8 ms·

Why we think giant pterosaurs could fly (2018)

129 points by curtis 8y ago

samastur 8y ago
"Predicted giant flight velocities exceeded 90 kph and, in that 90 second flapping burst, giant azhdarchids would cover several kilometres - plenty of distance to seek areas of uplift such as deflected winds or thermals." I have a small issue with this statement. 90kph for 90 seconds is only enough for a bit more than 2km of flight and probably even less since accelerating to this speed would take not be almost instantaneous either.
- jhauris 8y ago
  "Several" may have been an exaggeration, but their quadrapedal launch makes it look like they accelerated very quickly, unlike what we naturally envision when thinking of birds. (FTA) https://www.youtube.com/watch?v=ALziqtuLxBQ https://www.youtube.com/watch?v=ALziqtuLxBQ
- ncmncm 8y ago
  2.25 km is a hell of a long way for an animal to get in 90 seconds, no matter how you slice it.
autokad 8y ago
i knew they were big, but oh man I didnt know they were that big, amazing
danteembermage 8y ago
I tend to think atmospheric pressure was higher then: https://gdesilvestri.wordpress.com/2015/10/13/was-the-atmospheric-pressure-different-at-the-time-of-dinosaurs-o-levenspiel-a-small-tribute/ https://gdesilvestri.wordpress.com/2015/10/13/was-the-atmosp...
- otabdeveloper1 8y ago
  Yeah. The assumption that the Earth's environment parameters have been stable for billions of years is bunk. (Especially ironic if the person is railing about 'global warming' at the same time.)
  - acqq 8y ago
    Implicit in your sentence is however an assumption that there was any life comparable to today's during the "billions of years" which is false. More than just 500 million years ago there were not even plants on the land: https://en.wikipedia.org/wiki/Timeline_of_plant_evolution https://en.wikipedia.org/wiki/Timeline_of_plant_evolution So it's simply wrong mentioning "billions of years" when humans worry for the environment in which they can live while depending on it. For most of the "billions" of years on Earth, there wasn't anything on land, and the "life" in oceans was not something we understand as today's life, and the environment could not support our life (as in, there was not even enough oxygen!). The Earth started to "resemble its present state" only less than 400 million years ago: https://en.wikipedia.org/wiki/Timeline_of_the_evolutionary_history_of_life https://en.wikipedia.org/wiki/Timeline_of_the_evolutionary_h... Human civilizations exists only less than ten thousands of years, during which the climate was very stable (until the recent human influences): https://en.wikipedia.org/wiki/History_of_the_world https://en.wikipedia.org/wiki/History_of_the_world
    - otabdeveloper1 8y ago
      You're replying to voices in your head, it seems. I never mentioned anything about any form of life at all. (Or any time scales either, for that matter.) My comment was that the 18th century idea of uniformitarianism (https://en.wikipedia.org/wiki/Uniformitarianism https://en.wikipedia.org/wiki/Uniformitarianism) is obviously wrong, and discussions about prehistory need to take this into account.
      - acqq 8y ago
        Luckily, everybody can see what you have actually written before. The "18th century idea of uniformitarianism" was definitely not your main problem there, rather the much more recent developments.
- acqq 8y ago
  The writing of that author you link to nicely matches the description from the other article of the author posted originally (Mark Witton): http://markwitton-com.blogspot.com/2019/02/how-to-spot-palaeontological-crankery.html http://markwitton-com.blogspot.com/2019/02/how-to-spot-palae... Mark Witton: "Another major red flag common to all cranks is their frequent comparison between themselves and scientists who received establishment pushback against their ideas - Wegner, Galileo, Darwin and so on." The article you posted: "It is admirable how the persistent efforts of a handful of Wegener’s converts were able to overcome the arrogance of the majority." ... "This present article is having a somewhat similar history." Mark Witton: "Saving the best until last: yes, unbelievable as it is, there are individuals who suggest mainstream scientists are somehow organising against them to suppress their work. While maybe not imagining something as sinister as the Big Pharma conspiracy, some cranks infer that palaeontology is governed by individuals who dictate what is and what isn't acceptable science, and who forbid the publication of work that challenges the status quo." The article you posted: "This paper in its various versions has had a battered history. Here are the journals that were sent this paper and either returned it unread or just discarded it." "It seems that this paper is too radical for today’s journals." By the way, the article from your link is not by the guy who posted the copy of it on his blog, but by a much older chemist: https://issuu.com/pedrott600re/docs/levenspiel.com_octave_ol_images_web https://issuu.com/pedrott600re/docs/levenspiel.com_octave_ol...
