The Zombie Anatomy: How to Kill the Living Dead
On the inside, we’re all made of the same icky stuff. Zombies too.
What’s fascinates me about zombie mythology — and pathology, while we’re at it — is how these stories strive for at least a tentative grounding in actual science. Especially in recent years, the zombie narrative comes hand-in-hand with mentions of ‘viruses’ and ‘infections’ that don’t adhere to real-life virology, but a dash of pseudoscience never hurts.
And let’s not forget George A. Romero’s 1968 hit Night of the Living Dead — the widely-accepted source of modern zombie canon — which attributed the zombie brain mutation to radiation from Venus. Sigh. But there’s a consistent thread here, no matter which corner of zombie myth you explore: something bad infects your brain.
And this makes sense, at an instinctual level. Zombies look like humans but they behave differently, and for obvious reasons, behavior = brain. Pseudoscience at it’s finest. Night of the Living Dead wasn’t the first zombie story to make this connection, that honor goes to the 1955 thriller Creature with the Atom Brain, but Romero’s masterpiece took this logic one step further:
“The Survival Command Center at the Pentagon has disclosed that a ghoul can be killed by a shot in the head, or a heavy blow to the skull. Officials are quoted as explaining that since the brain of a ghoul has been activated by the radiation, the plan is: kill the brain, and you kill the ghoul.” — Newscaster, Night of the Living Dead (1968)
“Kill the brain, and you kill the ghoul.” Such Perfect prose, no wonder it stuck around all these years. Over time, though, this trope evolved into what we know today: the only way to take out a zombie is to get to the head. Anything else, like blows to the heart or the guts, or other typically-fatal trauma like electrocution or sometimes even drowning, just won’t do the trick.
And that seems wrong.
Shouldn’t there be more ways to take down a zombie?
First things first, let’s accept this rule that “behavior = brain,” because generally that’s a pretty spot-on correlation. Zombie brain infections aren’t unheard of to biology, especially in the insect kingdom, and are known to be caused primarily parasites, bacteria, or viruses. One of today’s most hip zombie trends — the Ophiocordyceps fungus — causes infected insects to climb upwards to the highest point available before their gruesome demise. And, of course, it targets the brain and nervous system.
A zombied body still uses its brain to coordinate muscles and find other vulnerable individuals to infect, but that’s about it. All other instincts become either numbed or completely erased; there’s no sense of emotion or self-preservation, only the hunt remains. This is why — as per the mythos — that traditional methods of incapacitation won’t work against the zombie horde. Pain doesn’t register to a zombie like it would to a living human. The only proper method to kill the walking dead is to target the one thing that actually makes it a zombie: the infected brain.
Or so we’ve been lead to believe.
The brain itself is made of many complicated parts, each doing many complicated things. The first I’d like to call out is the brainstem, responsible for critical muscle coordination of the heart, lungs, and a whole slew of other functions that keep us alive. The brainstem has been identified by members of the Zombie Research Society (because of course that’s a thing) as something called an “instant-kill.” Makes sense.
But other segments of the brain aren’t as critical to the undead. The forebrain (aka the cerebrum) serves an entire different set of functions, mainly “reason, planning, memory, and sensory integration,” as well as conscious thought. So, basically, all the things that a zombie doesn’t need, although the case has been made for zombies requiring a sense of smell to find food, but I wouldn’t consider that necessary to survival. It’s just a perk.
For humans, damage to the forebrain is severe and often life threatening due to the complex and highly-integrated necessities of our nervous systems. Zombies, it’s theorized, may be hindered by damaged to the forebrain but not necessarily put down for good. Not all headshots are created equal.
So humans need their forebrain and brainstem to survive, but zombies can do just alright (mostly) without their forebrain intact. Interesting. Perhaps if we started to keep a tally on what organs are unnecessary to zombie survival, compared to humans, we might see something like this:
But there’s more here to unpack. The human body — organs, muscles, cells — all operate given a specific set of rules. Even though zombies operate differently, some of those rules still apply.
For instance, all living things need oxygen to survive. There’s this handy thing called cellular respiration that creates energy from sugars and oxygen molecules, and that energy, ya know, keeps us alive. There are indeed methods to create energy without oxygen, but in humans that results in a painful buildup of acid in muscle tissue. So why is this relevant? Well zombies need energy too, and as long as they’re dependent on respiration, that requires oxygen delivered to cells by the heart and lungs.
