How flying reptiles rose

Earl Cox, Redondo Beach, CA — Wed, 07 Jan 2009 01:23:58 GMT

I have had a life-long love affair with pterosaurs and found this article extremely interesting. How the truly large species managed to take to the air has been a long standing mystery. This article makes some important strides toward resolving this puzzle. Although I do take exception to Witton's "stupidly big" characterization. Size is a response to evolutionary pressures and is 'selected for' like any other feature of the taxonomy. Pterosaurs were, after all, highly successful over a very wide geographic range. The use of "stupid" is an echo of a now discredited view that dinosaurs and their mesozoic cousins were dim-witted, lugubrious creatures ordained to die out as a result of their own excesses.

Earl Cox
(author, with Greg Paul (artist and paleontologist), of Beyond Humanity - Cyberevolution and Future Minds)

How flying reptiles rose

Travis Lewis, Oakridge, Or. — Wed, 07 Jan 2009 02:15:24 GMT

has anyone cared to look at birds, really, the bigger the bird the slower it will flap its wing.

How flying reptiles rose

Nick Sapoznick, Seattle, Washington — Wed, 07 Jan 2009 03:08:16 GMT

Is this like wondering how a penguin could fly? With a long neck it could ambush its prey while submerged, and also the shape of the body looks apt for rolling like an aligator. It just seams that with a murky world, marsh and river laden that this wasnt a flyer from the pictures I'v seen. Also have these remains been found in what would have been high or predominantly low elivations, not to say that no dinosaurs flew? No internet sarcasim I'm realy currious.

How flying reptiles rose

Jimmy Wang, NY, NYC — Wed, 07 Jan 2009 03:56:26 GMT

This is very interesting. Explains a lot.

How flying reptiles rose

Jason Engel, Streamwood, IL — Wed, 07 Jan 2009 04:48:05 GMT

Maybe I read Witton's "stupidly big" comment from a different perspective and/or background that Mr. Cox did. If used in the manner my kids currently do, it would mean dumbfounding or jawdropping, as in "dumbfoundingly big" or "jawdroppingly big" or similarly holy-cow-that's-huge variety of big. I didn't take it to mean the Mr. Witton thought these animals were idiots. Maybe I'm wrong, but that's my take on it.

How flying reptiles rose

Earl Cox, Redondo Beach, CA — Wed, 07 Jan 2009 05:59:24 GMT

Just a note to Nick. Pterosaurs were not dinosaurs. All dinosaurs were terrestrial. Also, the late Cretaceous particularly in the northern hemisphere was, as a rule, not the swampy very-hot world of the Triassic or early to middle Jurassic. This was a world of emerging flowers and grasses, hardwood forests, receding oceans, mountains, and rolling hills. We can tell from limestone impressions that pterosaurs were flying creatures often covered in a fine layer of light fur.

Jason -- you have a point. I might have read more into that comment than intended. Still....

How flying reptiles rose

Larry Williams, San Bernardino, CA — Wed, 07 Jan 2009 08:09:42 GMT

I just have to say that this is amazing. I honestly believe this is the first time I have ever seen these creatures put into perspective in such an effective way. I just can't imagine seeing a giraffe fly over my head. How high would they have to leap to become airborne? What was their wing span and surface like. I think you convinced me that dragons were real.

How flying reptiles rose

Martin g — Wed, 07 Jan 2009 13:40:11 GMT

The researchers note :

“If a creature takes off like a bird, it should only be able to get as big as the biggest bird.”

Are they perhaps overlooking an important detail ?

At the time, the CO2 levels in the atmosphere were far higher than they are today - in other words the air was considerably more dense.

This would give any flapping-wing creature a lot more 'lift '.

Has this been taken into account ?

How flying reptiles rose

isadorahrenandez,miami,florida — Wed, 07 Jan 2009 13:41:32 GMT

so what your saying that connected i know that but how and why birds? they couldn't be connected to sting rays i mean its possible........

How flying reptiles rose

Dave, Huntsville, Alabama — Wed, 07 Jan 2009 13:54:12 GMT

The author states that because fossils of large pterosaurs "are often found miles and miles and miles from the nearest cliff...& in sediments deposited on floodplains and rivers well inland" that this indicates that they could take off from level ground.

