Bird breathing anatomy breaks dino-to-bird dogma


Photo by Steve Murray bird feet
Bird feet (red-footed booby)

Do we eat Kentucky Fried Dinosaur? According to the dogma of many evolutionary propagandists for the last decade or so, indeed we do—they believe that birds evolved from the carnivorous dinosaur group known as theropods. Yet there are many problems with this idea. And now, new research into the birds’ lung and leg anatomy provides more strong evidence against it.

Dinosaurs living today—in trees?

The BBC program Walking with Dinosaurs proclaimed that we can see and hear dinosaurs outside our windows. Many museums have proclaimed the dinosaur origin of birds as fact, such as the Australian Museum in Sydney and Queensland Museum in Australia. National Geographic was so gung-ho for this idea that they promoted Archaeoraptor, which turned out to be a “Piltdown Bird” forcing an embarrassing retraction.

Evolutionary dissent

However, there have been some lonely dissenters even among evolutionists. For example, Dr Storrs Olson, Curator of Birds at the National Museum of Natural History of the Smithsonian Institution in Washington, D.C. wrote a scathing open letter about National Geographic’s Archaeoraptor:

“The idea of feathered dinosaurs and the theropod origin of birds is being actively promulgated by a cadre of zealous scientists acting in concert with certain editors at Nature and National Geographic who themselves have become outspoken and highly biased proselytizers of the faith.”

Another skeptic is Dr Alan Feduccia, a world authority on birds at the University of North Carolina at Chapel Hill, who criticized the dogma on anatomical grounds:

“It’s biophysically impossible to evolve flight from such large bipeds with foreshortened forelimbs and heavy, balancing tails,’ exactly the wrong anatomy for flight.”1

And he criticized it on chronological grounds too. The alleged “ancestors” for birds are “dated” (by evolutionary methods) as millions of years younger than the birds. E.g., claimed “feathered dinosaur ancestors” Sinosauropteryx and Caudipteryx are “dated” at 125 Ma (million years old), which is 28 Ma younger than the first undoubted bird Archaeopteryx (153 Ma) and even about 10 Ma younger than the beaked bird Confuciusornis (135 Ma)! As Feduccia quips, you can’t be older than your grandfather! Dino-bird believers respond that sometimes a grandfather can outlive his grandson. But while correct, it’s hard to understand that an “advanced” beaked bird like Confuciusornis could appear 10 million years before there is a trace of its “feathered dino ancestors”. Also, one of the major ‘evidences’ of evolution is how the evolutionary order supposedly matches the fossil sequence. Therefore the gross mismatch with the dino-birds is a severe challenge to the evolutionary explanation.

Avian lung design

Yet another problem for the dino-bird theory is that birds and reptiles have very different lung systems. Reptilian lungs operate like bellows (like our own lungs, although the reptile lung structure is different). The stale air is then breathed out the same way it came in. But birds have a complicated system of air sacs, even involving their hollow bones. This system keeps air flowing in one direction through special tubes (parabronchi, singular parabronchus) in the lung, and blood moves through the lung’s blood vessels in the opposite direction for efficient oxygen uptake,2 an excellent engineering design.3 (See also Blown away by design, and the Avian Lung from Refuting Evolution ch. 4).

by Steve Cardno Archaeopteryx
Artist’s impression of Archaeopteryx

Recent research has shown that Archaeopteryx skeletons had pneumatized vertebrae and pelvis. This indicates the presence of both a cervical and abdominal air sac, i.e. at least two of the five sacs present in modern birds. This in turn indicates that the unique avian lung design was already present in what most evolutionists claim is the earliest bird.4

Conversely, alleged feathered dinosaur Sinosauropteryx was found so well fossilized that the outlines of some internal organs could be analysed. The lead researcher Dr John Ruben, a respiratory physiology expert at Oregon State University in Corvallis, concluded5 that its

“bellowslike lungs could not have evolved into the high-performance lungs of modern birds.”6

So the “earliest” bird had the through-flow avian lung system, while one of its closest “ancestors” had a reptilian bellows lung. The transitional forms are lacking.

Ruben noted the problem for the dino-bird theory in general: how would the ‘bellows’-style lungs of reptiles evolve gradually into avian lungs? The hypothetical intermediate stages could not conceivably function properly, meaning the poor animal would be unable to breathe. One of the first stages would be a poor creature with a diaphragmatic hernia (hole in the diaphragm), and natural selection would work against this. Ruben writes:

“The earliest stages in the derivation of the avian abdominal airsac system from a diaphragmatic-ventilating ancestor would have necessitated selection for a diaphragmatic hernia [i.e. hole] in taxa transitional between theropods and birds.

“Such a debilitating condition would have immediately compromised the entire pulmonary ventilatory apparatus and seems unlikely to have been of any selective advantage.”

New discovery: fixed thigh bone is vital for breathing

Dr Ruben has continued his research into bird breathing. Recently, he and his OSU colleague Dr Devon Quick “made a fundamental new discovery about how birds breathe and have a lung capacity that allows for flight — and the finding means it’s unlikely that birds descended from any known theropod dinosaurs.”7

It has long been known that birds have a fixed femur (thigh bone), so they are “knee runners”. Mammals and reptiles—including dinosaurs—have movable femurs that are highly involved in their walking and running. But why do birds have this unusual arrangement?