See where this is going?
If the heart or lungs of a zombie — or the supply of blood left in their circulatory system — are severely damaged and can no longer deliver oxygen to cells, then the zombie is pretty much kaput. And actually, a lack of oxygen can be even more damaging to (you guessed it) the brain. Anoxic brain damage can occur within just four minutes of oxygen deprivation, beginning with hemorrhaging and swelling before the brainstem herniates through the skull. Grewsome.
So sure enough, it’s not just the brain that’s a zombie’s weak point. Just like in humans, critical damage to the heart, lungs, or major veins and arteries will all take down the undead eventually. And the list certainly goes on:
I usually forget about the liver, but as I was recently told by a relative who’s practically a doctor: “Don’t.”
The liver’s job filters out harmful toxins from the body’s circulatory system at an astounding rate of 1.5 quarts per minute. These filtered toxins include foreign substances (like alcohol) as well as naturally-occurring chemicals that the body produces everyday, like ammonia, which are incredibly hazardous in large quantities. Humans are actually able to live up to a year without a liver under the right circumstances, but an undead zombie body is a different case. Decaying animal flesh produces incredibly large volumes of ammonia, as well as a slew of other toxic chemicals, and the harmful effects of liver failure would be seen much more quickly.
The result is something called hepatic encephalopathy, which damages (yup) the brain. It might not be as immediate as a blow the brainstem, but without a liver, a zombie’s blood would become toxic in just a few days, maybe even hours.
As we keep stepping down the body, we hit the kidneys. Remember those toxins that the liver filters out? Well it’s the kidneys that finally push those toxins out of your body. Without both kidneys, and without proper treatment, humans would have a tough time surviving for more than a few days. But you’d need to take out both; humans (and presumably zombies) can live with just one kidney intact, but the renal system overall is pretty darn critical to survival.
The digestive system as a whole (which I’m just calling guts for the sake of time) is a big target on a zombie’s body, but one that they’d likely be able to survive without. The same goes for humans, and actually in cases of stomach cancer, entire segments of the gut can be removed without long-lasting damage.
The next case is an interesting one: muscles. Clearly having muscles is not pivotal to staying alive as a human, but damaging muscles is a different case, and one that would be pertinent to fending off an incoming zombie horde. When muscles are crushed, they risk releasing high volumes of potassium into the circulatory system. Unless this chemical is filtered out by the liver and kidneys, it can actually be incredibly fatal. Potassium injections are used in executions to stop the heart.
Also, the whole essence of a zombie is to walk around slowly, finding new victims. Remove the zombie’s ability to move and you’ve got a fate worse than death. I’m counting this one as fatal.
Last on the list is skin, which is another fascinating case. The primary function of this organ (in terms of survival) is to protect against pathogens and infection, but for zombies I’d wager we’ve gotten past the point of no return on the infection front. Instead, it’s actually the pain of skin damage, like burns, that is worth noting. Because the hijacked zombie’s nervous system will ignore all pain signals, they’d be fine. That’s hardly the case for humans, though. Under certain circumstances, extreme pain can result in circulatory shock, which is indeed deadly. Count this one as fatal for us, but not the walkers.
This is a good note to end on, because this variability of pain thresholds is the most significant — and concerning — factor when defending against the walking dead. Most of what incapacitates humans isn’t an immediately deadly blow to a critical organ; we tend to shy away once something hurts us. I’ve been taken down by a splinter before, and I’m certain it’ll happen again.
Zombies don’t work like that. Something immensely painful to humans, like extreme heat or cold, or an extremity gunshot, won’t do much to slow down a zombie. The infected brain has shut down those sensory impulses in favor of one single driving prerogative: spread that damn infection.
But take solace in this: it’s much easier to ‘kill’ a zombie than most of our fiction would tend to suggest. The brainstem is a reliable target, and even if the forebrain isn’t instantly fatal, a gunshot to the head will pretty much explode the entire organ. If you want to aim for a bigger target though, the chest cavity would be a reliable place to start too.
And the list goes on. Crushing blows to muscles can result in cardiac arrest, and the same would go for electrocution too. Slashing veins and arteries would bleed a zombie dry, and just like drowning, would cut off oxygen from the brain and cause fatal hemorrhaging. So don’t be too worried about the zombie apocalypse; the undead are almost as fragile as we humans are.
Or, you know, you can take the zombie off dialysis for a few days. That’ll do the trick too.
