The fire-breathing dragons that terrorize the pages of many high fantasy stories (of which Smaug the Golden is probably the most famous) don’t exist in our world — but what if nature had gone a different way?
Over at Scientific American, science writer Kyle Hill digs into dragon evolution and the natural forces that could possibly result in giant fire-breathing lizards roaming the Earth.

Citing examples such as methane gas, gut bacteria, specially developed organs, hypergolic reactions (like we can see today in the bombardier beetle), flint-lined teeth, and potential piezoelectric properties — along with a voracious appetite to fuel the fire — Hill hypothesizes that a fire-breathing reptile just might be possible in our reality.
But even if such a reptile was living today, could a beast as massive as Smaug actually take flight? That’s a different story entirely.