However I would like to point out that these pterosaur fossils found on what had been level ground might indicate that once they landed there they were stuck there, & that is why they became fossils.

How flying reptiles rose

zoso — Wed, 07 Jan 2009 14:25:44 GMT

many bats walk on all fours when on the ground- the vampire bat for one- how do they get airborne again ? --- or are we just questioning this cause of the size of the dinosaur?

[ALAN ADDS: Yes, in fact, Habib cited the vampire bat as an example during my conversation with him. I recently reviewed a new book about vampire bats and other bloodsuckers, called "Dark Banquet," that devoted some ink to how bats get around:]

http://cosmiclog.msnbc.msn.com/archive/2008/10/31/1622447.aspx

How flying reptiles rose

Eric, Salinas, CA — Wed, 07 Jan 2009 15:17:34 GMT

Great article Alan! What a wonderful thing it is to be able to figure out how pterosaurs took off. I think I like this new idea that they used their muscular forelimbs. So ironic that we are studying old flying reptiles to figure out new methods of flight. Amazing that such big birds could fly at all and hopefully they'll be able to figure out how these flying reptiles evolved the ability to fly.

How flying reptiles rose

barbara deering, north miami beach, fla — Wed, 07 Jan 2009 15:31:30 GMT

Hence, flying dragons.

How flying reptiles rose

Mark Witton — Wed, 07 Jan 2009 17:34:56 GMT

Earl,

Just to clarify and, as pointed out by Mr. Engel, I don't think pterosaurs were stupid. Far from it. I just get carried away when writing and meant 'stupidly' in the colloquial sense: stupifying may have been a better word.

Oh, and just to clarify, I don't really think pterosaur launch strategies were sexy. Well, not much.

How flying reptiles rose

Aaron Labertew, Des Moines, IA — Wed, 07 Jan 2009 17:54:15 GMT

Thanks for the info Earl, its refreshing to see a professional offering their opinions and expertise on the webs. And I tend to agree with the four-legged launch theory. Like it says, if they had to rely on cliffs and hills for take-offs, they wouldn't be found inland away from cliffs so often as they'd be easy prey otherwise.

How flying reptiles rose

Andy O, Birmingham UK — Wed, 07 Jan 2009 18:24:29 GMT

Anyone considered comparing these creatures with modern bats. The have long forearms and short legs and they manage to get of the ground ok?

How flying reptiles rose

Harry D, Baltimore, MD — Wed, 07 Jan 2009 20:22:56 GMT

Just a note to Earl. Not all dinosaurs were terrestrial. Non-avian dinosaurs became extinct at the end of the Cretaceous. Flying dinosaurs - birds are still alive and well.

How flying reptiles rose

hdrkid, miami, USA — Wed, 07 Jan 2009 22:48:13 GMT

I would like to go back in time and ride one!

How flying reptiles rose

Earl Cox, Redondo Beach, CA — Wed, 07 Jan 2009 23:30:27 GMT

Harry,

A point well taken. I was referring, of course, to the general misconception that marine and flying reptiles of the mesozoic where dinosaurs. I certainly believe that modern birds are the evolutionary off-spring of avetheropods and classification schemes based on cladistics have long taken this position. Recent discoveries in China of the highly feathered cousins of Ornitholestes and Velociraptor antirrhopus have made the relationship between dinosaurs and birds very clear. In fact, birds are dinosaurs.

How flying reptiles rose

Bootoyou — Thu, 08 Jan 2009 00:29:22 GMT

Even an albatross needs a considerable headwind to get airborne. Pterosaurs most likely soared and didn't do much flapping. Their muscular legs might be due to climbing cliffs so they could take off and soar. Look at a bird, most of their musculature is devoted to flight. I doubt if a pterosaurs could jump into calm air and achieve flight -- they weighed too much. Plus the planform of the pterosaurs wing more closely resembles soaring birds than flappers. Again, look at the trouble an albatross has getting into the air. They have super efficient wings and don't have that huge neck and heavy legs.

