Zombie hordes feature prominently in Surviving The Evacuation. I never
intended this to happen, but the more I wrote, the more logical their inclusion
was. The undead are attracted to noise. In a dead world, with no machines, few
animals, and fewer people, the loudest sound would be that of the living dead.
They would gravitate towards one another. One or two, or one or two hundred,
might become trapped behind some drystone wall out in the wilds of Lancashire. Their
numbers would grow until even that rigid barrier broke. Thousands would drift
across the countryside. As they did, shoes and feet would kick at stone,
chipping away at sole and skin as much as they wore down masonry, but
eventually the wall would be ground to dust. All it would take is time. And
over time, that thousand zombies would meet another thousand, and another, and
another, and more still until, with their trampling feet louder than a storm,
they slouched through the countryside, turning all to mud and ruin.
But how big would a horde get? Well, it may help if you imagine
yourself as a zombie. Wherever you are right now, at home, at work, out in the
street (especially if you are out in the street), pretend to be one of the
living dead. Stagger a bit, paw at the air, snap your teeth. And as you are
doing that, notice how your arms are waving around. Notice how far you are
moving. (It might help if you affix some kind of powder to the soles of your
shoes. If you are at work, why not try toner from a copier.) Now keep going,
staggering back and forth. Go on. I’ll tell you when to stop.
No, not yet.
Keep going. Keep those arms waving and pawing, those feet
stumbling and tripping, almost but not quite, about to fall. A little longer -
well, actually a lot longer. Keep it going for another hour or so (thinking
about it, this could be the next get-fit craze. Zombi-cise. I must remember to
trademark that). Okay, so stop pretending to be a zombie (and apologise to
any passers-by or co-workers you have hopefully terrified) and let’s imagine
there are two of zombie-you. If your left arm collides with the other creature,
and remembering that you are devoid of all thought and reason, you’ll knock
this other creature to the left or yourself to the right, in line with the
Newton’s Third Law of Motion. And thus is the direction the horde travels
decided.
Most of the horde can only see the decaying back of the
creatures in front. They can only hear the deafeningly loud, irregular stamp of
necrotic feet, but they think that there is prey ahead. They are a great
undulating mass of death, with about... check the area on the ground now
covered in toner. It’s an irregular circle with a diameter of about 12 feet,
right? (This is the average I got in my many, many experiments.)
When there is no prey, the undead squat or stand motionless.
But remember that the horde isn’t stationary, they act in pursuit of this
unseen prey. The laws of physics tell us* that they will form a great
undulating, pulsating mass of death, pushing and shoving at one another as they
heedlessly slouch across the countryside.
An irregular circle of 12 feet in diameter is approximately
452 square feet. Of course, as we’ve stated, this is an irregular circle for
one of the creatures. The area that they occupy will overlap with their
neighbours, so this is only giving us a rough estimate. Caveat over. How big is
the horde?
There are 27,878,400 square feet in a square mile. Dividing that
by 452 gives us 61,677. 87. Now, technically speaking you can have a fraction
of a zombie, depending on how much of its body has been crushed, battered, or
broken. For the purposes of this exercise, let’s round it up to an even number.
61,678 zombies per square mile. That’s the best-case scenario, and assumes the undead are
all being respectful of one another’s personal space. The sad reality is that
it is likely to be closer to twice that number. And that’s just in one square
mile.
* For the record, the above is why I don’t teach physics or
maths.