What Will Happen To The Zombies When All The Humans Are Gone?

29 Apr

Imagine the zombie apocalypse has come and the last living person (or uninfected human depending on your preferred zombie scenario) has just been consumed; humanity has gone, or at least that’s how it seems. This is where most tales of the undead would end. However, I’d like you to take a moment to think about what would happen next. That is, what would happen on planet Earth after all those we’d recognise as humans are gone and all that’s left is the zombie horde? There’s two possibilities, one is obvious while the second, more interesting one, is not.

The obvious possibility is that the zombies will simply disappear once the last of their preferred human prey have been consumed. This may happen quickly if the zombies are living people infected by some sort of disease that makes them act like zombies as they starve to death, or slowly if they are the more traditional, risen-from-the-dead zombies that will gradually rot away and turn to dust. Once this happens, the Earth will undoubtedly pick itself up, shake itself off and set to work recovering both from the effects of the zombies and, indeed, the brief blip (geologically-speaking) that was human civilisation.

The world might one day see intelligent life again, but this will have to wait until a new species evolves to fill the void left by the end of humanity and because of the way evolution works, it’s far from certain that this will ever happen. If it does, these new intelligence beings may one day find traces of humanity and wonder who or what created them just as Europeans did when they first discovered the ruins of ancient Mesoamerican cultures deep within what they assumed were pristine rain forests. Where would these new intelligent beings come from? Well, that’s hard to predict. It could once again come from our own great ape lineage, maybe the bonobos or the orangutans, but it could also come from our more distant cousins the baboons, monkeys or even lemurs. However, it could just as easily come from a completely different lineage, such as the cats (remember Red Dwarf?), the weasels, the dolphins or maybe even one of the more intelligent bird groups such as the parrots or the crows. It could even come from some much more unexpected group, for that is the unpredictability of evolution.

The less obvious but more interesting possibility could only occur if we’re talking about a zombie apocalypse caused by a virus or some sort of contagious disease that infects the living rather than raising the dead. If the disease doesn’t completely take over the brain, as was the case of the rage virus in 28 Days Later, some primitive urges or lower brain functions could survive intact. I’m not talking about any intelligent consciousness here but rather the sub-conscious and the innate – those things our bodies do without us having to tell them to do it. While these infected will act like zombies, they could still be stirred by primal urges such as hunger. Once they have munched their way through humanity, these infected will likely turn their attention to other animals in order to feed themselves but these will be both much less numerous and more difficult to catch. Again there will be a mass die-offs, taking with it 95 to 99% of the infected humans but crucially some small fraction will find enough sustenance to survive meaning they won’t die out completely.

Instead, the number of infected will eventually level out as they reach a balance with whichever ecosystem they find themselves in (known to ecologists as the carrying capacity). This will allow some infected persist for years, probably decades, becoming just another predator and/or scavenger which other animals have to deal with. If this happens, another rather interesting question raises its head: will these infected reproduce? If they still retain the primitive urges associated with hunger, it is feasible that they might also retain what might be euphemistically referred to as ‘reproductive’ urges.

So what will happen if an infected becomes pregnant? Well, this will depend on how the disease can be transmitted. If the disease can only be passed from person to person through contact (known as horizontal transmission), whenever an infected gives birth, it’s likely to attack and kill the baby (since the mother will recognise it as an uninfected human and respond accordingly). If this is the case, the infected will eventually die out and the world will carry on without us. If, however, there is vertical transmission, something much more interesting could occur. Vertical transmission means the passing of the disease directly from mother to unborn child. This occurs in many human diseases (think of things like HIV) and would mean that any babies would be born infected and would not automatically be attacked by their mothers. If there’s any of the basic human nurturing instinct left unharmed by the disease, infected mothers might care enough for their children for them to survive into adulthood and a breeding population of infected will come into existence, creating a new lineage of infected humans.

