by Ted Holden
Note by cadxx: Ted Holden was a hero of mine and many others in the early days of the Internet although for some reason we never communicated. He must have just finished his stint on TalkOrigins when I did my own, maybe for two years, arguing for scientific sanity among the true believers, medieval monks and the just plain brainwashed. Impossible dinosaurs was probably written sometime in the 1990’s and as far as I can tell originated here: http://www.kronia.com/symposium/holden.txt now defunked.
The Impossible Dinosaurs – Megafauna and Attenuated Gravity
by Ted Holden
Reblogged from http://www.freerepublic.com/focus/chat/1989265/posts
Posted on 21/03/2008, 09:01:20 by Swordmaker
It is a fairly easy demonstration that nothing any larger than the largest elephants could live in our world today, and that the largest dinosaurs survived ONLY because the nature of the world and of the solar system was then such that they did not experience gravity as we do at all; they’d be crushed by their own weight, collapse in a heap, and suffocate within minutes were they to.
A look at sauropod dinosaurs as we know them today requires that we relegate the brontosaur, once thought to be one of the largest sauropods, to welterweight or at most middleweight status. Fossil finds dating from the 1970’s dwarf him. The Avon field Guide to Dinosaurs shows a brachiosaur (larger than a brontosaur), a supersaur, and an ultrasaur juxtaposed, and the ultrasaur dwarfs the others. Christopher McGowan’s “DINOSAURS, SPITFIRES, & SEA DRAGONS”, Harvard, 1991 cites a 180 ton weight estimate for the ultrasaur (page 118), and (page 104) describes the volume-based methods of estimating dinosaur weights. McGowan is Curator of Vertebrate Paleontology at the Royal Ontario Museum.
This same look requires that dinosaur lifting requirements be compared to human lifting capabilities. One objection which might be raised to this would be that animal muscle tissue was somehow “better” than that of humans. This, however, is known not to be the case; for instance, from Knut Nielson’s, “Scaling, Why is Animal size So Important”, Cambridge Univ Press, 1984, page 163, we have:
“It appears that the maximum force or stress that can be exerted by any muscle is inherent in the structure of the muscle filaments. The maximum force is roughly 4 to 4 kgf/cm2 cross section of muscle (300 – 400 kN/m2). This force is body-size independent and is the same for mouse and elephant muscle. The reason for this uniformity is that the dimensions of the thick and thin muscle filaments, and also the number of cross-bridges between them are the same. In fact the structure of mouse muscle and elephant muscle is so similar that a microscopist would have difficulty identifying them except for a larger number of mitrochondria in the smaller animal. This uniformity in maximum force holds not only for higher vertebrates, but for many other organisms, including at least some, but not all invertebrates.”
Another objection might be that sauropods were aquatic creatures. Nobody believes that anymore; they had no adaptation for aquatic life, their teeth show wear and tear which does not come from eating soft aquatic vegetation, and trackways show them walking on land with no difficulty.
A final objection would be that dinosaurs were somehow more “efficient” than top human athletes, or had better “leverage”. Superposed images of sauropods and powerlifters at roughly equal-weight sizes show the sauropod’s legs to be puny compared to the human athletes’, as one would expect, since the sauropod’s body was mostly digestive system, the humans’s mostly muscle. The better-leverage argument would require the sauropod to be a spectacularly knob-kneed sort of a creature whose knees and other joints were wider than those of the human athletes, even though the rest of their legs were spindly by contrast with the humans. A quick look at the pictures dispels this.
By “scaled lift”, I mean of course a lift record divided by the two-thirds power of the athlete’s body weight. As creatures get larger, weight, which is proportional to volume, goes up in proportion to the cube of the increase in dimension. Strength, on the other hand, is known to be roughly proportional to cross section of muscle for any particular limb, and goes up in proportion to the square of the increase in dimension. This is the familiar “square-cube” problem. The normal inverse operator for this is to simply divide by [the] 2/3 power of body weight, and this is indeed the normal scaling factor for all weight lifting events, i.e. it lets us tell if a 200 lb. athlete has actually done a “better” lift than the champion of the 180 lb. group. For athletes roughly between 160 and 220 lbs, i.e. whose bodies are fairly similar, these scaled lift numbers line up very nicely. It is then fairly easily seen that a lift for a scaled up version of one particular athlete can be computed via this formula, since the similarity will be perfect, scaling being the only difference.
