The rise of zombie hordes like in The Walking Dead series would wipe out all but 181 people in just 100 days, a study made by the University of Leicester shows.
The University of Leicester undergraduates used zombies as a model for a potential deadly disease that spreads over time.
Are zombies the next evolutionary step of the human species?
In their analysis, the researchers assumed that each zombie would have a 90 percent success rate in infecting a person each day.
That would mean that the disease would be twice as contagious as the Black Death that devastated Europe in the 1300s.
In their analysis, the researchers assumed that a zombie could stay alive for 20 days without eating.
At a population of 7.5 billion people, starting with just one zombie it would take 20 days for an epidemic to occur. Not taking into account geographical barriers, it would take 100 days to leave only 181 humans alive.
Hope for mankind
Taking geographical isolation into account (zombies do not leave their current region until there are 100,000 flocked into a hoard), human survivors would number 273 by day 100.
If humans are able to kill zombies, the situation gets better. In a follow-up analysis, each human got a 10 percent chance of killing a zombie each day.
It also accounted for human reproduction, assuming reproductive-age women would be able to have a baby every three years.
Under this model, the human population rapidly dropped off to the order of hundreds again, but assured that zombies would die off after 1.000 days.
With less than 1,000 humans left on Earth, it would take 27 years for the human population to start growing again.
Other studies have shown that it would take just 160 people, with equal proportion between males and females, to keep the species alive in the absence of inbreeding.