DINOSAUR: Did Pterosaurs hang upside down?

I am not a paleontologist or even a biologist. I do have a science degree, but it is in an entirely unrelated subject. However there is something about how pterosaurs have been portrayed in the media that has bugged me for years. Ever since their cinematic characterisation in Jurassic Park 3 and subsequent 'natural history' depiction in the landmark BBC series 'Walking with Dinosaurs', there has been a  widespread belief by the scientific community that when Pterosaurs are not expending valuable energy flying around, they spent their lives using a horribly ungainly quadrupedal system of walking in order to get around.

On the whole, this is fine - but I have a question.  While I will accept that walking around like a decrepit old man on crutches will give you effective mobility, surely this slow, cumbersome method will make you incredibly vulnerable to attack by predators? And while I'll accept that they can fly off when danger arises, don't forget that the pterosaur family accounted for the largest creatures ever to fly.

Consider the mute swan and the great bustard. These are two of the heaviest flying birds in the world today - approximately 25 kg for an adult male, and both of these birds require substantial run-ups to launch themselves into flight.

The largest pterosaur so far discovered is the Quetzalcoatlus. With a 30 ft wingspan and weighing in at 200lbs, the scientific community is split in its opinion of whether it flew or instead  led an entirely terrestrial existence. In answer to this question, David Attenborough's recent 3D documentary on this subject takes the view that it flew, and puts forth a theory of dynamic thrust motion by the pterosaur in order to provide lift at the initial flight phase in order to provide a springboard for flight.

Be that as it may, there were plenty of pterosaur species that fit between the heaviest weight of today's flying birds and the gigantic Quetzalcoatlus. However, the likelihood of these animals being able to run fast enough using their 'quadrupedal system of walking' to achieve the critical speed for achieving powered flight is extremely low. However, if you look at the nearest contemporary flying creature that uses a quadrupedal system of walking - the bat - there is another answer to how large pterosaurs managed to obtain the initial thrust required to achieve powered flight. They amble over to the nearest tree and climb up as far as they deem necessary before jumping off! That way, gravity provides the initial acceleration necessary to instigate flight.

Of course, climbing trees with large flappy wings and tiny finger claws is extremely hard work. It is also time consuming and leaves you at a considerable risk of being predated. However, bats have an answer to this problem and that is to avoid landing on the ground and stay back in the tree when you are not flying.

Now back to my original question - did pterosaurs hang upside down in trees? Well of course,  in such a large and varied family the chances are that some of pterosaur species spent part of their lives in trees is already accepted by the scientific community. But look at the 'top heavy' pterosaur physiology and compare the skeletons of a typical bat - see left - to a typical pterosaur - see above left. A pterosaur has a large head combined with a long neck on a comparatively stubby body, supported on a branch with typically small feet. Would a pterosaur be able to comfortably stand upright on a branch with this shape of body? I believe that it would not and I would go as far to say that like a bat - the pterosaurs most similar living creature - it would hang upside down. They even have the grabby 'tree climbing' fingers that would help them climb back up if they fell out.

To conclude, I just need to say that this was all off the top of my head with no real research involved whatsoever. So I fully expect that my views on this subject will be shot down by someone who knows what they are talking about. If not, let it be known that this was my idea first, it was original, and the date of this published article will confirm that I came to this conclusion before anyone else unless proved otherwise. Any comments you wish to make can be made below.

For related articles click onto he following links:
DINOSAUR: Archaeopteryx
DINOSAUR: Did Pterosaurs hang upside down?
DINOSAUR: The Pterodactyl
LIVING DINOSAURS - The Coelacanth
TERRA NOVA - Dinosaur trailer