Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site psivax.UUCP Path: utzoo!watmath!clyde!burl!ulysses!gamma!epsilon!zeta!sabre!petrus!bellcore!decvax!tektronix!hplabs!sdcrdcf!psivax!friesen From: friesen@psivax.UUCP (Stanley Friesen) Newsgroups: net.origins Subject: Re: more on 250 lb. birds Message-ID: <687@psivax.UUCP> Date: Wed, 28-Aug-85 16:00:14 EDT Article-I.D.: psivax.687 Posted: Wed Aug 28 16:00:14 1985 Date-Received: Mon, 2-Sep-85 03:33:28 EDT References: <375@imsvax.UUCP> Reply-To: friesen@psivax.UUCP (Stanley Friesen) Organization: Pacesetter Systems Inc., Sylmar, CA Lines: 99 Summary: In article <375@imsvax.UUCP> ted@imsvax.UUCP (Ted Holden) writes: > > 1. A 200 lb. bird could not possibly fly in our world, for > reasons having to do with power to weight ratios. Don't > take my word for this. You reside in a major university > with physics and engineering departments. Have them do the > calculations. > And when they do it is *you* who will be surprised. Yes power to weight ratios are important, but power problems can always be solved by building a larger power plant - i.e adding more muscle. I suspect that any "calculations" which say that the Pteratorn (Greek for Wingbird) coudln't fly were based on simple proportional scaling from the largest existing eagles. The correct procedure is to produce a allometric equation relating body size and muscle mass in eagles and extend it up to the size of the Pteratorn. The results are almost certain to be that it *could* fly. In fact the extra ~100 lbs in the higher weight estimate may be just such a correction! Remember the same physics controls airplane flight as bird flight, and we build perfectly good airplanes that weigh many *tons*, it is just a matter of supplying enough power. > 1.1 Consider ...the Pteratorn was a bird equivalant of an F16, > his wings being made for aerial maneuver, swooping, and > pouncing. How much more impossible his life! The biggest > Berkuts, by the way, vary their weight from 22 to 26 lbs or > so; at 22 lbs, they fly and kill things, at 26 lbs they sit > around feeling fat and happy and wait until they get back > down to 22 or so to fly some more. > A large part of the reason that a 26 lb berkut Eagle cannot fly is that the extra poundage *is* fat, not muscle. Its flight apparatus is powered for a weight of 22 lbs. This is like putting a trunk full of lead in a piper cub and expecting it to fly! Yet an airplane with a larger powerplant will easily lift a trunk of lead! In other words, the difficulty which the heaviest Berkuts have with flying is *irrelevant* to wether a Pteratorn could fly. > 3. Brontasaurs and Ultrasaurs, in all likelihood, could not > even walk in our world. Every book on dinosaurs I have ever > read in which the author did any thinking, makes some > mention of this problem. Most claim that the brontosaur > lived in water, since his legs would not easily support his > great bulk on land. But the brontasaur, if water based, > would have needed huge flat feet to keep from sinking > hopelessly in the mud on river bottoms and floundering. He > didn't have them. > Again, totally incorrect. The myth that these animals could not support themselves on land was *never* supported by valid calculations. It originated because the first fossils of this sort of dinosaur were thought to be the reptilian equivalent of whales(since no leg bones were found in the original find) - it was called Cetiosaurus, meaning Whale Lizard. Then the leading palaeontologists looked at these beast and said "I do not believe they could walk on land at that size" and everyone believed them - without checking it out. When we finally got around to actually performing the necessary calculations the results were that the skeletons of these animals were *completely* capable of supporting them on land, in fact they had the normal amount of safety margin for large land animals. Try reading some of Colbert's later books on dinosaurs, or look at some recent articles on the subject in journals. The latest weight calculation was, I believe, in a recent of the Linnaean Society Zoological Journal. > 4. The ultrasaur is a relatively new find. Much larger than > the brontasaur, he will not likely appear in standard > dinosaur books. >> A lot of Gee Whiz stuf of no real relevance deleted > Weight would be a far worse problem > for the ultrasaur than the brontasuar. There is no reason to suppose that the Ultrasaur(nor even the Supersaur - another new "brontosaur") would have had any less of a safety margin than any other Sauropod dinosaur. > > 5. The only logical explanation for these impossible animals is > that the felt effect of the force of gravity was less in the > archaic world than it is now. Actually, the only logical explanation is that you are hopelessly out of date with your facts. > > 6. Consider the one place on this earth where really big > animals are found today, namely the oceans. There also, due > to the effect of water bouyancy, the felt effect of gravity > is less than what we experience. Funny coincidence, isn't > it. Hmm, well not exactly a coincidence. But the larger whales are *many* times larger than the largest Sauropod. Also there is more food available in the oceans, so that might also have something to do with it! -- Sarima (Stanley Friesen) UUCP: {ttidca|ihnp4|sdcrdcf|quad1|nrcvax|bellcore|logico}!psivax!friesen ARPA: ttidca!psivax!friesen@rand-unix.arpa