A reader at Upcoming Pixar who goes by the name Bryko614 spotted the framed picture hanging behind Pixar sculptor Greg Dykstra in a featurette for Up. It appears there is something to the images, because when Bryko614 tweeted Pixar artist Ronnie del Carmen, asking if he knew anything about the concept art, del Carmen replied:

@Bryko614 I do. But not telling. Nothing to do with anything Toy Story, tell you that.

Because the dinosaur doesn't seem to fit with Pixar's current slate of films (Cars 2, The Bear and the Bow, and Newt), many are speculating that the dinosaur might make an appearance in an upcoming short.

Sneak Peek at a New Pixar Production Featuring a Boy and His Dinosaur? [Upcoming Pixar via /Film]

Professor Katsufumi Sato of the University of Tokyo studied five species of soaring birds, measuring the thrust the birds require to stay aloft. He concluded that no animal that weighs more than 40kg (88lbs) could soar. The wandering albatross, which has the largest wingspan of any living bird, weighs only 22kg. Heavier birds can achieve enough thrust to take off, but cannot flap their wings quickly enough to keep their mass in the air. Pterodactyls had as much as a 15 meter wingspan, but were four times heavier than the albatross.

So were pterodactyls the turkeys of the Cretaceous Period? Not according Mike Habib, a biomechanics researcher at the Johns Hopkins School of Medicine:

One possible theory is they would rely on thermals to stay aloft having dropped off the edge of a cliff. However, evidence that they could walked for considerable distances has also been discovered.

Another theory is that their wings were so large that, relatively speaking, wing load was low. If a pterosaur spread its wings, staying on the ground would have been more of a problem than taking off.

So, until paleocloning resolves the question, we can hold onto our vision of pterodactyls in the skies.

Pterodactyls were too heavy to fly, scientist claims [Telegraph]