Consider the case of Bill Kazmaier, the king of the power lifters in the seventies and eighties. Power lifters are, in the author’s estimation, the strongest of all athletes; they concentrate on the three most difficult total-body lifts, i.e. benchpress, squat, and dead-lift. They work out many hours a day and, it is fairly common knowledge, use food to flavor their anabolic steroids with. No animal the same weight as one of these men could be presumed to be as strong. Kazmaier was able to do squats and dead lifts with weights between 1000 and 1100 lb. on a bar, assuming he was fully warmed up.
Standing Up at 70,000 lb.
Any animal has to be able to lift its own weight off the ground, i.e. stand up, with no more difficulty than Kazmaier experiences doing a 1000 lb. squat. Consider, however, what would happen to Mr. Kazmaier, were he to be scaled up to 70,000 lb., the weight commonly given for the brontosaur. Kazmaier’s maximum effort at standing, fully warmed up, assuming the 1000 lb. squat, was 1340 lb. (1000 for the bar and 340 for himself). The scaled maximum lift would be a solution to:
1340/340.667 = x/70,000.667 or 47,558 lb..
He’d not be able to lift his weight off the ground!
A sauropod dinosaur had four legs you might say; what happens if Mr. Kazmaier uses arms AND legs at 70,000 lb.. The truth is that the squat uses almost every muscle in the athlete’s body very nearly to the limits, but in this case, it doesn’t even matter. A near maximum benchpress effort for Mr. Kazmaier would fall around 600 lb.. This merely changes the 1340 to 1940 in the equation above, and the answer comes out as 68,853. Even using all muscles, some more than once, the strongest man who we know anything about would not be able to lift his own weight off the ground at 70,000 lb.!
Moreover, Kazmaier is using glutteal and lower back muscles in the squat, and pectorals in the benchpress, i.e. extra muscle groups which the sauropod he is being compared to would not be assisted by in standing. Any tiny advantage in leverage which a sauropod might have over the human lifter for any reason, would be overwhelmed by the huge edge in available musculature and the usage of the extra muscle groups on the part of the human in the comparison.
To believe then, that a brontosaur could stand at 70,000 lb., one has to believe that a creature whose weight was largely gut and the vast digestive mechanism involved in processing huge amounts of low-value foodstuffs, was somehow stronger than a creature its size which was almost entirely muscle, and that far better trained and conditioned than would ever be found amongst grazing animals. That is not only ludicrous in the case of the brontosaur, but the calculations only get worse when you begin trying to scale upwards to the supersaur and ultrasaur at their sizes.
How heavy can an animal still get to be in our world, then? How heavy would Mr. Kazmaier be at the point at which the square-cube problem made it as difficult for him just to stand up as it is for him to do 1000 lb. squats at his present size of 340 lb.? The answer is simply the solution to:
1340/340.667 = x/x.667
or just under 21,000 lb.. In reality, elephants do not appear to get quite to that point. McGowan (DINOSAURS, SPITFIRES, & SEA DRAGONS, p. 97) claims that a Toronto Zoo specimen was the largest in North America at 14,300 lb., and Smithsonian personnel once informed the author that the gigantic bush elephant specimen which appears at their Museum of Natural History weighed around 8 tons.
Again, in all cases, we are comparing the absolute max effort for a human weight lifter to lift and hold something for two seconds versus the sauropod’s requirement to move around and walk all day long with scaled weight greater than these weights involved in the maximum, one-shot, two-second effort. That just can’t happen.
Sauropod Dinosaurs’ Necks
A second category of evidence for attenuated felt effect of gravity in antediluvian times arises from the study of sauropod dinosaurs’ necks. Scientists who study sauropod dinosaurs are now claiming that they held their heads low, because they could not have gotten blood to their brains had they held them high. McGowan (again, DINOSAURS, SPITFIRES, & SEA DRAGONS) goes into this in detail (pages 101 – 120). He mentions the fact that a giraffe’s blood pressure, at 200 – 300 mm Hg, far higher than that of any other animal, would probably rupture the vascular system of any other animal, and is maintained by thick arterial walls and by a very tight skin which apparently acts like a jet pilot’s pressure suit. A giraffe’s head might reach to 20′. How a sauropod might have gotten blood to its brain at 50′ or 60′ is the real question.
