Scicurious | Science News



Support credible science journalism.

Subscribe to Science News today.


A peek behind the science curtain

Bethany Brookshire



Want to build a dragon? Science is here for you

However, bringing the ingredients together without harming the dragon could get explosive

illustration of a dragon breathing fire

Dragon fire is the realm of fantasy. But if a dragon did exist, nature has the tools to give it fire-breathing abilities.

Sponsor Message

No fantasy world is complete without a fire-breathing dragon. SpaceX founder Elon Musk even wants to make a cyborg version a reality, or so he tweeted April 25. But if someone was going to make a dragon happen, how would it get its flame? Nature, it seems, has all the parts a dragon needs to set the world on fire, no flamethrower required. The creature just needs a few chemicals, some microbes — and maybe tips from a tiny desert fish.

Fire has three basic needs: something to ignite the blaze, fuel to keep it burning and oxygen, which interacts with the fuel as it burns. That last ingredient is the easiest to find. Oxygen makes up 21 percent of Earth’s atmosphere. The bigger challenges are sparking and fueling the flame.

All it takes to strike a spark is flint and steel, notes Frank van Breukelen, a biologist at the University of Nevada, Las Vegas. If a dragon had an organ like a bird’s gizzard, it could store swallowed rocks. In birds, those rocks help get around a lack of teeth, allowing them to break down tough foods. Inside a dragon, swallowed flint might rub against some steel, sparking a flame. “Maybe what you have is sort of scales that are flintlike and click together,” van Breukelen says. If the spark was close enough to a very sensitive fuel, that might be enough to ignite it.

illustration of pigeon anatomy
But some chemicals don’t need that initial spark. Pyrophoric molecules burst into flame the instant they contact air. Consider the element iridium, says Raychelle Burks, a chemist at St. Edwards University in Austin, Texas. It burns different colors when it becomes part of various molecules. One of them burns a warm orange or red. Another burns a violet-blue. (That’s one way to get the blue flame of the zombie ice dragon in George R.R. Martin’s Game of Thrones series.)

Unfortunately, iridium isn’t common, especially in biology. “There are a lot of cool elements on the periodic table, but [living things] only use a few,” Burks explains.

There are other pyrophoric chemicals that a dragon might find a little closer to home, notes Matthew Hartings, a chemist at American University in Washington, D.C. Assume that dragons like caves, he begins. “If you’re living amongst a bunch of rocks, you’ll have access to a high amount of iron.”

Iron can react with another chemical, hydrogen sulfide. This is a flammable gas that smells like rotten eggs, and gives Uranus its new signature scent. It is found in crude oil. When hydrogen sulfide and iron get together — in a rusty oil pipe, for example — the result is iron sulfide. Combine it with air and you’ve got an explosive mix. Iron sulfide is sometimes the culprit when gas pipelines or tanks blow up.

Another explosive option comes from Anne McCaffrey’s series The Dragonriders of Pern. McCaffrey describes her dragons chewing on rocks containing phosphine, a chemical made of one phosphorus atom and three hydrogen atoms. In gas form, phosphine is extremely flammable and explodes on contact with oxygen. It’s also very toxic: Just seven drops of its liquid form can kill someone.

Burning burps

Fictional dragons often spout flaming gas. But a gas would present problems, Hartings says. Gas, he notes, expands to fill available space. To keep it contained, a dragon would have to keep that gas under pressure.

Chemicals like phosphine, therefore, aren’t the perfect dragon-fire solution, Hartings says. The boiling point for phosphine is -84° Celsius (-120° Fahrenheit). At room (or dragon breath) temperature, it’s a gas. “You’d have to really compress it,” he says, to make it a liquid that a dragon could store and use.

Also, Hartings notes, gases are difficult to control. If a dragon blew some fiery gas into the wind, the flames might wash back on the creature and singe its face. “You have a much better chance of controlling your flame spray if you’re pushing liquid rather than a gas,” he explains.

A liquid also would help avoid self-burning, Hartings notes. The liquid with its flammable gas would ignite as soon as it hit air. Speed is key. “As long as you are shooting it out fast enough, [the] particles don’t hit the air until they are far enough away from your face,” he notes.

A combination of liquid and gas might work even better, Burks suggests. In an aerosol spray, tiny liquid droplets are suspended in a pressurized gas, which spurts out when it is released. If a dragon were to shoot an aerosol spray, it could look like a gas, with some of the properties of a liquid. “In a fine aerosol spray it would look like the dragon is spraying fire,” Burks notes. The aerosol would spread out, she says, “and the minute it hits air — kaboom!”

