[Swordmaker]

A California condor (290 cm) is 25 times larger than a chestnut sparrow (11.4 cm). If we scale up a Chestnut Sparrow (13.4 g) to the size of a California Condor using the formula in your illustration, the sparrow would weigh more than 200 kg.

Interesting argument... but wrong.

The failing in your comparison is that the body structure of your Chestnut sparrow is not the same as a California Condor. You're basing your 25 times scaling on Wing span... not body length and breadth, where the bulk of a bird's mass is concentrated.

As I have indicated by frequent statement, the proportions need to be close to identical in the comparisons.

Your Chestnut Sparrow has a wingspan about equal to its body length including tail feathers... that's a 1 to 1 ratio or around a 4.5" wingspan.

The California Condor - like the Teratorn - has a wingspan that is ~3.5 times its body length including tail. The Teratorns and the Condors share similar structure with wing span to body length ratio of about 3.5 to 1.

The short, stubby, flapping wings of the Chestnut sparrow are not in the same proportion to its body length and breadth as the long gliding wings of the Condor and Teratorns to their body length and breadth.

Chestnut Sparrow
Cute little fellow, isn't he?

California Condor
Ugly fellow, isn't he?


Raptor proportions
California Condor is at the top.

The teratorn body is simply a proportionately scaled up version of an eagle or condor... but your Chestnut Sparrow scaled up to equal the wing span of the California Condor, and all other body parts scaled by the same multiplier, would have a body 9.375 feet long and would not be able to fly either... because he WOULD have the weight you calculated.

Let's do it properly and calculate the body mass of your scaled up sparrow using only the body length, which as mentioned above is where the vast majority of the weight of a bird is concentrated.

The body length of an average California Condor including tail feathers is ~45"... so, ~45" divided by ~4.5" (body length of your C. Sparrow) gives us a multiplier of ~10 times... the calculated weight of the ~10 times larger C. Sparrow would be ~10³ = ~1,000 x ~13.4g = ~13,400g = ~13.4Kg = ~29.5 Lbs.

Whow... what do you know... while a little heavy for an average Condor (which is probably because the C. Sparrow is considered a "chunky" bird for its size), it's right in the range of California Condor weights reported by the National Geographic's California Condor web page.

[valkyry1]

I caught that right away also. His using of a sparrow as a model compared to the Condor and the Teratorn was so absurd that most likely he is totally ignorant in these areas of knowledge. Or maybe much less likely he had some coaching and used that example in an attempt to mix things up.

[js1138]

As long as we are discussing which dimensions are to be used in your formula, you might want to explain how much tail feathers contribute to body mass, and why you included their length, while rejecting wingspan. Just curious. The only objects that scale correctly with your formula are spheres and polyhedrons that can be mathematically approximated by spheres.

I showed you and extreme example of how simple measurements don’t scale up. Now it is your turn to show the exact measurements used to calculate the body mass of dinosaurs. let’s see the actual calculations.

As to whether teratorns could fly, your calculations of energy requirements are rubbish. Gliding birds may require a significant amount of headwind in order to take off, but once aloft, they seldom flap. Some are not able to take off at all without a headwind.

This leaves unanswered the question of how much time the largest teratorns may have spent flying, and whether flying was a significant component of their hunting.

All these speculations are interesting,, but they hardly add up to evidence to overthrow two centuries of physics.