How would dragons avoid burning themselves and their habitats?

Over the past few articles, we’ve learned that giraffe-sized dragons could fly with the right adaptations. We dove into what fuel sources dragons could use and how they’d control their flames. We even have some ideas about their diets. Having done all that, there is still one hurdle our firebreathing dragons need to overcome: fire itself.

This is the second of a four-part series on the evolution and biology of (hypothetical) dragons. Each part is a self-contained unit, so you could either read them all or simply dive in where you like.

When you accidentally put your hand on a flame, you don’t need to draw it back. Your body automatically does that for you, before you can even think about it. That’s how naturally averse we are to fire. Living things typically don’t want to be around it. So, how could a dragon stand to have flames streaming through its mouth? To answer that, we turn to aerogels.

Aerogels are porous materials that do an incredible job of restricting the flow of heat. They’re composed mostly of air, which is an awful thermal conductor, and they possess very tiny pores, which keep hot gas from diffusing through them. These properties make aerogels great at preventing the flow of heat via conduction and convection.

If our dragon could produce a natural aerogel coating, it could protect itself from the heat of its own flames. There are even organisms that already produce aerogel: dragonflies!

Dragonfly wings have a structure very similar to that of manufactured aerogel. Scientists even study their growth to make aerogels for insulating houses. Who would have thought that dragonflies would be the key to the biology of an actual dragon?

Now, while it’s all well and good to think about the anatomy behind breathing fire, evolution tells us that adaptations don’t come about unless they help an organism survive and reproduce. For natural selection to produce a real-life dragon, there needs to be some way in which firebreathing is useful.

Breathing fire does have obvious survival advantages. A dragon could use its fire to ward off would-be predators and animals competing for resources. It could also be used to hunt. Like many adaptations, however, breathing fire would come with challenges. Our dragons would need to be careful not to burn down whatever habitat they depended on for food. If they went around burning down huge swaths of land each time they snagged a meal, before long there wouldn’t be anything left for them to eat. After that, no more dragons!

To solve this problem, dragons would need to hunt in places that are rich in prey and highly resistant to fire damage. That’s where prairies come in.

Prairies, also known as grasslands, are the ideal hunting-grounds for a dragon. They actually depend on brush fires to stay healthy. These fires warm up the soil, which increases microbial activity. Microbes decompose dead plants, and release their nutrients into the soil for living plants to soak up. Fires also burn away leaf litter that would otherwise block much-needed sunlight from reaching prairie plants. After a fire, blackened fields are left with the optimal conditions for new plants to sprout up. If it weren’t for brush fires, many plant species couldn’t exist.

As mentioned in a previous instalment, the dragon-like Quetzalcoatlas could travel up to 80 miles per hour(130 km/h) and stay in the air for seven days at a time. Dragons with similar flying capabilities could cycle through many hunting grounds over a vast territory. Doing so would give each individual hunting ground plenty of time to recover from fire damage before a dragon returned. This strategy coupled with how quickly prairies recover from fire damage would ensure dragons didn’t deplete their ecosystem. Instead, they would actually help maintain it.

Dragons could even use their fire-breath to hunt on prairies without driving away their prey. Brush fires cut down the number of trees, woody shrubs, and invasive species on a prairie, leaving room for a lush regrowth of grass. This lush regrowth attracts grazers like bison, which is good for prairies because the grazers moving to a recently burned area ensures that previously burned areas can recover quickly without being mowed down by hungry mouths. Hunting grazers with fire would allow a dragon to influence their grazing patterns and determine where they’ll be in advance. As a result, it could make multiple successful visits to the same hunting grounds while simultaneously keeping those hunting grounds lush and rich in prey.

Grazers like bison would provide an excellent diet for our dragons. As we explored in an earlier article, our Graphene-Crested Skyflame would need an iron-rich diet to produce its fuel, methanol. While meat isn’t the only source of iron for an animal, carnivores consume a lot of easily absorbed heme-iron that would serve a dragon well.

