Vampirism: Behavioural Ecology and Evolutionary Biology
See my Masterlist for my other WIPs
See my BFTI intro post for more about this wip.
See my Vampirism post for the rest of the speculative biology on this disease.
So, now that I've touched upon various things relating to all the components of a disease model that I'd like to include in my own version for vampirism as a disease, I'll do a brief recap with the main takeaways:
The idea of a retrovirus that causes 'vampirism' as such having been assimilated at some point into the human genome, having gone dormant and become an endogenous retrovirus (ERV) -which also ties in directly with the genetic susceptibility, since it's been around in the human genome for ages, and thus possibly also suffered changes in expression and such.
The idea of a prion-based disease that functions as a trigger for the dormant vampire ERV (V-ERV?).
The idea of a fungal infection or fungal endosymbiont that regulates or modulates the progression of the virus as a secondary or tertiary infection. Basically meaning that it determines just how far the vampiric changes affect someone.
There's various aspects to consider then in order to round out this whole idea of a multi-layered disease model for vampirism. In that sense I wanted to take a look at all the factors that'd influence how this disease works, and that can be broken down into the main aspects of behavioural ecology and evolutionary biology (aka how does the disease actually work, what does it do, what are its effects, and how would that work in practice when it comes to evolution and its mechanisms):
How Genetic Susceptibility Applies to Vampirism;
Evolutionary Justification for Vampirism;
Feeding Behaviour and Feeding Efficiency
Monstruous Physical Trait and Behavioural Adaptations
Evolutionary Stability and Long Term Selection
Viability: Could Such a Complex Pathogen Naturally Evolve?
These will be explained below the cut.
1. How Genetic Susceptibility Applies to Vampirism
When trying to concoct a biological vampire disease, I could use genetic predisposition in different ways:
Selective Infection – Only those with a certain gene (like a receptor protein) can be infected, creating "chosen" vampires.
Different Outcomes – One person might become a strong, intelligent vampire, while another suffers horrific mutations based on their genetics.
Carrier vs. Full Transformation – Some people could be asymptomatic carriers, while others fully turn (like Typhoid Mary but for vampirism).
Vampire Bloodlines – If the prion or virus is passed genetically, it could create ancient vampire dynasties, where only certain families can transform.
This made me want to combine some of elements elaborated on above. I'd like a believable biological origin of vampirism that makes sense in an evolutionary context. Vampirism wouldn't be widespread, because that simply wouldn't be sustainable in an evolutionary context when it comes to predator-prey interactions. Having that many apex predators would unbalance the ecosystem, and like many of the highly contagious and lethal disease like for example Ebola it’d burn itself out before it had the chance to spread far and wide. So, it'd have to take into account how many humans a single vampire needs to feed on in order to survive. Of course there's context-dependent aspects, like whether they can feed multiple times from the same person (which would require either consent or enslavement and keeping them alive) or whether they feed and kill. I'm a biologist, and want to have it make sense when it comes to evolutionary ecology. What would their territory size be, how they'd interact, form groups/packs/covens vs remaining solitary, etc. I was thinking perhaps the junk DNA in humans contains some genetic aspect that determines whether a person is susceptible to being turned into a vampire, which could meld well with both the prion-based variant or the retrovirus theory.
I also want vampires to be.... quite animalistic, here, or at the very least monstruous, not the more modern stereotype of handsome/charming ones that look completely human. If they do end up with more unsettling physical characteristics, perhaps they'd also have some sort of defence mechanism that either tricks humans into not noticing these more disturbing aspects of them (in some literature vampires have 'glamour' where they basically enchant/hypnotise people into doing their bidding), and I’m wondering if there's any biological precedents for that, like pheromones or something that'd cause a similar effect.
Vampires are also often considered 'undead' or they die and come back as vampires. Cordyceps (fungi) also invade their hosts until they take them over. Are there any other diseases or biological processes which would explain the 'undead' part? There could be some animal or insect or other organism that doesn't have a heartbeat, or warm-blooded vs cold-blooded organisms, or maybe some species that have an extremely low resting heartbeat so it'd be easy to mistake them for 'dead'?
