Dragon Physiology Old and New and Peter Dickinson and You

I was at my parent's place a week ago and my mother and I watched two of my favorite movies. When I was a kid and still now if you can take 80's animation for being 80's animation. The Last Unicorn and The Flight of Dragons.

Now it's less commonly known that The Flight of Dragons is based on a loose speculative evolution book by Peter Dickinson. So for those of you who are younger because I just dated myself there pretty well, in Flight of Dragons the aforementioned dragons have some science put into their design. Firstly they eat limestone rocks and diamonds. The diamonds act like stones in a gizzard and the limestone mixes with the gut acid there to create helium. They have two advanced air sacs that have a honeycomb like structure and they can expand and contract these at will to fill them up with helium, allowing flight despite their weight, or contract them to push the helium out. When they want to descend they must expel the helium through their mouths and in doing so it touches an organ on the roof of their mouth that contains a collection of nerves that produce bio electricity called Thor's Thimble. This electricity sparks the helium and sets it alight, allowing them to breathe fire. Only so much helium can be produced in one day so young dragons can be reckless and use it all up, leaving them unable to fly or breathe fire for the rest of the day.

That's the part of the movie that always intrigued me even as a kid. In most other movies dragons breathed fire and flew around because they were dragons and that's what dragons do. Later we see that flying is never really explained beyond wingspan ratios but fire these days tends to be a liquid or a combination of liquid produced by glands in the mouth. It's either when the chemical meets air or is combined that it ignites.

I've written all kinds of dragons and their anatomy from "simply magic" to one crocodile that ate a glowing rock and evolved. So I've always been curious at Peter's overlooked take on dragon anatomy and I would love to hear you all weigh in with how you do your designs.