How flying reptiles rose

Peter Kolar, Baraboo, Wisconsin — Thu, 08 Jan 2009 05:41:21 GMT

Anyone ever consider that perhaps gravity was a lot lower back in the dinosaur days? Open your mind to the possibility of say 1/2 or 2/3 our present gravity, and suddenly you can visualize the development of huge flying animals, plus massive T-Rexes that aren't crushed under their own weight (like beached whales), and an extinction theory that doesn't need to involve cataclysmic volcanoes or asteroids: Maybe as gravity increased, the bigger, heavier guys just couldn't compete anymore.

How flying reptiles rose

Mike Habib, Baltimore, MD — Thu, 08 Jan 2009 06:50:47 GMT

A couple of quick comments that might help clarify:

- I have done calculations using a Cretaceous atmosphere, but it doesn't make much of a difference. The CO2 spikes didn't change the total air density all that much. In fact, a flying animal sees larger density differences while gaining altitude.

- Regarding flightless pterosaurs: the largest pterosaurs actually show, if anything, increased flapping capacity (relative to size). The flight muscle attachment sites are relatively enlarged, rather than reduced (as would be expected from a flightless form). Of course, wing-propelled swimmers (like penguins) are an exception to the rule of muscle size, but they have a wide range of aquatic adaptations, including changes in the wings that render them more flipper-like. We don't see any such adaptations in any pterosaurs.

Thanks to everyone for the excellent thoughts and interest.

How flying reptiles rose

nemo, Hamilton, Montana — Thu, 08 Jan 2009 15:46:27 GMT

Why doesn't anyone talk about the T-Rex found in Montana with flesh still on the bones?

How flying reptiles rose

Christopher — Thu, 08 Jan 2009 15:48:31 GMT

I still can believe people are buying this absurd theory. Let's see, so this creature the size of a giraffe somehow intuitively evolves into a flying machine. It somehow intuitively perceives it's need to fly, so it takes thousands if not millions of years to develop wing and walks around with those wings for thousands of years until it one day knows to "take flight". My word people, stop being so gullible for the sake of intellectual pride and conceit.

How flying reptiles rose

Tim Rommes, Washington, UT — Thu, 08 Jan 2009 16:04:17 GMT

Calling birds dinosaurs is an extremely technical application of the word. This kind of thinking would allow you to say that the Jews of Biblical times are still around because there descendants are still around. Of course, those people are actually dead. The reality seems to be that in ancient times there were no red breasted robins, orieles, cardinals, swans, etc. and that no species that were alive then are alive now. As far as species go dinosaurs are extinct. Unless we can broaden things to include sharks and alligators, they may exist as the same species they were.

How flying reptiles rose

krill, Los Angeles, CA — Thu, 08 Jan 2009 16:58:28 GMT

Earth's gravitational pull was less back then. YouTube: "Neal Adams".

How flying reptiles rose

JT Gordon — Thu, 08 Jan 2009 18:00:07 GMT

The illustration would seem to depict a fish eating beak. Why wouldn't the "wings" have developed to "fly" under water?

Large "winged" animals may have miniaturized and taken to the air to escape aquatic predators.

Ever seen a ray "fly" underwater and propel itself into the air to slap parasitic fish off its belly on the surface of the water? (Cartilage obviously can't become lightweight and hollow the way bone can.)

How flying reptiles rose

Dave, OK — Thu, 08 Jan 2009 22:04:12 GMT

Christopher, are you trying to set up a straw man argument against the theory of natural selection, or do you just completely misunderstand the theory? Keep in mind that the smallest pterosaurs (smaller than domestic cats) share a common ancestor with the largest pterosaurs (the size of giraffes). It seems, then, that the common ancestor of this very diverse group of animals already had wings and was flight-capable! The size differentiation must have occured after wings an flight evolved in the common ancestor. Furthermore, wings and flight almost certainly co-evolved, rather than one coming before the other. Perhaps the common ancestor was a small species that found it useful to jump between tree tops, and gradually acquired increasingly adaptive traits (ultimately, wings) to give it lift (ultimately, fight). [...]

