Let's just ruin all the movies about pterosaurs: they could soar like airplanes, but they couldn't hover like hummingbirds. They couldn't carry things in their feet either, they couldn't perch on tree branches like birds, they didn't look like "bird-monsters", and they didn't look like "lizard-bats". They didn't have four-fingered wings like bats; their wings were based on an elongated pinky finger. The only thing bat-like about them was the way they walked; on all fours. So what are the possibilities for fluffy pterosaurs? We know they were a very diverse and almost certainly colorful group. They looked like a wide range of things, from fluttering bats to darting falcons. Some had powerful shell-crushing jaws and some had ridiculous crests, and some were quite huge. For decades, we were told that Pteranodon was the biggest animal that ever flew, then they discovered Ornithocheirus, then Quetzalcoatlus, then Hatzegopteryx (an apex predator)... These were capable killers of even human-sized prey, with a skull larger than that of even the biggest carnosaurs.

When it was assumed that birds did not evolve from dinosaurs, it was correspondingly presumed that their flight evolved among climbers that first glided and then developed powered flight. This has the advantage that we know that arboreal animals can evolve powered flight with the aid of gravity, as per bats. When it was realized that birds descended from deinonychosaurs, many researchers switched to the hypothesis that running dinosaurs learned to fly from the ground up. This has the disadvantage that it is not certain whether it is practical for tetrapod flight to evolve among ground runners working against gravity.
The characteristics of birds indicate that they evolved from dinosaurs that had first evolved as bipedal runners, and then evolved into long armed climbers. If the ancestors of birds had been entirely arboreal, then they should be semiquadrupedal forms whose sprawling legs were integrated into the main airfoil, like bats. That birds are bipeds whose erect legs are separate from the wings indicates that their ancestors evolved to run.

The dinosaur world I grew up in was classical. They were universally seen as scaley herps that inhabited the immobile continents. There was no hint that birds were their direct descendents. Being reptiles, dinosaurs were cold-blooded and rather sluggish except perhaps for the smaller more bird-like examples. They all dragged their tails. Forelimbs were often sprawling. Leg muscles were slender in the reptilian manner. Intellectual capacity was minimal, as were social activity and parenting; the Knight painting of a Triceratops pair watching over a baby threatened by the Tyrant King was a notable exception. Hadrosaurs and especially sauropods were dinosaurian hippos, the latter perhaps too titanic to even emerge on land, and if they did so were limited by their bulk to lifting one foot of the ground at a time. Suitable only for the lush, warm and sunny tropical climate that enveloped the world from pole to pole before the Cenozoic, a cooling climate and new mountain chains did the obsolete archosaurs in, leaving only the crocodilians. Dinosaurs and the bat-winged pterosaurs were merely an evolutionary interlude, a period of geo-biological stasis before things got really interesting with the rise of the energetic and quick witted birds and especially mammals, leading with inexorable progress to the apex of natural selection: Man. It was pretty much all wrong. Deep down I sensed something was not quite right. Illustrating dinosaurs I found them to be much more reminiscent of birds and mammals than of the reptiles they were supposed to be. I was primed for a new view.

If you saw a baby tyrannosaur you would probably think it was a weird looking bird. A full grown one might have had feathers too, maybe not on its whole body though, maybe more of an ornamental display sort of feathers. So traits in the theropod dinosaurs were more birdlike than say, crocodiles.

Twentieth-century paleontologists have fallen into the bad habit of reconstructing the dinosaurs' life functions by using crocodiles as a living model. But the earliest researchers of the nineteenth century proved beyond a doubt that the dinosaurs' powerful hind limbs must have operated like the limbs of gigantic birds.

One knew, of course, that it was not the red cape any more than it was the boots, the tights, the trunks, or the trademark “S” that gave Superman the ability to fly. That ability derived from the effects of the rays of our yellow sun on Superman’s alien anatomy, which had evolved under the red sun of Krypton. And yet you had only to tie a towel around your shoulders to feel the strange vibratory pulse of flight stirring in the red sun of your heart.