Quick and Ruben found that this fixed femur and the accompanying muscles and hip bones were essential for the bird to keep its air-sac lung from collapsing inwards when the bird inhales.8 Quick said:

“This is fundamental to bird physiology. It’s really strange that no one realized this before. The position of the thigh bone and muscles in birds is critical to their lung function, which in turn is what gives them enough lung capacity for flight.”7

But since the theropods had moving femurs, they could not have supported the air sacs needed for the avian lung system. According to a report:

“‘For one thing, birds are found earlier in the fossil record than the dinosaurs they are supposed to have descended from,’ Ruben said. ‘That’s a pretty serious problem, and there are other inconsistencies with the bird-from-dinosaur theories.

‘But one of the primary reasons many scientists kept pointing to birds as having descended from dinosaurs was similarities in their lungs,’ Ruben said. ‘However, theropod dinosaurs had a moving femur and therefore could not have had a lung that worked like that in birds. Their abdominal air sac, if they had one, would have collapsed. That undercuts a critical piece of supporting evidence for the dinosaur-bird link.

“A velociraptor did not just sprout feathers at some point and fly off into the sunset.”7

Ruben has long been sceptical of the dino-to-bird dogma, even from the 1990s. Yet he notes:

“Frankly, there’s a lot of museum politics involved in this, a lot of careers committed to a particular point of view even if new scientific evidence raises questions.”7

He pointed out that many museum displays treat the dino-to-bird theory as fact, just as we noted above. The only nod to dissent might be an asterisk with some fine print saying, “some scientists disagree.” But now Ruben says, “But now there are more asterisks all the time. That’s part of the process of science.”7

Evolutionary dogma

Photo: Don Batten Sinosauropteryx prima
Sinosauropteryx prima

Despite their rejection of dino-to-bird dogma, both Ruben and Quick, like Feduccia, believe that birds evolved from some sort of reptile. But here they become tentative, e.g. Quick says:

“We aren’t suggesting that dinosaurs and birds may not have had a common ancestor somewhere in the distant past. That’s quite possible and is routinely found in evolution. It just seems pretty clear now that birds were evolving all along on their own and did not descend directly from the theropod dinosaurs, which lived many millions of years later.”

But an evolutionary criticism of Feduccia and his supporters applies equally well to Ruben and Quick:

“Neither their hypothetical ancestor nor transitional forms linking it to known fossil birds have been found. And although they rightly argue that cladistic analyses [comparisons of shared characteristics] are only as good as the data upon which they are based, no cladistic study has yet suggested a non-theropod ancestor.”9

But goo-to-you evolution in general, not just the dino-to-bird theory, has become a dogma. Most scientists believe in evolution not because of the evidence, but because most scientists believe it. I.e. the oft-touted consensus on evolution was reached by counting heads that themselves came to this consensus by counting heads. And when asked to provide evidence, many cannot make a good case—e.g. Feduccia’s best “proof” of evolution was not in his field of ornithology, but corn turning into corn!

There is another alternative: Ruben, Quick and Feduccia are right that birds didn’t evolve from theropods; their evolutionary detractors are right that birds didn’t evolve from non-theropod reptiles. Rather, they did not evolve at all!

Published: 16 June 2009


  1. Gibbons, A., New Feathered Fossil Brings Dinosaurs and Birds Closer, Science 274:720–721, 1996. Return to text.
  2. Denton, M., Evolution, a Theory in Crisis, pp. 199–213, Adler & Adler, Bethesda, MD, 1986; K. Schmidt-Nielsen, How Birds Breathe, Scientific American, pp. 72–79, December 1971. Return to text.
  3. Engineers make much use of this principle of counter-current exchange which is common in living organisms as well—see P.F. Scholander, The Wonderful Net, Scientific American 196:96–107, April 1957. Return to text.
  4. Christiansen, P. and Bonde, N., Axial and appendicular pneumaticity in Archaeopteryx, Proceedings of the Royal Society of London, Series B.267:2501–2505, 2000. Return to text.
  5. Ruben, J.A., et al., Lung structure and ventilation in theropod dinosaurs and early birds, Science 278(5341):1267–1270, 1997. Return to text.
  6. Ruben, quoted in Ann Gibbons, Lung Fossils Suggest Dinos Breathed in Cold Blood, Science 278(5341):1229–1230, 14 November 1997. Return to text.
  7. Discovery raises new doubts about dinosaur-bird links, ScienceDaily.com, 9 June 2009. Return to text.
  8. Quick, D.E. and Ruben, J.A., Cardio-pulmonary anatomy in theropod dinosaurs: Implications from extant archosaurs, Journal of Morphology, 20 May 2009 | DOI:10.1002/jmor.10752. “The thin walled and voluminous abdominal air-sacs are supported laterally and caudally to prevent inward (paradoxical) collapse during generation of negative (inhalatory) pressure: the synsacrum, posteriorly directed, laterally open pubes and specialized femoral-thigh complex provide requisite support and largely prevent inhalatory collapse.” Return to text.
  9. Shipman, P., Birds Do It … Did Dinosaurs? New Scientist 153(2067):26–31, 1997, p. 28. Return to text.

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Refuting Evolution
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