One of the central areas of interest for ZRS is the zombie lifespan.  The theory being that if a rough threat timeline can be established – starting with reanimation, and ending with decomposition – then strategies and expectations can be adjusted accordingly, resulting in countless millions of lives saved.

It’s already been asserted that zombies can only be up and walking in the first stage of decay, known as the fresh stage.  Zombie Lifespan ClockOnce the body reaches the second stage, bloat, the brain has liquefied to the consistency of New England clam chowder.  Unfortunately, because the rate of decay could be significantly slowed in the undead, the Fresh stage may not last just days as in human, but months, years, or even decades.  George Romero’s Land of the Dead suggests as much.

One thing is for certain: If zombies don’t take a considerably longer time to rot than their deceased human counterparts, we may be in much less trouble when the undead rise than originally thought.  Especially if it  spreads very quickly.

Assuming that fresh stage decay takes two weeks to complete, it’s likely that by five weeks after outbreak there would be virtually no more Zombies anywhere.  All you’d need to do is hide out in a safe place with enough food and water for a month, and you could emerge the leader of a new world.

Of course, if you’ve miscalculated and it’s longer, you might just find yourself in a pretty ugly spot once the rations run out and you don’t have an adequate escape plan.

How long do you think zombies last before rotting back into the earth?


  1. Do you know what causes a zombie apocalypse.

    • A virus called MAV it kills people within 24 hrs of infection and then reanimates the body as a mindless flesh eating corpse a.k.a a zombie. This plague has existed for thousands of years.

  2. If zombies do rot, as all shows, comics, etc. shows that they do, it really dues to matter about reanimation or evaporation, dehydration. Eventually, cartilage will decay and the bones will just fall apart which will make them much less dangerous. Think of: “Them bones, them bones gonna walk around, hey! Them bones, them bones gonna walk around!” Watching the beginning of the series over, I did notice the Walkers used to be much more fiesty.

  3. Trying to help you folks here to think outside the coffin. Clearly the virus causing zombyism also leads to metabolic changes such that only unessential bodytissue rots away while there is a slowdown of rotting in the tissue essential for the survival and propagation of the virus. So whatever you think you know about the behavior of dead human tissue is mute as soon as this tissue is infected with the virus. So now the 64000$question: how could this virus potentially evolve to become more efficient with propagation? Anyone up for some zombie sex?

    • You can make up any theory you like as it doesn’t really matter. Zombies live as long as the plot requires.

  4. What about the zombies do they not need food to survive

  5. If the zombies are alive, they could last longer than a couple of months a zombie could live for one to two years. the would most likely die from other diseases since they don’t care for themselves. but if the Zombie virus spreads to all parts of the world, it could be ten years before the whole world is clear

  6. Judging by the success of the first 4-5 years of the series. I would guess the life of the “Walkers” will be another 3 years Therefore the life span of the undead is approximately 7-8 years.
    Although reanimation occurs whenever the living die, the main siege is over and those remaining are already infected, the siege could go on until humanity develops an immunity, or until the scientists develop a vaccine to prevent it.
    As we have never seen a walker “die” of natural causes, the immediate presumption is they can exist a minimum of 5 years. and probably as long as ratings hold up.

    • InfectedGamer98

      actually if you at the timeline of the walking dead right now in the series only 504 days have passed up until the end of season 5 so the walkers will live for at least another 4 years maybe more depending on weather conditions and crossover between states

  7. Reading through most of these replies got me thinking. If zombies are the dead reanimated but are still decomposing, then how can the brain survive longer than a couple minutes? I’ll break it down for ya. I define death as “full body systems shutdown”. If a body can’t become a zombie until it dies (it can’t re-animate until it ceases original animation aka, dies), then the decomposition time is irrelevant. The brain simply cannot function for more than a few minutes without a constant supply of air. And if it’s full reanimation of the body (organs as well as muscle and brain), then decomposition wouldn’t take place any faster than it would for a living being (aging process). Basically, depending on the definition of “reanimation” they’ll either die within minutes of death (I know how that sounds lol), or can continue actively until an outside source intervenes.

    • I forgot to add that I think the main cause of zombie death would be dehydration but then again, realistically speaking, if the virus knows the body has to feed to survive, wouldn’t it also know that hydration is essential too?

  8. Lorenzo Barillas

    The question here, as I think has already been stated in the article as well as the comments, is if the zombie infection deters the organisms that cause decomposition from eating away at the flesh or if the normal rate of decomposition still applies. Separate of course from other factors such as temperature, climate, and terrain to name a few.

  9. You’re all forgetting this thing called evaporation. Zombies drool. That’s a continuous loss of moisture. The sun is relentless. The dry air is relentless. In a week they’d be dried out. It’s simple thermodynamics. End of game.

    • But zombies also eat humans who are stock full of moisture. There are animals who go their whole lives without one drink of water just by getting water from plants and other organisms that they eat. So when zombies eat the flesh of humans they can get moisture from the flesh and/or blood of humans.