Selective infection and different outcomes are possible when it comes to biologically accurate vampirism based on genetic predisposition. In an evolutionary context the ones that would turn into horrific monsters (mindless, feral) wouldn't last too long, and it'd be the more controlled vampires that live on longer, thus possibly also resulting in positive selection when it comes to evolution. However, if it's indeed a virus or prion disease, and one of the effects is longevity, then the changes would be quite slow over time, since selection happens under pressure and if technically they'd live almost forever then it wouldn't make sense for the virus or prion disease to change very quickly over time.
2. Evolutionary Justification for Vampirism
For vampirism to persist in an evolutionary framework, it kinda has to provide a reproductive advantage and not burn out due to overpredation. Some key factors to consider there would be:
Population Control → Vampires must remain rare apex predators to avoid ecosystem collapse.
Energy Efficiency → A vampire must extract maximum energy from a blood meal, so feeding too often or inefficiently would be costly.
Social Structure → Some level of cooperation (packs/covens) may improve survival, but competition could drive them into a more solitary, territorial existence.
To justify the rarity and monstrous traits you want, a combination of genetic predisposition, a slow-burning prion-like disease, and a retrovirus component might work best.
How This Could Work Together Evolutionarily?
The retrovirus is an ancient element that’s been a part of the human genome for millennia, possibly even from a time when early hominids encountered a fungal infection, establishing a long-term symbiotic relationship.
The prion infection is the trigger—when it activates the retrovirus, it reactivates the dormant fungal symbiosis, leading to the vampiric transformation.
Selective Pressures: Over generations, individuals who were genetically predisposed (i.e., had retroviral DNA) survived, with the retrovirus possibly providing benefits like increased resistance to certain diseases or enhanced longevity (what if it's an innate part of our immune system?).
However, not everyone with the retrovirus would transform. Only those with the right combination of viral genes and environmental exposure (such as the prion trigger) would actually experience the transformation. This keeps the vampire population rare and makes the prion disease serve as a selective force.
3. Feeding Behaviour & Energy Efficiency
This is more about the behavioural ecology of vampires, because I got side-tracked by the idea of how this would work when it comes to predation upon humans. One of my main irks in some vampire literature is that they completely disregard any realistic depictions of vampires as predators by means of how they feed/how often they feed. I was watching Castlevania and liked the idea of basically farming humans lol, sue me. For vampires to be ecologically viable, they must have an energy-efficient feeding strategy:
Feeding Frequency:
Small vampires might need to feed weekly, while larger ones could go months without blood (like some snakes).
The fungal component may allow a vampire to enter low-metabolic stasis to survive famine periods.
Feeding Strategy: Multiple Small Meals vs. One Fatal Attack
If feeding is sustainable, vampires would prefer "blood farming" (keeping humans alive and feeding over time).
More monstrous vampires may be opportunistic hunters, killing and draining victims quickly.
Territorial Range & Population Density
A single vampire would likely control a range of 50-100 square miles, depending on prey availability.
Urban vampires might form small covens (like predator coalitions in big cats) to manage their hunting grounds.
Solitary vampires would dominate in rural areas, ensuring no competition.
Now, I wanted to get into what my vampires would actually look like. I wanted my vampires to be quite feral, and inhuman (think Nosferatu rather than Twilight), and how that would work from a biological perspective. So, my vampires are visibly inhuman, with some biological adaptations for efficient predation.
Physical Changes (Driven by the Prion & Fungal Symbiosis)
Extended Jaw Structure: Some real-life mammals (like the goblin shark) have extendable jaws—this could allow vampires to have an unsettling, retractable bite mechanism.
Bioluminescence/Pheromone Emission: Some deep-sea fish use biochemical signalling to attract prey—a similar mechanism could explain the "glamour" effect, releasing airborne pheromones that make humans more suggestible. I need a mechanism that makes people just ignore the fact that they're the epitome of uncanny valley 'something is off'.