Yet, it might not end there. Given enough time, these new Homo sapiens may eventually evolve some level of immunity to whatever disease it is that’s infecting them and they could eventually regain some of the human qualities not seen since the disease took over the bodies of their distant ancestors. They might even reach the point where they could start to rebuild civilisation. However, the humans will not be the only ones evolving over time; the disease will change too, and the outcome in this evolutionary arms race between the disease and the human immune system will swing first one way and then the other, creating ever-repeating cycles of civilisation and destruction depending on which has the upper hand at any particular point in time. How human societies would cope knowing that at any moment the disease that lies dormant within all of them could re-emerge and destroy everything they have strived to achieve is unclear, but it’s likely this would have highly destabilising effect and it’s unlikely humanity would ever reach it’s current pinnacle of technical development again. This means they’d never reach the point where they could potentially develop a definitive cure.

So what does all this mean? Well, once the humans have gone, the zombies will most likely follow after leaving the Earth to recover and carry on as if we’d never even existed. However, there’s a slight possibility that in the case of zombie-like infected, some will survive, forming a new type of human being that might one day shake off the shackles of the zombie disease, at least temporarily, and re-establish something we might recognise as human civilisation. It’s an interesting thought, isn’t it?

From the author of For Those In Peril On The Sea, a tale of post-apocalyptic survival in a world where zombie-like infected rule the land and all the last few human survivors can do is stay on their boats and try to survive. Now available in print and as a Kindle ebook. Click here or visit www.forthoseinperil.net to find out more. To download a preview of the first three chapters, click here.

To read the Foreword Clarion Review of For Those In Peril On The Sea (where it scored five stars out of five) click here.


6 Responses to “What Will Happen To The Zombies When All The Humans Are Gone?”

  1. Jack Flacco 29/04/2013 at 19:42 #

    You’ve made a number of interesting points, Colin. What I wonder is once the food supply is gone, what happens with the zombies (if the zombies are your classic, non-virulent types). For instance, if the zombies rise up from the dead supernaturally and attack the humans, what will happen if there are no more humans to attack?

    What I think, and this is a personal opinion, the zombies will stay alive until their bodies become a big pile of mush. The earth will give birth again, and on and on this cycle goes.

    Great post!

    • cmdrysdale 29/04/2013 at 20:42 #

      Hi Jack,

      Glad you liked the post. Depending on the exact ‘rules’ behind a zombie apocalypse, I guess there’s other possibilities beyond the ones I considered. I like the idea of there being cycles in zombie uprisings though.

      All the best,


  2. AstralHaggonsBurg 11/01/2014 at 00:22 #

    I get your point of view… One thing that was a problem.. didn’t you mean civilization*? You got the word wrong xD

    • cmdrysdale 11/01/2014 at 10:50 #

      I’m glad you liked this point of view. In terms of getting the word wrong, are you meaning that I used civilisation with an ‘s’ rather than a ‘z’? If so, this is just the British spelling (which I use in all my writing, since I happen to be British!). If not, let me know and I can get it sorted.

      All the best,


  3. Shawn 23/10/2016 at 22:41 #

    My brother started writing a book about this same idea. However, I think he had an interesting twist and idea. He made the leap to evolution in zombies. He made the assumption that over time zombies could evolve as humans did over time. They established conversation then onto rules then onto a government. This government idea was interesting because of the similar rules humans have but twisted to taylor to the zombie culture. in some aspects: what humans would deem against the law the zombies may not.

    as we all think.. just an imaginative theory.

    • Colin M. Drysdale 24/10/2016 at 10:43 #

      Hi Shawn,

      That is an interesting twist.Zombie civilisation, if it were to evolve, it would be an intriguing thing to explore, and particularly what rules they’d have that would differ from ours.

      In many ways it reminds me of the plot of ‘I Am Legend’ (the original book rather than the Will Smith film), although they were vampires rather than zombies. If you haven’t read it, it’s definitely worth checking out (even if you’ve seen the modern film version since this has little in common with the book beyond sharing a title).

      All the best,


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