Among the worst offenders was the 2004 “documentary” Dragons: A Fantasy Made Real, which investigated what the fire-breathing behemoths would be like if they had roamed the Earth. In addition to CGI animations, the program featured “footage” of “scientists” analyzing the gas content of a dragon’s organ and studying a printout of its DNA.According to the Animal Planet web site, dragon anatomy and physiology "fantasy facts" were inspired by real animals.
- Dragons weighed over a ton and had a 35 foot wingspan.
Inspiration: giant Cretaceous pterosaurs
(The dragons actually look like pterosaurs with an extra set of limbs)
- Dragons had six limbs: two arms, two legs and two wings
Inspiration: homeotic mutations in drosophila that produce a second pair of wings
(They should have at least mentioned Henrietta the four-legged chicken).
- Dragon wings consist of a leathery membrane supported by arm bones.
- Dragons produce flammable hydrogen gas in their guts
Inspiration: gut bacteria in plant-eating animals such as cows and hippos produce methane and small amounts hydrogen
- Dragons ingested platinum which ignites the gut hydrogen, allowing them to breathe fire
Inspiration: birds and dinosaurs ingest(ed) stones to help grind their food, and some modern elephants chip the inside walls of caves in order to ingest the salty deposits
(I suppose they also posit that there were readily accessible platinum deposits back in the dragon era too)
- Dragon wings changed color during mating displays and fights
Inspiration: moths have bold patterns on their wings to confuse or frighten potential predators
(I'm not sure how that's an inspiration for changing colors. Could they have forgotten about the color changing chromatophores of chameleons and squids?)
- Dragons engaged in dramatic courtship displays and mating rituals, involving locking talons in flight, plunging about and breathing fire
Inspiration: the acrobatic courtship of bald eagles.
It's the setting fire to the dragon that's the problem. I think our ideas were hydrogen and air mixing and exploding, and the only way we could think of it to work was the powdered platinum. We wondered if they could strike a spark against their teeth. Large dinosaurs did ingest stones to help digest their food, but the stones couldn't be large enough. There was the possibility of electricity. There are animals that create amounts of electricity — electric eels and electric rays — but they couldn't generate a spark, so the platinum theory seemed to be the best.It's a fun thought experiment, but pretty unlikely. In fact, from the descriptions it seems that the biological characteristics of dragons were selected more for their on-screen excitement than their actual biological plausibility. Definitely edutainment.
Not all fictional dragons are so biologically implausible. See, for example, James Maxey's explanation of how he designed realistic dragons for his novel Bitterwood.
For a free short story that features dragon paleontology, check out Robert Reed's "The Dragons of Summer Gulch".