How flying reptiles rose

Scott Boerman, Lapeer, Michigan — Fri, 09 Jan 2009 01:25:19 GMT

So this creature just evolves (decides?) it needs to fly, so in tiny steps over millions and millions of years, the hundreds of physiological changes come through mutations, and natural selection then saves all of these worthless (as individual) changes until all of the pieces are in place and then one of these beasts flies. And just finding some fossils and describing this fairy tail with sophisticated terms qualifies as science?

Despite the very appealing concept; I think it deserves a little skeptical evaluation which seems to be very lacking.

How flying reptiles rose

Mike A, San Diego, California — Fri, 09 Jan 2009 02:36:23 GMT

Could they have had some type of spring mechanism to strengthen the first flap down? A spring would reduce the amount of work the muscles have to do during flight. Could their front food pads have skid pads so they could scrape them on the ground without injury during a difficult take-off or landing?

How flying reptiles rose

Earl Cox, Redondo Beach, CA — Fri, 09 Jan 2009 03:27:52 GMT

Tim, calling birds dinosaurs is, I admit, a stretch, but they are connected to the dinosaurs through their evolutionary history. You miss the point in the comparison with ancient Jews and modern birds missing from, say, the Eocene. Many paleontologists and not a few Biologists would, if they could re-write phylogenetic history, classify birds under dinosauria.

Dave (OK) has presented a very clear explanation of the mechanics underlying the evolution of large pterosaurs. Scott and Chistopher make their points with a bit too much sarcasm for my tastes, but I just think they need to spend more time studying modern evolutionary theory. Keep in mind that a species does not decide to evolve a particular feature (evolution is a blind, non-optimizing process). Elephants don't just decide it would be nice to fly and thus set about a seventy thousand millennia program of turning their ears into wings.

And JT, Pelicans actually have evolved wings that allow them to fly under water. You also raise some other interesting questions.

And Mark, congrats on your Ph.D. Well done.

E a r l

How flying reptiles rose

Earl Cox, Redondo Beach, CA — Fri, 09 Jan 2009 08:32:25 GMT

Oops! JT, I meant to say Penguins. If you ever have a chance to see them underwater, they appear to be flying. It's a beautiful sight.

How flying reptiles rose

Christopher — Fri, 09 Jan 2009 15:27:56 GMT

Dave said: Christopher, are you trying to set up a straw man argument against the theory of natural selection, or do you just completely misunderstand the theory?

At least you used the term "theory".

P.S. I have this sneaking suspicion I'm acquiring gills. You see, I do a lot of swimming.... and....

How flying reptiles rose

Tim Rommes, Washington, UT — Fri, 09 Jan 2009 22:48:21 GMT

Christopher and Scott,
Evolution is not a self directed process. The idea that something would "decide" on an adaptation is ludicrous. It's just one incremental change after another that gets added to the gene pool if that individual survives long enough. For mutations that make survival harder it is, obviously, harder for them to continue in the pool when times get tough. So a lot of mutations die out. When times are easy mutations that niether add to or take from survivability continue in the pool equally well. Any mutations that add to survivability will become stronger in the pool, particularly under stress. A mutation may be common for a million years along side the non-mutated, then a drought hits, the food supply dwindles, etc. and that mutation allows the survival of some of the species while the "normal" ones die off. After that the "normal" state of the species has changed. As far as flight goes, it probably started with ground dwelling animals that escaped predation by running. Any that developed flaps by some mechanism would enjoy a little lift while running and be a little faster. Being faster is a great way to escape the thing trying to eat you. Whereas a mutation that caused big flappy cheeks that acted as a sail when running and let their feet run out from under them would be likely to die out. Further mutation toward wings would result in a runner that could glide. Gliders that could flap well would do even better at escaping, etc. Then wings and all-out flight. And I don't think you're aquiring gills. A psychotic break perhaps.

Dave, I suspect complete misunderstanding coupled with religiously based ignorance.