We seek not what God could have done but what He has done.… God could have caused birds to fly with bones of solid gold, with veins full of quicksilver, with flesh heavier than lead and very small and heavy wings, so as to better show His power … but He wanted to make their bones, flesh and feathers very light … to teach us that He likes simplicity and ease.

They say Archaeopteryx is proof for evolution. You got one here on the table, Brother, Archaeopteryx? Whenever you buy a bag of dinosaurs, they almost always stick one of these in there. Archaeopteryx. Wow. And this somehow gets the impression to the kids, "Wow, we've got proof that dinosaurs turned to birds. Here's one here with feathers on it." They're lying. It's still in the textbooks, I mean today, about Archaeopteryx. And it's been proven years ago, Archaeopteryx was just a bird, a perching bird. Alan Feduccia, who believes in evolution, says it's not a missing link. It had the right features for flight. All the features of the brain were for flight, okay? Archaeopteryx means "ancient wing," and he had claws on his wings. Well, that's kind of unusual, okay. But twelve birds today have claws on their wings. There is the swan, the ibis, the hoatzin... several birds have claws. They say, "Well, he had teeth in his beak." Well, not many birds have teeth, some do. There's the hummingbird that has teeth in his beak. But most birds don't have teeth, I agree. Actually, some mammals have teeth, some don't. Some birds have teeth, some don't. Some fish have teeth, some don't. Some of you have teeth, some don't, okay? Missing link!

If you take as your pattern the wings of feathered birds, these are more powerful in structure of bone and sinew because they are penetrable, that is to say the feathers are separated from one another and the air passes through them. But the bat is aided by its membrane, which binds the whole together and is not penetrated by the air.

Without doubt the most dangerous devices for active defense among the Dinosauria emerged in Triceratops. The scene has been portrayed in paintings, drawings, and illustrations hundreds of times, but it remains thrilling. Tyrannosaurus, the greatest dinosaur toreador, confronts Triceratops, the greatest set of dinosaur horns. No matchup between predator and prey has ever been more dramatic. It's somehow fitting that those two massive antagonists lived out their co-evolutionary belligerence through the very last days of the very last epoch in the Age of Dinosaurs. Tyrannosaurus stood over twenty feet tall when fully erect, and a large adult was as heavy as a small elephant - five tons. No predatory dinosaur, no predatory land animal of any sort, had more powerful jaws. Withstanding a Tyrannosaurus's attack required either tanklike armor – the approach taken by Ankylosaurus – or most powerful defensive weapons - the approach taken by Triceratops.

Most people think of pterosaurs as "flying dinosaurs". When I was a boy, I remember the other kids called them "dinosaur-birds", but they were neither dinosaurs or birds. The first problem is that most people don't know any more about the fossil record than what they've seen in a few plastic pieces in a prehistoric playset. Not only do they typically think that all these things are dinosaurs, they might even think that these are all the fossil forms that are known. They have no idea how rich the fossil record is.

The brontosaurus had thirty-ton body and a two-ounce brain. The anatosaurus had two thousand teeth. Triceratops had a helmet of filled bone seven feet long. Tyrannosaurus rex had tiny arms and teeth like six-inch razors and it was elected President. It ate everything — dead meat, living meat, old bones —

Members of the auk family, such as these guillemots and puffins... propel themselves, not with their feet like ducks, but with their wings, and they have paid a considerable price to be able to do so... Auks have had to evolve shorter, stubbier wings. That gives them a rather clumsy, whirring flight in the air, but it does enable them to "fly" underwater so well that they can outpace small fish.

When people look of non-avian dinosaur they’re thinking of extrapolating a cow up to that size. Mammals are much much denser than birds are, because a lot of the skeletons of sauropods (the big, long-necked ones—Apatosaurus, Brachiosaurus and the like) and theropod dinosaurs are just air. Theropods don’t have solid bones like we do; they have hollow bones. Sauropods don’t, but they have tremendous air sacs that fill up a lot of their bodies. And thus they weigh way less than a mammal scaled up to that size.