Breeze: important for takeoff. Acrobatic leaping : not so much.

Pterosaur take-off analog
In this video of a glider with legs you can see it just takes a long set of wings and a stiff breeze to become airborne – not an elaborate acrobatic forelimb leap sequence. This is a good model, a good niche and a good location, for ornithocheirid and pteranodontid pterosaurs to rest, nest and take off. The invisible, but very present breeze is key to this aerie. It provides the lift. Gravity, when the nose of the aircraft is pointed down, provides the thrust.

 Click to play 48-second video of glider launching by airspeed alone caused by a stiff breeze.

Figure 1. Click to play 48-second video of glider launching by airspeed alone caused by a stiff breeze. This should put to rest all thoughts for the necessity of a dangerous and odd forelimb leap for pterosaurs, especially the big winged ones, the ornithocheirids and pteranodontids. As in airplanes, forward speed is increased by tipping the nose down.

But wait! There’s more!
Pterosaurs, of course, provided their own thrust when they flapped. So, really, why go through goofy acrobatics when all you have to do is stretch out and flap those big wings!

I mean, really!!
It’s this simple and much less risky than the alternative.

4 thoughts on “Breeze: important for takeoff. Acrobatic leaping : not so much.

  1. David, this is “science” by assertion. You are effectively saying, “Nobody before me has ever noticed that kites work, therefore pterosaurs launched this way.”

    You have not made the slightest effort to determine what sort of “breeze” would be necessary for a pterosaur to launch, or that such breezes were common in pterosaur habitats, or that any extant animals launch in this fashion and that it is therefore a viable lifestyle.

    A human with a glider or kite has the luxury of being able to wait for wind of the proper direction and strength in order to take off. An animal seeking prey, or to escape predation, would not have that luxury.

    To say this is unconvincing is an understatement.

  2. I was specific in saying for this environment and these wind conditions all you have to do is stretch out your wings. I saw no predators up there. Resting sites would probably be predator free with pterosaurs having their choice of otherwise inaccessible sites and after examining each site first from the air. I am just saying, why go through all the gymnastics when ocean breezes (where the prey lives) are reliable? The same goes for skimming and dipping. Ocean breezes create airspeed that can translate to zero groundspeed.

  3. You are not just saying that, you are saying that quadrupedal launch doesn’t happen, which is a much stronger assertion, requiring actual evidence. Even if you grant that ocean breezes are reliable, they’re only “where the prey lives” for some pterosaurs. How does this apply to azhdarchids? What wind speed is necessary to loft Quetzalcoatlus with zero ground speed?

    “I see no predators in this video” is a long way from being able to say “pterosaurs would never need to launch from a site threatened by predators.”

    What observations would your hypothesis predict that would distinguish it from quadrupedal launch? What evidence is there for those predictions?

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