Sorry fellow zombie movies fans but the Zombie Apocalypse as seen in films like Dawn of the Dead just is not credible. Setting aside the issue of dead bodies reanimating, that’s the gimme you have to accept for the setting premise, the hordes of undead overrunning civilization just isn’t going to happen, A friend and I ran these numbers twenty years with much lower level of access to data set and now with the wonders of the internet I can really find data to work with on this subject. My data is pulled from the CDC statistics from 2014 and is applied to the city of Los Angeles.
Way out in the country where did all these bodies come from?
In the USA the rate of death is 823.7 person per 100,000 of population per year. Divide that by 365.25 and you get a daily rate of 2.25 per 100,000 population. L.A. has a population of 4,030,904 giving it an average death rate of 90.69 deaths per day. As you can see we are already seriously deficient in potential zombies. However lets say the anomaly that reanimates the bodies effect all bodies 3 days dead and less. That produces a potential zombie horde of 272.08 units. Now if you simply divided them out by the land area of L.A. (469 square miles) you end up with 1 zombie every 1.72 square miles, but people don’t die even distributed throughout a major metropolitan city. Again taking data from the CDC we can say in rough number that:
37% die while under in patient care (Hospitals)
30 % die at home
19% in long term care or nursing homes
7% at the ER or urgent care.
7% other or unknown.
Of that 3 day total I would spitball – and this is entirely my guess take it as you will – that 90% of those who died at Hospitals, Urgent Cares, Nursing Homes and the like will be bagged, tagged, and either buried or in secure storage. I’m going to be cynical and say only 80% for those who died at home and I’ll be really generous to the future zombie horde and let them have all of the other or unknown. So if we run with those percentages how many free range zombies do we have to threaten the vast population of the City of the Angeles?
52.5 Zombies.
To make matters a little worse… 29.93 of those zombies will be aged 75 or older. Nearly all will start off in buildings already designed and ready for emergencies except the 19.04 that dies in unknown and other locations. In my opinion if you want to have a credible Zombie Apocalypse you need a massive die off in conjunction with the reanimation.
Expoential growth doesn’t get you out of the hole. 1) rememebr that 57% of your zombies are from people ages over 75 years with weak mucles and brittle bones. That population is unlikely to have a 100% hit rate in biting and infecting. 2) those who are bitten do not die at once. They sicken and die, meaning that they die in a facility where security measures can be taken to prevetn the dead from becoming free-range. 3) The exopoential growth argument assume no change in response by authorities. Assume three days before it penetrates the police and others what they are facing. That’s 272 more dead people from just the death rate alone, add in 208 more killed and turned by the initial infection – using the 100% hit rate for our fresh horde- and that’s a grand total of 480 zombies in L.A. That is containable.
Wait. It isn’t the initial die off, it’s the ones they bite who die and reanimate. Even assuming one kill per zombie, you have 52, 104, 208, 416… within 10 iterations you have 53k. It’s exponential growth.
Have you not considered how attractive rotting stinking zombies will be to hungry dogs? And dogs are always hungry. Problem solved.