Something fiery, something fishy

Plenty of liquids in nature will burn. Living things already produce two of these that might work for a dragon: ethanol and methanol. Both are alcohols often burned as fuels.

“Certainly, we know that yeast makes ethanol,” Hartings says. These single-celled fungi transform sugars into alcohol. That’s why they’re used to brew beer and make other alcoholic beverages. A dragon with a bellyful of yeast is not as silly as it might appear. Yeast are part of the microbial community that lives on and in people and other animals.

Methanol first requires methane. Ruminants — including cows, goats, giraffes and deer — make methane during digestion. Certain bacteria can turn methane into methanol, Hartings notes. A dragon that got enough fiber in its diet to make methane could pass that gas on to its bacterial buddies, who would convert it into methanol. 

Devil’s Hole pupfish
But those bacterial coworkers might not even be needed. The Devil’s Hole pupfish doesn’t bother with them. The fish are a tiny, incredibly rare species found in Devil’s Hole — a single, naturally heated pool in Nevada. This fish can whip up its own whiskey in a pinch, van Breukelen and his colleagues have shown.

Temperatures in Devil’s Hole reach 33 °C (91 °F). There is very little oxygen in the water to start with. When it gets hot, the oxygen levels drop even lower — too low for the fish to breathe. So pupfish stop using oxygen. Instead, they produce energy anaerobically, no oxygen required. In the process, their bodies make ethanol.

The fish produce 7.3 times more ethanol than fish living in cooler water, van Bruekelen and his colleagues reported in 2015 in the Journal of Experimental Biology.

A dragon might be able to produce ethanol under similar circumstances. However, van Breukelen says, it’s not quite so simple. “I don’t think there’s a way to keep ethanol. I don’t think you could store it,” he says. The reason: It seeps through everything. Ethanol, he explains “goes right through membranes.” Those include the membranes that surround cells and organs. When pupfish produce ethanol, the chemical ends up throughout the fish. It would not pool as a concentrate in some pouch or organ. So any dragon that made ethanol would have trouble storing enough to get a decent flame going.

The pupfish won’t be setting the world on fire — nor will dragons. One is a tiny fish, and the other isn’t real. But if Musk wants to figure out how to make his cyborg dragon light up the world, he doesn’t need to look to fossil fuels. Nature has him covered.

This article originally appeared on Technically Fiction, a blog at Science News for Students that finds the science in the realm of the fantastic.

Science & Society

Wikipedia has become a science reference source even though scientists don’t cite it

By Bethany Brookshire 7:00am, February 5, 2018
Wikipedia is everyone’s go-to source. Even scientists. A new study shows how science on Wikipedia may end up forwarding science itself.
Neuroscience,, Human Development

Even brain images can be biased

By Bethany Brookshire 7:00am, December 15, 2017
Brain scan studies that are drawn from rich and well-educated groups could lead to biased ideas of how our brains develop.

Whether psychology research is improving depends on whom you ask

By Bethany Brookshire 8:00am, October 29, 2017
Psychologists are pessimistic about the state of their field but want to improve, a survey shows. But are new measures working?

Two artificial sweeteners together take the bitter out of bittersweet

By Bethany Brookshire 1:30pm, September 14, 2017
Some artificial sweeteners are well known for their bitter aftertastes. But saccharin and cyclamate are better together, and now scientists know why.
Science & Society

On social media, privacy is no longer a personal choice

By Bethany Brookshire 3:30pm, August 24, 2017
Data from the now-defunct social platform Friendster show that even people not on social media have predictable qualities.
Psychology,, Science & Society

Running is contagious among those with the competitive bug

By Bethany Brookshire 11:00am, May 26, 2017
Can behaviors really be contagious? Runners log more miles when their friends do — especially if they want to stay leader of the pack, a new study finds.
Archaeology,, Animals

How the house mouse tamed itself

By Bethany Brookshire 7:00am, April 19, 2017
When people began to settle down, animals followed. Some made successful auditions as our domesticated species. Others — like mice — became our vermin, a new study shows.
Science & Society

Most Americans like science — and are willing to pay for it

By Bethany Brookshire 1:00pm, March 24, 2017
Americans drastically overestimate how much the government spends on science. But when correctly informed, they want the government to spend more.
Science & Society

Scientists may work to prevent bias, but they don’t always say so

By Bethany Brookshire 3:53pm, February 28, 2017
Scientists may do the work to prevent bias in their experiments — but they aren’t telling other scientists about it, two new studies show.
Science & Society

Analysis finds gender bias in peer-reviewer picks

By Bethany Brookshire 12:30pm, February 3, 2017
The peer-review process aims to avoid bias, but it turns out there’s gender bias in who is picked to review the papers.
Subscribe to RSS - Scicurious