Reflective, Non-Human Eyes: Many nocturnal predators have tapetum lucidum, increasing night vision—this could explain glowing/red vampire eyes.
Digitigrade or Elongated Limbs: Enhanced speed could be achieved with digitigrade limb structure (like a werewolf stance), making movement eerily unnatural.
Pale, Translucent Skin: If vampires avoid UV light, they may lose melanin over time, appearing ghostly white or bluish.
5. Evolutionary Stability & Long-Term Selection
Now, I'm a biologist at heart, and all this talk about vampirism as a disease and how it'd change people raised the question as to how it would actually evolve over time. Seeing as vampires are often depicted as being functionally immortal, or undead, there were some evolutionary aspects to consider, and what would be needed to keep vampirism circulating throughout history without vampires going extinct or them over-hunting or eradicating humans.
Slow Evolutionary Pressure:
Because vampires don’t die easily, the disease would change very slowly.
However, new mutations could arise if vampires interbreed with asymptomatic human carriers.
If different vampire variants exist (feral vs. intelligent), natural selection would favor controlled, calculating predators over mindless beasts.
Rarity of vampirism:
The infection has a high failure rate—most people who contract it either die or become feral.
Controlled vampires may actively kill off weaker, feral vampires to maintain balance.
Survival strategy: Vampires who "farm" humans would have a higher evolutionary advantage than those who kill indiscriminately.
6. Viability: Could Such a Complex Pathogen Naturally Evolve?
So, that brings me to the last point: how realistic is all this? I've put a lot of time and thought into it, and there's definitely a lot to be said for this multi-layered disease model of vampirism, but it's also a delicate balance between cool worldbuilding and unbelievable, so I wanted to look at from an evolutionary perspective, and how realistic all these components really are. This is basically the summary of the previous posts and highlighting the relevant aspects.
Natural Evolution: Extremely Rare, But Not Impossible
While unlikely, there are real-life cases of multi-layered diseases, and disease models with complex interactions, and such a layered pathogen could emerge under specific conditions:
Ancestral Retrovirus: Humanity already carries ancient viral DNA (8% of our genome is viral remnants).
Fungal Symbiosis: A fungus might evolve to exploit humans via neurological or metabolic hijacking.
Prion-Like Spread: If a misfolded protein gave survival advantages (like extreme metabolism or sensory enhancements), it could be naturally selected over millennia.
Such a hybrid infection could arise through:
Zoonotic Jump → A fungal pathogen from bats or deep-sea creatures gains human infectivity.
Symbiotic Evolution → A pre-existing human retrovirus interacts with an opportunistic prion or fungus.
Artificial Engineering → A secret biological experiment leads to a perfect apex predator.
Real-World Precedents for Complex Pathogen Interactions
There are definitely a few real-life examples that suit my needs.
Endogenous Retroviruses (ERVs) → Ancient viral DNA can still influence human biology & immunity.
Fungal Pathogens in Immunocompromised Hosts → Many fungi thrive when the immune system is weakened by HIV, chemotherapy, or genetic disorders.
Prion Diseases in Isolated Populations → Diseases like Kuru spread through specific cultural practices (cannibalism).
Evolutionary Justification for Vampirism
If vampirism evolved gradually, it would be:
A rare, symbiotic disease that only affects genetically susceptible individuals.
Sustainable, as it alters host metabolism, preventing overfeeding.
Naturally selective, favoring those who adapt (cognitive vampires) over feral ones.
Aposematism is when a poisonous or otherwise gross/ dangerous/ unprofitable species uses pretty, bright colours (or some other noticeable signal) to warn predators “Do Not Eat!”
Unfortunately, many predators are not born knowing this, so they generally have to learn through trying something new and having a very unpleasant experience!
AKA: aposematism (usually) relies on predator learning!
1. when you copy something, but like, aggressively.