Two articles which mention this problem appeared in the 12/91 issue of Natural History. In “Sauropods and Gravity”, Harvey B. Lillywhite of Univ. Fla., Gainesville, notes:
“…in a Barosaurus with its head held high, the heart had to work against a gravitational pressure of about 590 mm of mercury (Hg). In order for the heart to eject blood into the arteries of the neck, its pressure must exceed that of the blood pushing against the opposite side of the outflow valve. Moreover, some additional pressure would have been needed to overcome the resistance of smaller vessels within the head for blood flow to meet the requirements for brain and facial tissues. Therefore, hearts of Barosaurus must have generated pressures at least six times greater than those of humans and three to four times greater than those of giraffes.”
In the same issue of Natural History, Peter Dodson (“Lifestyles of the Huge and Famous”), mentions that:
“Brachiosaurus was built like a giraffe and may have fed like one. But most sauropods were built quite differently. At the base of the neck, a sauropod’s vertebral spines unlike those of a giraffe, were weak and low and did not provide leverage for the muscles required to elevate the head in a high position. Furthermore, the blood pressure required to pump blood up to the brain, thirty or more feet in the air, would have placed extraordinary demands on the heart (see opposite page) [Lillywhite’s article] and would seemingly have placed the animal at severe risk of a stroke, an aneurysm, or some other circulatory disaster. If sauropods fed with the neck extended just a little above heart level, say from ground level up to fifteen feet, the blood pressure required would have been far more reasonable.”
Dodson is neglecting what appears to be a dilemma in the case of the brachiosaur, but there are at least two far greater dilemmas here. One is that the good leaves were, in all likelihood, above the 20′ mark; holding his head out at 20′, an ultrasaur would, in all likelihood, starve.
Moreover, it turns out that a problem every bit as bad or worse than the blood pressure problem would arise, perceived gravity being what it is now, were sauropods to hold their heads out just above horizontally as Dodson and others are suggesting. Try holding your arm out horizontally for more than a minute or two, and then imagine your arm being 40′ long and 30,000 lb……
An ultrasaur or seismosaur with a neck 40′ – 60′ long and weighing 25000 – 40000 lb., would be looking at 400,000 to nearly a million foot pounds of torque were one of them to try to hold his neck out horizontally. That’s crazy. You don’t hang a 30,000 lb load 40′ off into space even if it is made out of wood and structural materials, much less flesh and blood. No building inspector in America could be bribed sufficiently to let you build such a thing.
In fact, a cursory look at an Elephant’s skeleton reveals a structural system much like Roman archicture with one and only one purpose in mind, i.e. bearing the elephant’s great weight. The legs are columns and the spine is a Roman arch. A sauropod’s neck, however, particularly in the case of the recent ultrasaur and seismosaur finds, weighed several times the weight of a large elephant and, if held outwards horizontally, would actually arch downwards (the wrong way). Reconstructions actually depict them like that, no thought whatever having been taken as to the consequences, either by the scientists or the artists involved.
And so, sauropods (in our gravity) couldn’t hold their heads up, and they couldn’t hold them out either. That doesn’t leave much.
Antediluvian Flying Creatures
A third category of evidence for attenuated felt effect of gravity in antediluvian times arises from studies of creatures which flew in those times, and of creatures which fly now.
In the antediluvian world, 350 lb flying creatures soared in skies which no longer permit flying creatures above 30 lb. or so. Modern birds of prey (the Argentinean teratorn) weighing 170 -200 lb. with wingspans of 30′ also flew; within recorded history, central Asians have been trying to breed hunting eagles for size and strength, and have not gotten them beyond 25 lb. or thereabouts. At that point they are able to take off only with the greatest difficulty. Something was vastly different in the pre-flood world.
Nothing much larger than 30 lb. or so flies anymore, and those creatures, albatrosses and a few of the largest condors and eagles, are marginal. Albatrosses in particular are called “gooney birds” by sailors because of the extreme difficulty they experience taking off and landing, their landings being (badly) controlled crashes, and all of this despite long wings made for maximum lift.
The felt effect of the force of gravity on earth was much less in remote times, and only this allowed such giant creatures to fly. No flying creature has since RE-EVOLVED into anything like former sizes, and the one or two birds which have retained such sizes have forfeited any thought of flight, their wings becoming vestigial.
