Natural Selection During A Zombie Apocalypse
Recently I had possibly the nerdiest conversation of my entire life. I woke up at 5:30 am because River (5 months old) thought it was morning. My brother-in-law, Brian, happened to be online and started the conversational seed to massive nerdery: October, Halloween, horror movies, and some zombie comics he has been reading. Also, I’ve been very entertained by, and currently in the middle of, Richard Dawkins’ new book The Greatest Show on Earth.
As I typed out the next sentence that my brain formed, I knew I was diving in to nerdom deeper than I had ever ventured:
(06:11:38 AM) Ryan Hadley: I wonder what a constant zombie presence would do for natural selection
(06:11:52 AM) Ryan Hadley: holy shit I’m a dork
Before I get in to my thoughts on this and dive even deeper in to this nerdery, I must admit some major faults of mine on this subject:
- I am not an expert in any kind of way on evolutionary biology. I do feel I have a better understanding of it than your average Joe in the USA. But, this is only because I understand that it is real, a fact, and not random. Three things it seems we often get quite wrong. So my guesses on what a constant zombie presence would do are quite limited by the fact that I am not a scientist.
- I am not an expert in any kind of way on zombie mythology. There are quite a lot of details and opinions out there on zombies. I have not looked in to it far at all. 95% of my knowledge on zombies comes from Shaun of the Dead. The other 5% comes from various other means of hearing about zombies: video games, word of mouth, movie reviews, etc.
I’m thinking only of the case where zombies have flourished over a long period of time. Many human generations. Many years, decades, of a constant, never ceasing and highly dangerous human predator. The humans lost the war and the zombies are prospering.
First, some thoughts on the changes to the environment:
- Society as we know it would not be able to survive.
- Sustenance would be rare and dangerous to find.
- Life expectancy would drastically plummet.
- Communication/contact with other humans would be rare. I’m thinking multiple groups of survivors would just have to do their best on their own.
If my assumptions are correct, there would be multiple pools of people quite possibly evolving in vastly different directions. What directions would be likely? Let’s take a look at the predator:
- Extremely hard to kill.
- Usually hunts in large packs.
- Never sleeps, always hungers for your flesh and braiiiiiiinz.
- Very slow.
- Very dumb.
- Main method of attack: powerful bite that breaks the skin. One successful bite and you’re lost.
So, keeping in mind the other environmental changes, what are some human traits that could offer a higher chance of surviving?
Quickness/Endurance
Being slow will just get you eaten. You have got to be able to move quickly and not stop too much to catch your breath. I can imagine it helping in more than one way:
- Escaping a surprise zombie ambush.
- Being able to get to resources needed for sustenance/protection and get back to safety without being ambushed.
- Being able to get to resources needed and safe areas before other humans do.
Obviously, most of the old and crippled would not survive long during the early years of the initial outbreak. The overweight are typically slow and have little endurance, so they too would be easy targets in the first years. After the first years, most of the survivors would most likely be the younger, quicker and more physically fit of our species.
After the first couple of years there would have to be a trade off. Sure, the quicker/fitter are now the ones breeding, but resources would be scarce. If you need more fuel for your body than someone else, you would probably have a harder time surviving. There would have to be an equilibrium of fuel needed to physical agility. In areas where sustenance might be easier to find, those groups of survivors would probably also be more evolved in quickness and endurance.
Reproduction
With a drastically shorter life span, the women and men who become parents will be younger and younger. The age at which women reach sexual maturity would start to drop. Having kids young would be preferred, since you most likely won’t be alive past 30 to help raise and train your kids with your zombie surviving knowledge.
Also, possibly the amount of time of gestation could start to shorten. Mothers who give birth to smaller, but still healthy, babies earlier than 9 months would probably find it easier to survive. The births would be less complicated if the baby is smaller, and getting around (fleeing zombies) would be quite difficult for a 9 month pregnant woman.
Maturity
In our society now, kids aren’t considered “ready” to be on their own until around age 18. And even then many kids still rely on their parents through college. This would not do in a long term zombie outbreak. Babies would have to be born early in the mother’s life (as mentioned above), and the babies would need to be self sustainable much earlier than 18.
Our rate of maturity would most likely increase. We would go through puberty at younger ages and we would finish “growing” at younger ages. All to be a contributing member to the tribe faster, instead of requiring more effort from the tribe to raise you.
Natural Zombie Defenses
What if you happened to be ambushed by a zombie and survived a close encounter? Maybe the zombie actually tried to bite you, but wasn’t able to break your skin? I could imagine skin thickness possibly being good for surviving zombie attacks. Maybe not quite to the extent of being able to flee though. So maybe not. But just a thought, perhaps enough quick survivors who also happen to be able to survive some zombie bites would nudge natural selection in the direction of increasing skin thickness.
Immunity
What is it about a zombie bite that kills? Is it possible that some day in the long zombie infestation someone has just the right genetic mutations to be able to not die from one bite? This would be huge. Their tribe clearly would have much greater chances of surviving. They would have more options open to them for places to travel to, places to find sustenance, and — they would be the perfect evolved group to start staging a counter attack on the zombies.
Zombies wouldn’t be harmless. I mean, they’d still be damn hard to kill and the right bite in the right place could be quite fatal. But they wouldn’t be feared nearly as much by these people. They wouldn’t be “one bite you lose”. Which is huge.
In Conclusion
We would be alive, there would be survivors. Multiple independent groups. We would be reproducing and natural selection would be continuing to make us properly fit our environment.
Zombies would be dead. They are the walking dead and are damn hard to stop. They would survive by “infecting” our weak and because of their insanely long “life” expectancy.
We’d have the advantage, because of natural selection. We would be near powerless at first, but because we are alive we would adapt. Eventually the tides would turn and we would be able to best the zombies, who are dead and don’t adapt, who once bested our distant ancestors.
In the case of a zombie apocalypse, natural selection would be our only hope.