

I don't think that research was done in the 60s, and I certainly don't think this is up-ending the previous best estimate by such a large factor. I'd bet that guess was made closer to the time Brachiasaurus was discovered in the very early 1900s, and that's why it says "once thought" and "estimates have been as high".

WP suggests the most recent estimate (from 2009) was 28.7 metric tonnes.

While this new figure is still appreciably lighter, it doesn't make it sound as shocking to use the most recent estimate as the comparison point, does it?

Re:And geeks wonder why Joe Six-pack disbelieves..

[Chris Burke]

10/10 for using the ol' "science is like Religion because they claim to have Truth and banish those who disagree with their Orthodoxy" line in an article about scientists at a major research university up-ending the "orthodoxy" and publishing their "heresey" in a Royal Society publication. I love this kind of irony.

Re:And geeks wonder why Joe Six-pack disbelieves..

[Anonymous Coward]

What's so wrong with a changing belief anyway? Why this fixation on having an unchanging and un-adaptable view of the world?

I've changed a lot since I was born. My home town has too (though not as much some other places!). Very little in nature stays the same over a lifetime; rivers get different flow paths; lizards stop laying eggs and go placental. How I knew the world to work when I was seven is very different to how I knew the world to work at age 21 or how I know the world works at age 35. Things I knew to be true in the past turn out to be wrong or incomplete, and no doubt some of the things I hold to be absolute in my life now will turn out to be less than that in the future.

So why is it so bloody bad that theories and scientific understandings of the world change over time? Why do those choose to believe in system they profess hasn't changed in 2000 years (even though it clearly has changed and is still changing) get to be all "AHH! I CAUGHT YOU!" every time science discovers something that changes our view of the world? All modern science is built on the idea of falsifying the results of others, so off course some things are going to be found to be not true. All good scientists should be able to say "of course, I could be wrong - and this is how". AND THIS IS A GOOD THING.

I don't see many religious people willing to say that same thing... and I would guess that's why they feel it is so incompatible with their world view.

A view of the world that claims to be unchanging and immovable is clearly lying, and is clearly a faulty and unnatural way to be. It is for that reason that it should be expunged from the system.

Re:overblown as usual

[FrootLoops]

I hate it when people deride dark matter without having the first clue about it. Neutrinos interact only through the weak force and gravity. Maybe another particle interacts only through gravity. No EM emissions would make it dark, no strong or weak interactions would make it essentially undetectable on earth. It would only show up on astronomical scales. Oh, and humans (who are very biased towards the types of particles we're made of and interact regularly with) would think the whole thing was voodoo.

And maybe not. There are numerous explanations for dark matter ranging from various forms of exotic matter to fundamental problems with existing theory. So far there are no clear winners. Making a "mathematical error vs. magical substance" dichotomy is so oversimplified it would be better for you to simply be quiet on this topic.

Re:I blame yo-yo dieting myself

[flyneye]

"Discovery.com has an article on a new study"

The problem with the gullibility of the world are those willing to swallow that a "study" constitutes research bearing evidence.
Bad news, Jim, the study, is a quicky look at an information set for the purpose of determining if further research ( an actual search for evidence) is worth throwing money at. A strange animal , the study, frequently found near bored professors trying to busy a classroom has also been sited being unethically molested by corporations and governments for the purpose of manipulating the populace into beliefs advantageous to their purposes. This modern "study" device is actually descended from a useful tool that used to be defined by rules designed to make it scientifically useful; like polling a random 10% of your info pool, remaining an unbiased observer and including findings that may be contrary to the benefactors goal. Compare and contrast to todays "study" used to sell you everything from soap to political party, Polling targeted groups, interacting to manipulate outcomes and of course only keeping what could be construed as useful to a benefactors cause.

Caveat Geekor!