      • You’re thinking of very small animals or insects. And with the amount of “food” declining at a precipitous rate plus the constant slobbering and oozing wounds it’s wet to dried out in a week. You can test that by seeing how long it takes for something to dry out outside – and it won’t even be moving.

        Evaporation wins – Zombies loose (or anything else that doesn’t timely rehydrate) – it’s simple physics.

        • Cats don’t need to drink (they still do) they can get all their water from food (if it’s wet).

        • I think that if the water the zombies have to begin with, adding of course the water obtained via other humans eaten, found a way to metabolize into fat of some form (depending solely on how dead the zombies will be), then it is possible that the conflict can and will be very prolonged.

          • OK, so you’ve completely thrown in the towel on evaporation and are now arguing for fat zombies? OMG, and they can also convert this mystery lipid into water to explain all the slobbering which, wait, continues to lose water. OK, that dead ended.

            Here’s what zombies really are. Thanks to South Park we now know they’re really homeless, wandering, panhandlers who will take what you have, make you penniless, and turn you into them.

            Worse, they’re homeless, starving refugees who will devour all your food and leave you in the same state – rapidly approaching death and decomposition.

            And the bullet to the head? It’s code for not leaving any witnesses.

            In the end zombies (or whatever code group is in a similar state) would last days, not months, and not years.

          • I am going to explain this in as simple of a manner as I possibly can to you, since you obviously have no working knowledge of basic human anatomy. The human body is made up of over 90% water. When a human being turns into a zombie (whether via a bite or other means of infection), the water in the person’s body doesn’t just magically turn into drool. It will remain water. Now, my theory is based on the idea that, in all likelihood, zombies are alive and infected with some form of an RNA virus. Therefore, when they feed on other humans, what they digest nourishes their body. This includes ingesting the water from their victim via blood, brain fluid, and other liquids in the human body. And what they ingest, because the zombies aren’t going to be bodybuilding during the apocalypse, will turn into BODY FAT. This is much different from a fat body. With their hunting and stalking of prey, some of the fat will eventually be worked off. This gives them reason to continue to hunt and feed. By those means, the zombie apocalypse would last much longer because the zombies would be living creatures whose nourishment is us. Class dismissed.

            P.S. South Park is a good show for entertainment purposes, but you shouldn’t use it for academic or scientific arguments such as this one.

    • True

  10. it takes six months for the brain to rot

    • That’s not accurate. By the end of the first stage of decay in a human corpse – which can be as short as a week – the bacteria in the mouth has traveled to the brain and eaten it out so much that it oozes out of the nose like mush.

    • No it doesn’t it takes a few days maybe a few weeks for a dead persons brain to rot

  11. Well assuming that we are talking of zombies that are finally killed when they have no brain they must reach stage two. But the passage above is right it could take longer for them to decompose. If that is the case you must also plug in Geographical entities such as hot weather and cold weather. After all of that you must also see if they have a migration, the more they move the more the body of the undead breaks down. Upon factoring all those plus natural decomposition you could look at a matter of weeks or years.

  12. The Iifespan of a zombie would be heavily dependent on it’s environment. One that promotes decay would shorten the ‘lifespan’. The danger is what the zombie can achieve in thatamount of time because for everyone that is newly created, the clock starts over. Also, I have a question as to whether the zombie virus can be spread thru aerosol activities like naplaming an open field of them and the smoke from the burning bodies carry the zombie plaque

  13. I’ts a known fact that part of decay is parasitic life forms (most of them being microscopic) feeding on the rotted flesh of dead things. There is a strong, and common, belief that a zombies brain shuts down (with the exception of the baser functions run by the Medulla Oblongata, or brain stem). The question I propose is why wouldn’t the virus re-activate other parts of the brain and even alter them? The Pituitary gland is a growth hormone producing gland located in the brain with the Hypothalamus connected to this gland. why couldn’t the zombie brain produce an altered version of growth hormones (more of a natural preservative hormone) and have it trickle through the zombies system via a gravity feed type situation.
    This type of activity would prevent cellular decay and since I’m sure even bacteria, or anything with it’s own DNA, (Mitochondria being an exception) would probably do it’s best to prevent self infection and steer clear of trying to eat the infected flesh of any zombie. The lack of anything to help this process, combined with a natural preservative would slowor even halt the ‘natural order’ of brake down.
    Allowing zombies to last much longer then might have been considered possible.

  14. the time span all depends on if the “zombification” process keeps them human or turns them into something completely new but if you look at what some of the recorded outbreaks ZRS has found it would seem like it would have to be similar to the normal human body decay rate

  15. I imagine that a cooler climate would slow the rate of decomposition, but what if the temp falls below freezing? Would the zombie simply lay dormant until it thawed? Or will it continue to try to move, possibly even to the point where it cracks and shatters?