- thaumasiotes 8y ago
  Wouldn't that just mean everything was more buoyant? How does that hurt the conclusion?
- dvdkhlng 8y ago
  Here's another article discussing various theories about past earth's atmosphere: http://pubs.acs.org/subscribe/archive/ci/30/i12/html/12learn.html http://pubs.acs.org/subscribe/archive/ci/30/i12/html/12learn...
  - acqq 8y ago
    Actually a newer “version” by the same chemist who's text was just copy pasted by that Ing. (i.e. Engineer) guy (who names that copy-pasting “A small Tribute”) That (the newer one, from your link) was published by: “Chemical innovation 30 (12), 50-55, 2000” Compare with the peer reviewed, not confirming "many times higher pressure" claim: http://science.sciencemag.org/content/342/6154/101 http://science.sciencemag.org/content/342/6154/101 "We show from the analysis of nitrogen and argon isotopes in fluid inclusions trapped in 3.0- to 3.5-billion-year-old hydrothermal quartz that the partial pressure of N2 of the Archean atmosphere was lower than 1.1 bar, possibly as low as 0.5 bar, and had a nitrogen isotopic composition comparable to the present-day one. These results imply that dinitrogen did not play a significant role in the thermal budget of the ancient Earth and that the Archean partial pressure of CO2 was probably lower than 0.7 bar." There is sure possibility that the pressure changed through the times, but not alk “proofs” are real proofs.
- Tor3 8y ago
  One point of the article is that there's no need for a higher athmospheric pressure to explain pterosaurs flight. It would work fine under the conditions we have today.
- mrfusion 8y ago
  GOOD point. Also o2 was higher leading to more compact powerful muscles?
  - LifeLiverTransp 8y ago
    If some deactivated ancient genes reactivate, due to high co2, we are going to have that again :D
andrewflnr 8y ago
This is an exceptionally kickass piece of popular science writing. Chock full of interesting facts that (AFAICT) preserve scientific objectivity and skepticism without getting too technical for a lay audience to follow. Also: > Mike has presented calculations that these giants would have sufficient on-board energy resources to travel the planet, their speed and flight range being sufficient to ignore most geographical barriers. This made me, sitting at my computer in 2019, a little bit scared of pterosaurs. The thing can come from the other side of the world and gobble you up like a snack.
- skrebbel 8y ago
  There are plenty of birds that travel between southern Africa and Europe every year. Sure, they take breaks unlike the Pterosaur would've, but still, it's not that special.
  - mcv 8y ago
    They're not as big as a flying giraffe with a gigantic beak, though.
    - prawn 8y ago
      There was a stork that migrated to Europe with an African spear lodged through it. That's something. Actually, many of them: https://en.wikipedia.org/wiki/Pfeilstorch https://en.wikipedia.org/wiki/Pfeilstorch
      - setr 8y ago
        ..and this was how we learned about migration? That’s such an absurd way to discover it
        njarboe 8y ago
        Seems very reasonable to me. Here are some other theories at the time from the wiki article about where birds came from: "Some theories of the time held that they turned into mice, or hibernated at the bottom of the sea during the winter, and such theories were even propagated by zoologists of the time."
curtis 8y ago
If you're looking for more details, check out On the Size and Flight Diversity of Giant Pterosaurs, the Use of Birds as Pterosaur Analogues and Comments on Pterosaur Flightlessness: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0013982 https://journals.plos.org/plosone/article?id=10.1371/journal...
Simple_Guy 8y ago
Reading through this, it reminds me of pointless arguing of whether superman can beat goku. There's a lot of logic and maths, from both sides, yet in the end it would be impossible to know the answer.
