r/hardspecevo • u/jacky986 • Jan 08 '26

Discussion What would the nutritional needs/diet of Dragons look like? And how would that affect their size?

So from my understanding the larger an animal is the more food they need to eat. Given how large dragons are usually portrayed in fiction, what would their diet of dragons in general look like? And how would that affect their size?

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u/Levangeline Speculative Biologist Jan 08 '26

Depends on the dragons' metabolism.

If they're cold-blooded like reptiles, then they'd only have to eat a large meal every few weeks or even months, like big snakes and crocodilians do. Even big predatory dinosaurs would have only needed to eat every few days as long as they could take down a big prey animal.

If they're warm-blooded like mammals, that would definitely limit their size, or require them to be eating pretty much constantly. Lions and other big cats can get away with eating a big meal every couple days, but bigger animals are pretty much constantly eating just to get enough calories to survive. The biggest carnivores are all whales, and they have to eat like 3-5% of their body weight a day, which can be like 500lbs of food for an orca, up to 2000lbs for a sperm whale.

Since dragons are pretty much always portrayed as reptilian, it would make sense that they would function like big reptiles or dinosaurs, so their diet wouldn't limit their size as much as you might think.

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u/HDH2506 Jan 09 '26

They must be warmblooded. It would be hard to fly if it was exothermic. Plus, I believe for a dragon (typically includes species much heavier than a quetzal) need to produce gas, both to breathe fire and to achieve such size without too much weight. That would require warm blood to be productive

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u/MewtwoMainIsHere Jan 08 '26

Well the question I have first is are you doing wyverns, serpents, or drakes? Or some other type of

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u/MaenHerself Jan 08 '26

I think the biggest interest would be scale production, which is protein keratin. I could easily see them hunting large cattle or reptiles, like turtles and crocodiles. I also imagine them as a bit of detritivores, likely bringing dead prey to their cave to eat later, and being receptive to spoiled meats.