How flying reptiles rose

Tim Rommes, Washington, UT — Fri, 09 Jan 2009 23:08:41 GMT

Earl, I don't think I miss the point at all. You do understand that it was not a direct comparison? We would look at people changing by generations and staying the same species. Along those same lines we can look at ancient animals changing by mutation over great lengths of time. Man 1 begat Man 2, Man 2 begat Man 3, etc. being similar to Species 1 begat Species 2, Species 2 begat Species 3, etc. As we read a man's geneology we could read a species evolutionary track. When we talk of ancient Jews we mean people who lived thousands of years ago, we could address by name if we knew it, and are now dead. We don't say ancient Jews are alive today even though we talk to their descendants. When we talk about dinosaurs we're talking about species that lived millions of years ago, we could address by genus and species name if we knew it, and are now dead. There was never an assumption of complete dieoff of all life on earth with new life forming and turning into what we see. It was always assumed that today's life evolved from the survivors following whatever chataclysm killed off the dinosaurs. We would never have historically called birds dinosaurs. If some small raptors had lived and evolved into cat-like lizards I doubt we'd ever have called them dinosaurs, either. Especially with all the reclassification confusion "dinosaur" is used as a colloqial. Applying it's jargon meaning for general application is absurd in this kind of setting. Perfectly appropriate at a paleontology convention.

How flying reptiles rose

Earl Cox, Redondo Beach, CA — Fri, 09 Jan 2009 23:58:44 GMT

I would like to point out that the word "Theory" when used in science is NOT the same as a hunch, or a guess, or a speculation, or an idea, or a possible-but-nevertheless-one-out-of-many hypotheses. A theory is a cohesive and deep explanation of a particular phenomenon that agrees with observation, has been tested by experimentation, and explains the phenomenon in ways that yield testable predictions. This confusion over the meaning of theory is most pronounced in the debate on evolution (and hence, many discussions of various phenomenology within paleontology). Science is filled with and based primarily on theories -- such as the Theory of Relativity (both General and Special). Such theories do not mean we are only making a guess about something (which would be a weak form of a hypothesis), but that we have enough consistent, testable observations to assemble a coherent explanation of the processes underlying this "something". This process of building a theory works in paleontology and genetics as it does in physics, general biology,and chemistry.

But in science, a theory is only as good as its experimental evidence. New experimental or observational results can modify a theory or, in some cases, over turn a theory. This doesn't mean a theory is only a guess, but it does mean that it is supported by extensive observational and experimental data. To say something is "just a theory" is to miss the rigor and depth of coherence in a scientific theory.

Christopher, your physiology is already fixed. Spending your entire life in and under the water will not allow you to acquire gills. Changes in the morphology or physiology of a species come about over time due to small random changes in the off-spring which would allow successive generations of off-spring to survive in a changing environment or make them better adapted to an existing environment. If you had lots and lots and lots of children and tossed each one of them in ocean, you might find one that didn't drown, but managed to survive. If he/she had off-spring and tossed them into the ocean, then perhaps one or two of them would survive and so pass this adaptation onto their offspring. If this was a recessive gene and they all died, then this survival advantage would have died out without propagating this adaptation. This is a somewhat simplified explanation -- but, Christopher, it is at least an experiment you try at home!

That's it for me on this thread. I was hoping to discuss pterosaurs.

E a r l

How flying reptiles rose

Earl Cox, Redondo Beach, CA — Sat, 10 Jan 2009 02:28:16 GMT

Tim,

I was going to jump out of this thread, however, your thoughtful and interesting comments compel me to make one last set of comments.

In your comparison with Biblical Jews, it is well to remember that in evolutionary biology we are discussing the taxonomic and phylogenic properties of a species. The culture and ceremonial dress of humanity over the millennia are constantly shifting but under all this external decoration we are homo sapiens sapiens. The culture of ancient Judea may be largely gone, but the human species remains. We cannot speak about culture in the same way that we speak about taxonomic classification. And, depending on how you classify birds, dinosaurs may not be extinct -- anymore than crocodilians are not extinct even though their Triassic and Jurassic predecessors are extinct. Birds have many of the same structural properties as small, agile theropods. The fossils of many theropods show that they were covered in feathers – most likely used in earlier species for insulation and in later species for flight. Paleontologist now classify these small, bipedal fleet footed, feathered dinosaurs as avetheropods. In my opinion, the fact that birds are not classified as dinosaurs is a matter of historical pigeon-holing in the early nineteenth century, a few decades before the first dinosaur fossils were discovered and long before we had a complete enough picture of dinosaur taxonomy to even begin to compare it with birds (although a few late nineteenth century paleontologist pointed out the considerable similarity between birds and dinosaurs). That’s my opinion (and the opinion of a large but not universal number of paleontologists and biologists). To be fair, you make a good point and we really not have enough transitional fossils and enough certainty about whether small feathered dinosaurs were exothermic or endothermic (like birds) to make a definitive judgment.