A book of interest here is Adrian Desmond’s “The Hot Blooded Dinosaurs. Desmond has a good deal to say about the pteranodon, the 40 – 50 lb. pterosaur which scientists used to believe to be the largest creature which ever flew:
“Pteranodon had lost its teeth, tail and some flight musculature, and its rear legs had become spindly. It was, however, in the actual bones that the greatest reduction of weight was achieved. The wing bones, backbone and hind limbs were tubular, like the supporting struts of an aircraft, which allows for strength yet cuts down on weight. In Pteranodon these bones, although up to an inch in diameter, were no more than cylindrical air spaces bounded by an outer bony casing no thicker than a piece of card. Barnum Brown of the American Museum reported an armbone fragment of an unknown species of pterosaur from the Upper Cretaceous of Texas in which ‘the culmination of the pterosaur… the acme of light construction’ was achieved. Here, the trend had continued so far that the bone wall of the cylinder was an unbelievable one-fiftieth of an inch thick Inside the tubes bony crosswise struts no thicker than pins helped to strengthen the structure, another innovation in aircraft design anticipated by the Mesozoic pterosaurs.
The combination of great size and negligible weight must necessarily have resulted in some fragility. It is easy to imagine that the paper-thin tubular bones supporting the gigantic wings would have made landing dangerous. How could the creature have alighted without shattering all of its bones How could it have taken off in the first place It was obviously unable to flap twelve-foot wings strung between straw-thin tubes. Many larger birds have to achieve a certain speed by running and flapping before they can take off and others have to produce a wing beat speed approaching hovering in order to rise. To achieve hovering with a twenty-three foot wingspread, Pteranodon would have required 220 lb. of flight muscles as efficient as those in humming birds. But it had reduced its musculature to about 8 lb., so it is inconceivable that Pteranodon could have taken off actively.
Pteranodon, then, was not a flapping creature, it had neither the muscles nor the resistance to the resulting stress. Its long, thin albatross-like wings betray it as a glider, the most advanced glider the animal kingdom has produced. With a weight of only 40 lb. the wing loading was only I lb. per square foot. This gave it a slower sinking speed than even a man-made glider, where the wings have to sustain a weight of at least 4 lb. per square foot. The ratio of wing area to total weight in Pteranodon is only surpassed in some of the insects. Pteranodon was constructed as a glider, with the breastbone, shoulder girdle and backbone welded into a box-like rigid fuselage, able to absorb the strain from the giant wings. The low weight combined with an enormous wing span meant that Pteranodon could glide at ultra-low speeds without fear of stalling. Cherrie Bramwell of Reading University has calculated that it could remain aloft at only 15 m.p.h. So takeoff would have been relatively easy. All Pteranodon needed was a breeze of 15 m.p.h. when it would face the wind, stretch its wings and be lifted into the air like a piece of paper. No effort at all would have been required. Again, if it was forced to land on the sea, it had only to extend its wings to catch the wind in order to raise itself gently out of the water. It seems strange that an animal that had gone to such great lengths to reduce its weight to a minimum should have evolved an elongated bony crest on its skull.”
Desmond has mentioned some of the problems which even the pteranodon faced at fifty lb. or so; no possibility of flapping the wings for instance. The giant teratorn finds of Argentina were not known when the book was written… they came out in the eighties in issues of Science Magazine and other places.
Teratorn – Giant Eagles that lived up to about 12,000 years ago.
The terotorn was a 160 – 200 lb eagle with a 27′ wingspan, a modern bird whose existence involved flapping wings, aerial maneuver etc. How so? There are a couple of other problems which Desmond does not mention, including the fact that life for a pure glider would be almost impossible in the real world, and that some limited flying ability would be necessary for any aerial creature. Living totally at the mercy of the winds, a creature might never get back home to its nest and children given the first contrary wind.
There is one other problem. Desmond notes a fairly reasonably modus operandi for the pteranodon, i.e. that it had a throat pouch like a pelican, has been found with fish fossils indicating a pelican-like existence, soaring over the waves and snapping up fish without landing. That should indicate that, peculiarly amongst all of the creatures of the earth, the pteranodon should have been practically IMMUNE from the great extinctions of past ages. Velikovsky noted that large animals had the greatest difficulty getting to high ground and other safe havens at the times of floods and the global catastrophes of past ages and were therefore peculiarly susceptible to extinction. Ovid notes (Metamorphoses) that men and animals hid on mountain tops during the deluge, but that most died from lack of food during the hard year following. But high places safe from flooding were always there; oceans were always there and fish were always there. The pteranodon’s way of life should have been impervious to all mishap; the notion that pteranodon died out when the felt effect of gravity on earth changed after the flood is the only good explanation.