- fsloth 8y ago
  Um, no. There is an established scientific community around pterosaurs. The difference between pterosaurs and Superman is that between a natural historical entity and a comic book character.
- Tor3 8y ago
  Logic and maths don't work for Superman and Goku. Logic and maths do work for giant pterosaurs though. That's a big difference.
jeffdavis 8y ago
Perhaps ptersaurs could also use their long necks and big heads to start their center of gravity higher before launch? Dropping a mass (head/neck) from higher up while launching keeps the center of gravity about the same requiring much less effort for the critical "get off the ground" phase. Perhaps the article addressed this; I'm only halfway through.
- prawn 8y ago
  Pelicans, which have always reminded me of pterosaurs, seem to do this slightly when they launch. Video I took the other week of one: https://serio.com.au/images/projects/eyre-peninsula-videos/SERIO-20190301-0266.mp4 https://serio.com.au/images/projects/eyre-peninsula-videos/S...
  - Tor3 8y ago
    It's very different actually - the pelican, as every other bird, uses its hind legs to push off, while the pterosaurs (and some bats) push off with their forelegs - and the latter ones are very powerful and can be re-used for flight, unlike the powerful hindlegs of large birds which are just dead weight when they're airborne.
- cma 8y ago
  If the muscles could do it it would be better to start head low and get it moving upwards fast as possible while making ground contact for a lot of upwards momentum, then at apogee of head height drop it.
kqr2 8y ago
Be sure to watch the quad launch video on how they believe pterosaurs actually took off: https://www.youtube.com/watch?v=ALziqtuLxBQ https://www.youtube.com/watch?v=ALziqtuLxBQ
- sliken 8y ago
  Seems like a pretty poor model. Note that at the second it leaves the ground the wings aren't in a position to generate lift. Yet somehow it floats away. The wings need a down stroke to generate lift at close to zero ground speed. I don't doubt the quad launch, just that animation of it.
  - lsiebert 8y ago
    Like the article says, they jump, then flap, which is also what birds and bats do.
    - garmaine 8y ago
      Except birds jump with wings in position to flap. The quad launch would require moving wings into position which not only takes time, but also counteracts by providing drag. I trust the simulations mentioned in the article take this into account, but the grandparent is right that this is not it all obvious from the video. In fact the video shows very leven flight motion while the wings are brought up, which absolutely would not be the case.
      - ncmncm 8y ago
        You did notice that the video just shows the bones, right? Flight surfaces and muscles will cost you extra. The key bit is right at the end, showing launch in real time. There is no descent for lack of lift because there is no time for it to happen in. While the animal is still rising from the jump, the wings swing out and take up the load, in a fractional second. It would be terrifying to have it happen toward you, even as it swept over.
  - mannykannot 8y ago
ncmncm 8y ago
As a bonus, the article explains why we never got birds that big: birds depend on their feet for help launching, where the extra leg musculature competes with wings in the weight budget. The heavy muscles needed for azhdarchid launch are also flight muscle.
mcguire 8y ago
"The second source of frustration is that, away from technical literature, discussions of giant pterosaur flight frequently suffer from major cases of Dunning-Kruger effect, especially when parties have knowledge of planes. I've experienced this a lot in my career, and not just in the wilds of social media: many of my TV and film consultancy jobs have required defending basic tenets of pterosaur anatomy - even their basic, there-for-all-to-see proportions preserved in articulated fossils - to folks who just can't or won't believe what the fossils show. Having a casual understanding of engine-driven man-made flying machines does not equate to knowing all there is about everything that has ever flown, but you would not know this from some conversations." It's nice to know that humanity is the same everywhere. As for me, I'm more curious about their heads. For an animal the size of a giraffe, they're feckin' huge. What's up with that?

