Fantasy world biology and parasites, Part 1.

It’s no secret for those of you reading From Winter’s Ashes or following Laika Dosha, that I like worlds that respect logical conclusions.

I come from a reading background of bleeding-edge hard science fiction, so it often gives my ideas in a fantasy world a different lens. Today, we’re going to talk about parasites in a fantasy environment.

  1. Cordyceps. Fungal hacker extraordinaire. Most famous for hacking ants to climb to high places (in unsurprisingly consistent light/shade and humidity conditions), lock their jaws to a plant, and conveniently die in a way that makes spores most viable and likely to find new hosts.
    1. Unicorns. What a great host horses would make. Gregarious herding animals, and highly mobile. But complex brains means complex behavior patterns, and the herky-jerky poorly coordinated movement of a horse infected with a fungus would mark it quickly for herd exclusion by the species, and by predators for an easy meal. So an intermediate host is best. Why virgins? Who loves and adores horses more than a little girl? So she rubs the unicorn’s horn, and later at home pets her family horse, and wishes she had a pet unicorn instead. She gets her wish. It does not end well for the horse.
    2. The first wizard to find a dragon that has succumbed to cordyceps makes his riches by selling the spores to the kingdom’s treasury…
  2. Toxoplasma Gondii. Now here’s a scary contender. Amoeba skilled at hacking prey animals into getting eaten by their predators. Incredibly good at infecting warm-blooded animals of all kinds! And really, really good at hacking their behavior.
    1. Dragons. Did it ever strike you that dragons expending that much effort and danger to attain gold seemed like an incredibly bad payoff for a K-selector species like a dragon would have to be? (All large terrestrial predators are.) Sure, Bowerbirds assemble an impressive hoard of shiny things to attract a mate, but their shiny things aren’t defended by a hostile species with lots of weapons and centuries of martial tradition.
    2. So, let me propose this for your fantasy world: Toxoplasma Draconis. Dragon eats foolhardy Knight who was a little twitchy that day, his timing was off on his sword-swings, his shield-work a little slow and sloppy. Easy prey.  Knight is carrying Toxoplasma Draconis, which uses dragon’s digestive system for the sexual reproduction stage of its lifecycle. And while its at it, it hacks the dragon’s nervous system to set off a Bowerbird-type instinct. Gather all the shiny things. Knights come to kill dragon and get gold, get eaten instead. More Toxoplasma joins the gut-orgy.
    3. Dragon flies around, poops, and Toxoplasma oocytes get everywhere. Rain washes them into streams and ponds. Livestock and humans drink water, infect the mammal, and hack its nervous system to drive it up to high elevations where its easy picking for a dragon flying by.
    4. Eventually a Knight comes along who isn’t twitchy, whose sword-swings are well-timed, and his shield-work impeccable. Because his nervous system isn’t a mess of encysted Toxoplasma. He slays the dragon, and ceremonially eats the heart for power.
    5. Oops.
    6. Months later, our now-twitchy knight is eager to hunt his next dragon. Sure, his shield-work has gotten a little sloppy, and his sword-swings aren’t so well timed, but he’s sure it will go just as well as the last one… (it does not).

Got any parasites you want to add to the discussion? Comment below and I’ll work them into Part 2.


One thought on “Fantasy world biology and parasites, Part 1.

  1. Wolbachia bacterium might be of interest. They infect insects.

    Wolbachia maximize their spread by significantly altering the reproductive capabilities of its hosts, with four different phenotypes:
    Male killing: infected males die during larval development, which increase the rate of born, infected, females.
    Feminization: infected males develop as females or infertile pseudo-females.
    Parthenogenesis: reproduction of infected females without males. Some scientists have suggested that parthenogenesis may always be attributable to the effects of Wolbachia.
    Cytoplasmic incompatibility: the inability of Wolbachia-infected males to successfully reproduce with uninfected females or females infected with another Wolbachia strain.

    More here:
    Making species female-only (

    A human Wolbachia strain might be the origin of Amazons!

    Liked by 1 person

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