2. a form of mimicry in which predators resemble a harmless or desirable model in order trick prey into overlooking or even approaching the predator.
Basically: this fly is pretending to be a bee, so that a real bee will see it, think “oh that is just a fellow bee!”, and carelessly approach the fly, at which point the fly will ATTACK and eat the bee. This is bonkers to watch.
Maybe not everyone shares the same excitement that I have for plants, but would you change your mind if I told you that plants are a lot more like us than you think?
According to Monica Gagliano and colleagues from University of Western Australia, plants potentially have the ability to learn through association!
Many studies on animal behaviour have shown that animals can associate conditioned and unconditioned stimuli through training. Pavlov’s dog is the most famous example of this! But Gagliano’s group used peas to show that plants have this ability too!
Plants need food just like animals do, except food for plants is light. And just like foraging animals, plants are able to detect and move towards the light through phototropism.
These scientists wanted to know if plants can associate this unconditioned stimulus (light) to a neutral conditioned stimulus, wind from a fan, to see if the plants can learn to associate the two positively or negatively.
And guess what?
Peas that were trained to associate the two stimuli positively grew towards the wind even without any light, and peas trained to negatively associate the two grew away from the wind!
The group also found that this association was only made during the day, because that is when light is normally present for the plants. This shows that plants can learn based on their circadian cycle (yes, plants have them too!) to optimize food intake.
This is not only super cool information, but can actually help us understand more about how plants can survive and evolve under harsh, low light conditions. It opens up new doors for research in physiology and mechanisms allowing this sort of associative learning in plants, which also may not be too different from animals.
If this doesn’t spark your interest in plants, I don’t know what will!
Would you believe me if I told you that the little creatures living in the soil can save our world from starvation?
Yes, it is a bit dramatic, but with the ever growing concern of unsustainable agriculture, a group of researchers from Zurich have thought long and hard about the possibility!
The group, led by S. Franz Bender, argue that integrating a large diversity and complex community of soil microbiota into crop systems can help mitigate the damage of harsh agricultural practices. They explain that the ability of soil bacteria, fungi, and insects to provide “services” to the plants, such as converting soil compounds into accessible nutrients and recycling nutrients back into the soil, can be used in large-scale farming for sustainable crop production. They also mention that species quantity is not the only important factor, but the type of species and their roles in the soil can also impact effective crop production.
Although this idea sounds promising, some in the scientific community were not entirely convinced. A response to the paper by Anderson A.S. Machado and colleagues from Berlin argue that introducing a diverse group of soil organisms to controlled agricultural systems can have negative consequences. Their main concerns involved potential health risks for humans in terms of release of compounds by some microorganisms, and environmental concerns such as eutrophication.
From my perspective, both papers argue their sides effectively and they ignite the path for much needed research in the idea of “ecological engineering”. They both show that there are significant gaps in knowledge in terms of community-level ecology, and potential evolutionary consequences of introducing naturally occurring soil organisms to extensively genetically modified crops. From my knowledge, microorganisms and plants have genotype x genotype interactions, meaning there is a genetic basis to their interactions, which can also have an impact of this idea.
Nonetheless, I am sure we can all agree that no idea is a bad idea when it comes to preventing our progeny from going hungry. Perhaps our little friends in the dirt will end up saving the world!
HEY! I hope you enjoyed reading this blog as much as I enjoyed writing it. If you are interested and have the time, definitely read through the two papers I talk about, they really made me think!
As always, please reblog and share this post for others to check out. And PLEASE follow my blog for more!
- P
Sources:
Bender, S. F., Wagg, C., & van der Heijden, M. G. (2016). An Underground Revolution: Biodiversity and Soil Ecological Engineering for Agricultural Sustainability. Trends in ecology & evolution, 31(6), 440-452.
Machado, A. A., Valyi, K., & Rillig, M. C. (2016). Potential Environmental Impacts of an “Underground Revolution”: A Response to Bender et al. Trends in Ecology & Evolution.