Back to Adrian Desmond for more on size as related to pterosaurs now:
“It would be a grave understatement to say that, as a flying creature, Pteranodon was large. Indeed, there were sound reasons for believing that it was the largest animal that ever could become airborne. With each increase in size, and therefore also weight, a flying animal needs a concomitant increase in power (to beat the wings in a flapper and to hold and maneuver them in a glider), but power is supplied by muscles which themselves add still more weight to the structure.– The larger a flyer becomes the disproportionately weightier it grows by the addition of its own power supply. There comes a point when the weight is just too great to permit the machine to remain airborne. Calculations bearing on size and power suggested that the maximum weight that a flying vertebrate can attain is about 50 lb.: Pteranodon and its slightly larger but lesser known Jordanian ally Titanopteryx were therefore thought to be the largest flying animals.”
Notice that the calculations mentioned say about 50 lb. is max for either a flier or a glider, and that experience from our present world absolutely coincides with this and, in fact, don’t go quite that high; the biggest flying creatures which we actually see are albatrosses, geese etc. at around 30 – 35 lb.. Similarly, my calculations say that about 20000 lb. would be the largest theoretically possible land animal in our present world, and Jumbo the stuffed elephant which I’ve mentioned, the largest known land animal from our present world, was around 16000.
“But in 1972 the first of a spectacular series of finds suggested that we must drastically rethink our ideas on the maximum size permissible in flying – vertebrates. Although excavations are still in progress, three seasons’ digging – from 1972 to 1974 – by Douglas A. Lawson of the University of California has revealed partial skeletons of three ultra-large pterosaurs in the Big Bend National Park in Brewster County, Texas These skeletons indicate creatures that must have dwarfed even Pteranodon. Lawson found the remains off four wings, a long neck, hind legs and toothless jaws in deposits that were non-marine; the ancient entombing sediments are thought to have been made instead by floodplain silting. The immense size of the Big Bend pterosaurs, which have already become known affectionately in the palaeontological world as ‘747s’ or ‘Jumbos’, may be gauged by setting one of the Texas upper arm bones alongside that of a Pteranodon: the ‘Jumbo’ humerus is fully twice the length of Pteranodon’s. Lawson’s computer estimated wingspan for this living glider is over fifty feet It is no surprise, says Lawson announcing the animal in Science in 1975, that the definitive remains of this creature were found in Texas.
Unlike Pteranodon, these creatures were found in rocks that were formed 250 miles inland of the Cretaceous coastline. The lack of even lake deposits in the vicinity militates against these particular pterosaurs having been fishers. Lawson suggests that they were carrion feeders, gorging themselves on the rotting mounds of flesh left after the dismembering of a dinosaur carcass. Perhaps, like vultures and condors, these pterosaurs hung in the air over the corpse waiting their turn. Having alighted on the carcass, their toothless beaks would have restricted them to feeding upon the soft, pulpy internal organs. How they could have taken to the air after gorging themselves is something of a puzzle. Wings of such an extraordinary size could not have been flapped when the animal was grounded. Since the pterosaurs were unable to run in order to launch themselves they must have taken off vertically. Pigeons are only able to takeoff vertically by reclining their bodies and clapping the wings in front of them; as flappers, the Texas pterosaurs would have needed very tall stilt-like legs to raise the body enough to allow the 24-foot wings to clear the ground The main objection, however, still rests in the lack of adequate musculature for such an operation. Is the only solution to suppose that, with wings fully extended and elevators raised, they were lifted passively off the ground by the wind? If Lawson is correct and the Texas pterosaurs were carrion feeders another problem is envisaged. Dinosaur carcasses imply the presence of dinosaurs. The ungainly Brobdignagian pterosaurs were vulnerable to attack when grounded, so how did they escape the formidable dinosaurs? Left at the mercy of wind currents, takeoff would have been a chancy business. Lawson’s exotic pterosaurs raise some intriguing questions. Only continued research will provide the answers.”
Note that Desmond mentions a number of ancillary problems, any of which would throw doubt on the pterosaur’s ability to exist as mentioned, and neglects the biggest question of all: the calculations which say 50 lb. are max have not been shown to be in error; we have simply discovered larger creatures. Much larger. This is what is called a dilemma.
