Slashdot Mirror

← Back to Stories (view on slashdot.org)

New Analysis Shows Dinosaurs Not As Heavy As Previously Believed.

Posted by samzenpus on from the he's-not-heavy-he's-my-dinosaur dept.

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."

4 of 155 comments (clear)

  1. What about footprints? by fotoguzzi · · Score: 5, Interesting

    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.]

    --
    Their they're doing there hair.
  2. 60s "science"? by Gordo_1 · · Score: 1, Interesting

    Even without computer simulations, I imagine they'd compare dinosaur skeletons to that of elephants, horses, giraffes, rhinos and even birds (which are supposed to be descended from the dinosaurs) to develop some reasonable bone mass or skeletal girth to weight ratios, no? Off by a factor of 3 1/2 seems ridiculous, even if we're talking research that was done in the 60s.

    And in response to myself... According to the article (which I just skimmed), a common method was to take an artist’s reconstruction sculpture of the animal, measure its volume and multiply by the density to get its weight.

    So rather than using animals we know as a guideline and performing some basic math, they let an artiste eyeball it by building some completely arbitrary model that happened to envelop the skeleton and then used that model as a guide to dinosaur weight, which in turn had sweeping impacts on virtually every aspect of our understanding of dinosaurs.

    And you wonder why people don't trust science...

    1. Re:60s "science"? by Anonymous Coward · · Score: 2, Interesting

      It's not ridiculous, because: A) reconstructing skeletons is challenging enough (look at the historical changes in understanding of the posture of dinosaur hips), B) reconstructing muscle mass, bone internal structure/density, lung volume, etc. is even more challenging, and C) the 80 tonnes estimate for Brachiosaurus was an upper limit, not the median estimate (which was closer to 40 or 50 tonnes). Being off by a factor of 2-3x is not ridiculous given the significant uncertainties, and you can't blame artists for it. They rendered the soft tissues of the models as specified by the scientists.

      It took years before there was a better understanding of dinosaur anatomy. Take a look at reconstructions from the 1960s or 1970s versus more recent ones, and that explains most of the change. These "lighter dinosaur" models have been showing up in the last 10 years or so as 3D computer modeling techniques have improved (that 80 tonnes estimate is decades old), so this change isn't really news either. A few papers were already challenging the old numbers a few years ago. And if you fault the older estimates, well, you have to start with something. It's the normal process of refinement in science as techniques improve.

  3. Re:Elephant metric system by hanabal · · Score: 4, Interesting

    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