    • I have been interested in this supposed lifespan issue. The books don’t seem to deal with it, at least as a strategy for survival. The critters must turn to soup sometime, and most writers give them substantial decay /rot in a short time. Would be a good topic to play with in a story. I think it’s no mere coincidence that most stories end before the walkers have too many birthdays. Else, must deal with the subject, which could be heresy? Oh my

  16. Does anyone have ever think about rats? what about them, they might spread more the infection, is there any contingency for a thousands army of those attacking a single colony of non infected or maybe immune people? what about other animals, birds, snakes, etc.
    This type of questions might spread and make the infection last for more than we think.

  17. if we assume that zombies follow natural, biological law, then the fundamental “energy in = energy out” law of conservation must apply. any organism must feed in order to carry on the basics of life (or “un-death” as the case may be). that said, regardless of the specific manifestation that a zombie outbreak might take, be it bacterial, viral, or other, without food, a zombie would die within a month or so. if human flesh or brains are the food source, eventually the food would run out. the rate of speed at which people fall to the infection, would determine how long a zombie would last.

  18. I had a zombie dream once where I was holed up in a Home Depot. I used things like muriatic acid and lime to accelerate the decomposition of the shufflers outside by dumping it on them from the roof. Having constructed cisterns to catch rain water and a make shift vegetable garden in the garden center I woke up deciding that Home Depot was a pretty damn good safe haven.

    • acid and lime can be good but i would think they will still be moving so one thing u mmight check is if it might burn through the door they are pushing on caus if so it may endamger you by the ones u didnt dump it on.i too think that it can be a good haven though.but with that said, what do you think there lifespan might be?

  19. Considering realistically, that a zombie was just a psychopathic maniac that was infected by a contagion, instead of litterally undead, i would say a good few months shoould kill all of the zombies, however depending on the contagion, IT could remain on surfaces for potentionally years, this means that litterally ALL surfaces touched by the infected could become transfer methods to the uninfected…leading to a reapeat of the infection cycle, in the event that the contagion becomes airborne, due to decomp. however, all of the non infected would need to follow strict standards to prevent infection (i.e.hazmat/NBC suits, paired with SCBA or a respirator) all bodies should be burned, and decon/protection should be utilized in order to prevent any possibility of infection from aresolized contagion.

    • have been meaning to check out Horde, that’s at the top of my to watch list.No werrios, you aren’t bugging me at all my friend! I appreciate all the recommendations, keep em coming!I’m always looking for recommendations of movies I might not have seen yet that people think I would like or should check out. Thanks so much! Hope you are having a great day.

    • That’s a great point but if they were technically only psychopathic and not reanimated dead, then there’d be no decomposition taking place and the question was about decomposition, not lifespan.

  20. I’ve always supposed that its more bacterial than viral, and as the infection takes hold, the body itself is used more as a scaffolding than the means of locomotion. Each cell being replaced by a bacterial counterpart, with an unknown lifespan. This forestalls decay as the end product is not truly a corpse, but rather a human shaped bacterial composite. Which has an unknown tolerance to environmental factors, as well as the ability to go dormant. This also explains the zombies need to consume living flesh, to feed the colony. Death and reanimation occur before complete assimilation, as the nervous system is replaced first. The infection then moves outward to the tissues, slowing decay by outputting powerful anti-biotic toxins.

  21. I think that however long the zombie lasts before completely decomposing, one should realize that decomposition isn’t the win all that some would believe. A zombie that has decomposed to the point where it can’t move, might very well be able to still bite. Just because something isn’t moving, doesn’t mean that it isn’t still dangerous.

    • So then the more obvious solution would be to wait it out a little more, right?

      I mean that’s sort of the idea, to hide until it’s completely safe!

  22. I think the rate of decay would be in accordance to the region where the zombie outbreak happens. Decay rate in humans very depending on climate conditions, and so would make sense that it would in the case of zombies. Being in an arid, dry and hot climate, say as a desert, the rate of decomposition would be much slower than say in the humid and wet conditions as the rain forest. In addition you would have to take into account the time of year, winter or summer, can also play a huge role in preserving or hastening the decomposition rate.

  23. True zombies should not differ from a regular corpse by much, but the factor still lies in the virus itself which is a great example made. like an opposite effect of leprosy or the black plague (the decay and formation of skin legions). it also relies in the climate people live in. a zombies decay rate is judged by how hot and how cold it is, one could easily live twice if not 3 times as long in the upper north as to one futher south, cooking in the desert sun like bacon in a pan

    • but you got to remember even if it is colder states that they can live longer they will be less mobile in those states. and i think that the infected can last anywhere from 1 to 3 year span aas long as they are like you said in colder climate it may be 3 year cause the virus will surely affect the bacteria that is responsibel for decay and there is no insects. plus the decay will differ from that of a corpse simply cause it is in motion and upright unlike the corpes so none of the bugs will be on it as much.

  24. A zombie might last about 3-5 years depending on how long it takes to completely turn to bones Or at least till it becomes a nearly harmless threat.
    “Infected” however, would probably live about one or two months before dying, unless a series of intense efforts were taken on some groups part to keep a series of them infecting, spreading and being fed in a controlled environment.

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