What’s more, bison produce a great deal of methane, which the Skyflame could collect to make methanol. Specifically, the Skyflame could capture bison and keep them in a poorly ventilated space deep within a cave. There, the bison’s methane would be confined and the dragon could inhale it to use for methanol production. This idea fits with the classic depiction of dragons living in caves, which aren’t as far from prairies as you may think.

Shortgrass prairies often form behind mountain ranges, which block rainy weather from reaching them. The ones east of the Rocky Mountains are a good example: lack of rain gives these grasslands a hot, dry climate. A prairie like this would be in close proximity to mountains where dragons could find caves to call home.

The hot-and-dry climate of shortgrass prairies would also make it easier for dragons to use their firebreath to hunt. As previously established, a dragon’s firepower isn’t endless. Megalomethanes, Skyflames, and Wildflowers would all have a hard limit on how long they could breathe fire each day. This firebreathing time limit would vary based on the amount of fuel used in any one fire attack. A hot, dry landscape covered in grass can easily catch fire. A dragon could take advantage of this to trap and kill its prey while minimizing its use of fuel.

Imagine a herd of bison trekking across a prairie. In a group, bison make formidable enemies, and they know it. It’s hard for ordinary predators to separate them — but it’s easy for a dragon. With careful aim, our dragon targets the grass around a few specific bison and sets it alight. The dry grass bursts into flame, creating a wall of fire from which the bison can’t escape.

The dragon instinctively knows it can’t let its prey burn to death. Doing so would destroy its nutrients and produce carcinogens in its meat. Instead, it attacks the bison head on one by one before the fire reaches them. Skyflames would overpower individual bison with their overwhelming strength while Wildflowers would burn them with their unignited acid before attacking up close.

If a Skyflame needs a bison alive, it might be able to pick it up and fly back to its cave — assuming its exceptionally strong muscles and wings are strong enough. Once in the cave, the bison’s methane would struggle to escape the poorly ventilated cavern, making it easy for the Skyflame to inhale for later use.

In addition to bison, prairies provide plenty of wildflowers. In the nectar of those flowers, one can find acetic-acid bacteria as well as the nutrients those bacteria require — both of which can help sustain the Acidic Wildflower’s fuel-producing microbiome.

The Wildflowers could even do some controlled burning across their hunting grounds to enrich the soil and help flowers grow. They could also consume the enriched soil itself, which would also contain acetic acid bacteria. Finally, and most likely, they could consume animals that themselves feed largely on sugary and acidic foods. It’s also important to remember how far our dragons could fly. If there wasn’t enough acetic acid bacteria or nutrients for acetic acid bacteria on prairies, our Wildflowers could just fly somewhere with a great abundance regularly.

Dragons could also use their firebreath in mating. Many male animals engage in physical competitions to demonstrate their vitality to potential mates. This process is known as sexual selection. Dragons could fight for mates using their firebreath in what’s known as intrasexual selection.

Alternatively, they could compete to see who could produce the hottest, brightest, or longest-lasting fire plumes. Being able to produce stronger flames is an advantage that females would want their offspring to inherit. It stands to reason a female would choose to mate with a male that demonstrates the most powerful firebreath. Competitions like these would ensure future generations of dragons possessed stronger firebreath than their ancestors.

In addition to fighting for mates, dragons would likely be very territorial and fight to keep specific hunting grounds all to themselves. Why, you ask? Simply put, preservation. Dragons would need to wait to revisit hunting grounds until they had time to recover from a previous brush fire and attract new prey. If another dragon got there after the recovery but before the first dragon’s return, it would disrupt the first dragon’s rotation between hunting grounds. This would leave the first dragon in danger of starving.

Dragons couldn’t be everywhere at once to defend their colossal territories, so perhaps they could also evolve an instinct to stay as far away as possible from a hunting ground where they had already lost a fight to another dragon. Then, come mating season, they could all migrate to neutral territories, which they would know not to claim for themselves.

What’s next? We’ve talked quite a bit about the various traits and survival strategies dragons would need — but how would they develop these traits and adopt these strategies in the first place? Short answer: evolution by natural selection. For the long answer, watch out for this series’ final installment, Darwin and Dragons, coming out this Friday!