129 points by curtis 8y ago

"Predicted giant flight velocities exceeded 90 kph and, in that 90 second flapping burst, giant azhdarchids would cover several kilometres - plenty of distance to seek areas of uplift such as deflected winds or thermals." I have a small issue with this statement. 90kph for 90 seconds is only enough for a bit more than 2km of flight and probably even less since accelerating to this speed would take not be almost instantaneous either.

jhauris 8y ago
"Several" may have been an exaggeration, but their quadrapedal launch makes it look like they accelerated very quickly, unlike what we naturally envision when thinking of birds. (FTA) https://www.youtube.com/watch?v=ALziqtuLxBQ https://www.youtube.com/watch?v=ALziqtuLxBQ
ncmncm 8y ago
2.25 km is a hell of a long way for an animal to get in 90 seconds, no matter how you slice it.

autokad 8y ago

i knew they were big, but oh man I didnt know they were that big, amazing

danteembermage 8y ago

I tend to think atmospheric pressure was higher then: https://gdesilvestri.wordpress.com/2015/10/13/was-the-atmospheric-pressure-different-at-the-time-of-dinosaurs-o-levenspiel-a-small-tribute/ https://gdesilvestri.wordpress.com/2015/10/13/was-the-atmosp...

otabdeveloper1 8y ago
Yeah. The assumption that the Earth's environment parameters have been stable for billions of years is bunk. (Especially ironic if the person is railing about 'global warming' at the same time.)
- acqq 8y ago
  Implicit in your sentence is however an assumption that there was any life comparable to today's during the "billions of years" which is false. More than just 500 million years ago there were not even plants on the land: https://en.wikipedia.org/wiki/Timeline_of_plant_evolution https://en.wikipedia.org/wiki/Timeline_of_plant_evolution So it's simply wrong mentioning "billions of years" when humans worry for the environment in which they can live while depending on it. For most of the "billions" of years on Earth, there wasn't anything on land, and the "life" in oceans was not something we understand as today's life, and the environment could not support our life (as in, there was not even enough oxygen!). The Earth started to "resemble its present state" only less than 400 million years ago: https://en.wikipedia.org/wiki/Timeline_of_the_evolutionary_history_of_life https://en.wikipedia.org/wiki/Timeline_of_the_evolutionary_h... Human civilizations exists only less than ten thousands of years, during which the climate was very stable (until the recent human influences): https://en.wikipedia.org/wiki/History_of_the_world https://en.wikipedia.org/wiki/History_of_the_world
  - otabdeveloper1 8y ago
    You're replying to voices in your head, it seems. I never mentioned anything about any form of life at all. (Or any time scales either, for that matter.) My comment was that the 18th century idea of uniformitarianism (https://en.wikipedia.org/wiki/Uniformitarianism https://en.wikipedia.org/wiki/Uniformitarianism) is obviously wrong, and discussions about prehistory need to take this into account.
    - acqq 8y ago
      Luckily, everybody can see what you have actually written before. The "18th century idea of uniformitarianism" was definitely not your main problem there, rather the much more recent developments.
acqq 8y ago
The writing of that author you link to nicely matches the description from the other article of the author posted originally (Mark Witton): http://markwitton-com.blogspot.com/2019/02/how-to-spot-palaeontological-crankery.html http://markwitton-com.blogspot.com/2019/02/how-to-spot-palae... Mark Witton: "Another major red flag common to all cranks is their frequent comparison between themselves and scientists who received establishment pushback against their ideas - Wegner, Galileo, Darwin and so on." The article you posted: "It is admirable how the persistent efforts of a handful of Wegener’s converts were able to overcome the arrogance of the majority." ... "This present article is having a somewhat similar history." Mark Witton: "Saving the best until last: yes, unbelievable as it is, there are individuals who suggest mainstream scientists are somehow organising against them to suppress their work. While maybe not imagining something as sinister as the Big Pharma conspiracy, some cranks infer that palaeontology is governed by individuals who dictate what is and what isn't acceptable science, and who forbid the publication of work that challenges the status quo." The article you posted: "This paper in its various versions has had a battered history. Here are the journals that were sent this paper and either returned it unread or just discarded it." "It seems that this paper is too radical for today’s journals." By the way, the article from your link is not by the guy who posted the copy of it on his blog, but by a much older chemist: https://issuu.com/pedrott600re/docs/levenspiel.com_octave_ol_images_web https://issuu.com/pedrott600re/docs/levenspiel.com_octave_ol...
thaumasiotes 8y ago
Wouldn't that just mean everything was more buoyant? How does that hurt the conclusion?
dvdkhlng 8y ago
Here's another article discussing various theories about past earth's atmosphere: http://pubs.acs.org/subscribe/archive/ci/30/i12/html/12learn.html http://pubs.acs.org/subscribe/archive/ci/30/i12/html/12learn...
- acqq 8y ago
  Actually a newer “version” by the same chemist who's text was just copy pasted by that Ing. (i.e. Engineer) guy (who names that copy-pasting “A small Tribute”) That (the newer one, from your link) was published by: “Chemical innovation 30 (12), 50-55, 2000” Compare with the peer reviewed, not confirming "many times higher pressure" claim: http://science.sciencemag.org/content/342/6154/101 http://science.sciencemag.org/content/342/6154/101 "We show from the analysis of nitrogen and argon isotopes in fluid inclusions trapped in 3.0- to 3.5-billion-year-old hydrothermal quartz that the partial pressure of N2 of the Archean atmosphere was lower than 1.1 bar, possibly as low as 0.5 bar, and had a nitrogen isotopic composition comparable to the present-day one. These results imply that dinitrogen did not play a significant role in the thermal budget of the ancient Earth and that the Archean partial pressure of CO2 was probably lower than 0.7 bar." There is sure possibility that the pressure changed through the times, but not alk “proofs” are real proofs.
Tor3 8y ago
One point of the article is that there's no need for a higher athmospheric pressure to explain pterosaurs flight. It would work fine under the conditions we have today.
mrfusion 8y ago
GOOD point. Also o2 was higher leading to more compact powerful muscles?
- LifeLiverTransp 8y ago
  If some deactivated ancient genes reactivate, due to high co2, we are going to have that again :D

