
Why we think giant pterosaurs could fly (2018) - curtis
http://markwitton-com.blogspot.com/2018/05/why-we-think-giant-pterosaurs-could-fly.html
======
andrewflnr
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
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
They're not as big as a flying giraffe with a gigantic beak, though.

~~~
prawn
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
..and this was how we learned about migration? That’s such an absurd way to
discover it

~~~
Someone
This was accidental, but I think tagging individual birds to make them
identifiable by humans is still the primary way we learn about migration. The
alternative of continuously tracking individual birds wasn’t possible until
late 20th century and I think still is fairly expensive.

~~~
setr
Sure, it's just a comical predecessor to tagging

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danteembermage
I tend to think atmospheric pressure was higher then:

[https://gdesilvestri.wordpress.com/2015/10/13/was-the-
atmosp...](https://gdesilvestri.wordpress.com/2015/10/13/was-the-atmospheric-
pressure-different-at-the-time-of-dinosaurs-o-levenspiel-a-small-tribute/)

~~~
dvdkhlng
Here's another article discussing various theories about past earth's
atmosphere:

[http://pubs.acs.org/subscribe/archive/ci/30/i12/html/12learn...](http://pubs.acs.org/subscribe/archive/ci/30/i12/html/12learn.html)

~~~
acqq
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.

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ncmncm
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.

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kqr2
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
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
Like the article says, they jump, then flap, which is also what birds and bats
do.

~~~
garmaine
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
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.

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curtis
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...](https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0013982)

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

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samastur
"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
"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)

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jeffdavis
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
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/S...](https://serio.com.au/images/projects/eyre-peninsula-
videos/SERIO-20190301-0266.mp4)

~~~
Tor3
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.

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mcguire
" _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?

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Simple_Guy
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.

~~~
Tor3
Logic and maths don't work for Superman and Goku. Logic and maths do work for
giant pterosaurs though. That's a big difference.