If we knew more about dinosaurs in the nineteenth century, I think we certainly might have classified them as a species of dinosaur. And why not? If a small raptor had survived the K-T extinctions, and if it, like birds, retained its dinosaur features (even if it looked like a cat) I suspect modern biologists would classify it as a species of dinosaur.

Your response to Christopher and Scott was well thought out and well written. But most paleontologists (yet not all) believe that feathers evolved along with many species of dinosaurs (the imprint of feathers have been found with baby Tyrannosaurs). A bird’s wing is a three fingered arm with feathers. This same structure has been seen in theropod fossils from fine ash deposits in China. If feathers evolved with dinosaurs then flight may have evolved in a slightly different way. But I am picking at the details here. Your over-all message was correct.

That’s it for now,
E a r l
www.futureminds.squarespace.com

How flying reptiles rose

Mike Traynor, Ottawa, Canada — Sun, 11 Jan 2009 02:19:02 GMT

"Why doesn't anyone talk about the T-Rex found in Montana with flesh still on the bones?"

Probably because it wasn't "flesh still on the bones" but some organic material found inside some of the bones and it is not yet clear whether the organic material is actually from the dinosaur itself or something else like a bacterial film. It is also not 'flesh' as one might put on the grill but if it is dinosaurian but collagen structures.

How flying reptiles rose

Ray Bilodeau, Worcester, MA — Sun, 11 Jan 2009 15:41:10 GMT

Interesting speculation and theory, not to mention an unusually good discussion. I just have one question: How do waterfowl "leap" into the air using their hind legs?

How flying reptiles rose

Tim Rommes, Washington, UT — Mon, 12 Jan 2009 19:52:19 GMT

Earl,
Yes, if we only knew then all that we know now. But that's the nature of discovery and learning.

I reread the thing with Christopher. I said probably but should have made it more clear that there are several other possibilities. I also shouldn't have used the word "flap" as I'm sure someone has read it and thought flapping motion instead of structure. Proofreading is underrated. The feather thing, I'm sure feathers originally had nothing to do with flight and were common where flight was impossible. Probably just insulation or camo that nature found another use for.

Ray,
If on land then by jumping, from the water many fowl run out into the air.

How flying reptiles rose

Nathan Myers — Wed, 14 Jan 2009 09:51:36 GMT

By day she wanders her domain, nodding occasionally to sample its faunal abundance. By moonlight she takes to the air, marauding far and wide, plunging to snatch the offspring of borderland mega-predators while they sleep, and exploding once more skyward. Who can stop her? Who can stir from slumber in time to mark her ascent? Truly she is terror from the skies, a Maastrichtian ninja.

How flying reptiles rose

Rachael Townsend, 16 years old, camp,Arkansas — Fri, 20 Feb 2009 01:23:52 GMT

there are two different theories that scientists have about how birds and flight developed. one is that that they started on the ground and the other is that they climbed and glided between trees
I am trying to figure out which story is the right one

How flying reptiles rose

Tim Rommes, Washington, UT — Wed, 25 Feb 2009 17:49:53 GMT

Rachael,
So is everybody else. It's not necessarily an either or proposition. It is possible, perhaps even likely, that it was one or the other for different species and both for some. Land based flight may have started by being lifted by wind, takeoff could have evolved into jumping then flapping or running and gliding into the air as wing surfaces became better. The same holds true for flight for elevation, just with more time to stabilize before crashing into the ground. Or it could have been something else entirely. Some science indicates evolution in complete steps instead of tiny changes that amass over time. Bottom line is groups of very intelligent people have worked for many of your lifetimes and spent more money than you can realistically hope to make in your life trying to find the answer and they haven't. Yet. They have come up with many interesting theories, any of which, or maybe all of which, may be correct.