andrewflnr 8y ago

This is an exceptionally kickass piece of popular science writing. Chock full of interesting facts that (AFAICT) preserve scientific objectivity and skepticism without getting too technical for a lay audience to follow. Also: > Mike has presented calculations that these giants would have sufficient on-board energy resources to travel the planet, their speed and flight range being sufficient to ignore most geographical barriers. This made me, sitting at my computer in 2019, a little bit scared of pterosaurs. The thing can come from the other side of the world and gobble you up like a snack.

skrebbel 8y ago
There are plenty of birds that travel between southern Africa and Europe every year. Sure, they take breaks unlike the Pterosaur would've, but still, it's not that special.
- mcv 8y ago
  They're not as big as a flying giraffe with a gigantic beak, though.
  - prawn 8y ago
    There was a stork that migrated to Europe with an African spear lodged through it. That's something. Actually, many of them: https://en.wikipedia.org/wiki/Pfeilstorch https://en.wikipedia.org/wiki/Pfeilstorch
    - setr 8y ago
      ..and this was how we learned about migration? That’s such an absurd way to discover it
      - njarboe 8y ago
        Seems very reasonable to me. Here are some other theories at the time from the wiki article about where birds came from: "Some theories of the time held that they turned into mice, or hibernated at the bottom of the sea during the winter, and such theories were even propagated by zoologists of the time."

curtis 8y ago

If you're looking for more details, check out On the Size and Flight Diversity of Giant Pterosaurs, the Use of Birds as Pterosaur Analogues and Comments on Pterosaur Flightlessness: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0013982 https://journals.plos.org/plosone/article?id=10.1371/journal...