Then I come to what Robert T. Bakker has to say about the Texas Pterosaurs (“The Dinosaur heresies”, Zebra Books, pp 290-291:
“Immediately after their paper came out in Science, Wann Langston and his students were attacked by aeronautical engineers who simply could not believe that the big Bend dragon had a wingspan of forty feet or more. Such dimensions broke all the rules of flight engineering; a creature that large would have broken its arm bones if it tried to fly… Under this hail of disbelief, Langston and his crew backed off somewhat. Since the complete wing bones hadn’t been discovered, it was possible to reconstruct the Big Bend Pterodactyl [pterosaur] with wings much shorter than fifty feet.”
The original reconstruction had put wingspan for the pterosaur at over 60′. Bakker goes on to say that he believes the pterosaurs really were that big and that they simply flew despite our not comprehending how, i.e. that the problem is ours. He does not give a solution as to what we’re looking at the wrong way.
So much for the idea of anything RE-EVOLVING into the sizes of the flying creatures of the antedeluvian world. What about the possibility of man BREEDING something like a teratorn? Could man actively breed even a 50 lb. eagle?
David Bruce’s “Bird of Jove”, Ballentine Books, 1971, describes the adventures of Sam Barnes, one of England’s top falconers at the time, who actually brought a Berkut eagle out of Kirghiz country to his home in Pwllheli, Wales. Berkuts are the biggest eagles, and Atlanta, the particular eagle which Barnes brought back, at 26 lb. in flying trim, is believed to be as large as they ever get. These, as Khan Chalsan explained to Barnes, have been bred specifically for size and ferocity for many centuries. They are the most prized of all possessions amongst nomads, and are the imperial hunting bird of the turko-mongol peoples.
The eagle Barnes brought back had a disease for which no cure was available in Kirghiz, and was near to death then, otherwise there would have been no question of his having her. Chalsan explained that a Berkut of Atlanta’s size would normally be worth more than a dozen of the most beautiful women in his country.
The killing powers of a big eagle are out of proportion to its size. Berkuts are normally flown at wolves, deer, and other large prey. Barnes witnessed Atlanta killing a deer in Kirghiz, and Chalsan told him of her killing a black wolf a season earlier. Mongols and other nomads raise sheep and goats, and obviously have no love for wolves. A wolf might be little more than a day at the office for Atlanta with her 11″ talons, however, a wolf is a major-league deal for an average sized Berkut at 15 – 20 lb.. Chalsan explained that wolves occasionally win these battles, and that he had once seen a wolf kill three of the birds before the fourth killed him. Quite obviously, there would be an advantage to having the birds be bigger, i.e. to having the average berkut be 25 lb., and a big one be 40 or 50.
It has never been done, however, despite all of the efforts since the days of Chengis Khan. We have Chengis Khan’s famous “What is best in life…” quote, and the typical Mongol reply from one of his captains involved falconry. They regarded it as important. Chengis Khan, Oktai, Kuyuk, Hulagu, Batui, Monke, Kubilai et. al. were all into this sport big time, they all wanted these birds big, since they flew them at everything from wolves and deer (a big berkut like Atlanta can drive its talons in around a wolf’s spine and snap it) to leopards and tigers, and there was no lack of funds for the breeding program involved. Chengis Khan did not suffer from poverty.
Moreover, the breeding of berkuts has continued apace from that day to this, including a 200 year stretch during which those people ruled almost all of the world which you’d care to own at the time, and they never got them any bigger than 25 lb. or so.
Remember Desmond’s words regarding the difficulty which increasingly larger birds will experience getting airborne from flat ground? Atlanta was powerful enough in flight, but she was not easily able to take off from flat ground. Barnes noted one instance in which a town crank attacked Atlanta with a cane and the great bird had to frantically run until it found a sand dune from which to launch herself. This could mean disaster in the wild. A bird of prey will often come to ground with prey, and if she can’t take off from flat ground to avoid trouble once in awhile… it would only take once. Khan Chalsan had explained the necessity of having the birds in captivity for certain periods, and nesting wild at other times. A bird bigger than Atlanta would not survive the other times.
One variety of teratorn, however, judging from pictures which have appeared in the December 1980 issue of “Bioscience” magazine, was very nearly a scaled-up golden eagle weighing 170 lb. or so, with a wingspan of 25′ as compared to Atlanta’s 10. In our world, that can’t happen.