Simple_Guy 8y ago

Reading through this, it reminds me of pointless arguing of whether superman can beat goku. There's a lot of logic and maths, from both sides, yet in the end it would be impossible to know the answer.

fsloth 8y ago
Um, no. There is an established scientific community around pterosaurs. The difference between pterosaurs and Superman is that between a natural historical entity and a comic book character.
Tor3 8y ago
Logic and maths don't work for Superman and Goku. Logic and maths do work for giant pterosaurs though. That's a big difference.

jeffdavis 8y ago

Perhaps ptersaurs could also use their long necks and big heads to start their center of gravity higher before launch? Dropping a mass (head/neck) from higher up while launching keeps the center of gravity about the same requiring much less effort for the critical "get off the ground" phase. Perhaps the article addressed this; I'm only halfway through.

prawn 8y ago
Pelicans, which have always reminded me of pterosaurs, seem to do this slightly when they launch. Video I took the other week of one: https://serio.com.au/images/projects/eyre-peninsula-videos/SERIO-20190301-0266.mp4 https://serio.com.au/images/projects/eyre-peninsula-videos/S...
- Tor3 8y ago
  It's very different actually - the pelican, as every other bird, uses its hind legs to push off, while the pterosaurs (and some bats) push off with their forelegs - and the latter ones are very powerful and can be re-used for flight, unlike the powerful hindlegs of large birds which are just dead weight when they're airborne.
cma 8y ago
If the muscles could do it it would be better to start head low and get it moving upwards fast as possible while making ground contact for a lot of upwards momentum, then at apogee of head height drop it.

kqr2 8y ago

Be sure to watch the quad launch video on how they believe pterosaurs actually took off: https://www.youtube.com/watch?v=ALziqtuLxBQ https://www.youtube.com/watch?v=ALziqtuLxBQ

sliken 8y ago
Seems like a pretty poor model. Note that at the second it leaves the ground the wings aren't in a position to generate lift. Yet somehow it floats away. The wings need a down stroke to generate lift at close to zero ground speed. I don't doubt the quad launch, just that animation of it.
- lsiebert 8y ago
  Like the article says, they jump, then flap, which is also what birds and bats do.
  - garmaine 8y ago
    Except birds jump with wings in position to flap. The quad launch would require moving wings into position which not only takes time, but also counteracts by providing drag. I trust the simulations mentioned in the article take this into account, but the grandparent is right that this is not it all obvious from the video. In fact the video shows very leven flight motion while the wings are brought up, which absolutely would not be the case.
    - ncmncm 8y ago
      You did notice that the video just shows the bones, right? Flight surfaces and muscles will cost you extra. The key bit is right at the end, showing launch in real time. There is no descent for lack of lift because there is no time for it to happen in. While the animal is still rising from the jump, the wings swing out and take up the load, in a fractional second. It would be terrifying to have it happen toward you, even as it swept over.
- mannykannot 8y ago

ncmncm 8y ago

As a bonus, the article explains why we never got birds that big: birds depend on their feet for help launching, where the extra leg musculature competes with wings in the weight budget. The heavy muscles needed for azhdarchid launch are also flight muscle.

mcguire 8y ago

"The second source of frustration is that, away from technical literature, discussions of giant pterosaur flight frequently suffer from major cases of Dunning-Kruger effect, especially when parties have knowledge of planes. I've experienced this a lot in my career, and not just in the wilds of social media: many of my TV and film consultancy jobs have required defending basic tenets of pterosaur anatomy - even their basic, there-for-all-to-see proportions preserved in articulated fossils - to folks who just can't or won't believe what the fossils show. Having a casual understanding of engine-driven man-made flying machines does not equate to knowing all there is about everything that has ever flown, but you would not know this from some conversations." It's nice to know that humanity is the same everywhere. As for me, I'm more curious about their heads. For an animal the size of a giraffe, they're feckin' huge. What's up with that?