How A Zombie Outbreak Might Actually Happen — and How to Protect Yourself

Of all the fictional ways humanity might possibly kill itself, zombies are the most likely. Here's the data to prove it.

How A Zombie Outbreak Might Actually Happen — and How to Protect Yourself
Welcome to 'Zedtown' -- an adventure event where competitors play out a zombie apocalypse: people race to reach an evacuation point to ensure their survival, but must also avoid being caught and turned by the 'undead'. Credit: PETER PARKS/AFP/Getty Images

If any of our fictional monsters are going to kill us, it's zombies. Why? Because the vast majority of zombie scenarios have two things in common -- a pandemic, and the extinction of humanity. And both of those scenarios are scientifically plausible.

Pandemics, or global disease outbreaks, don't need zombies to be terrifying: they're the third most likely cause of an extinction event according to the Global Catastrophic Risk Report (GCRR), as we've told you before. “Between the Spanish Flu, the Black Death, and the Great Plague of Justinian, over 25% of the world's population was killed by disease," according to the GCRR. Pandemics have such high death counts because they emerge from viruses we haven't built up an immunity to -- namely, ones that come from animals. “Viruses that have caused past pandemics typically originated from animal influenza viruses," reports the World Health Organization (WHO).

A zombie pandemic would be quite a bit worse. Partly because zombies could be created the same way, like in the film 28 Later. But also because the result of a zombie pandemic isn't infection: it's consumption. Remember: the goal of almost every single zombie is to eat humans, be it their flesh, organs, or braaaaaaaaains.

Credit: The Walking Dead / AMC

That cannibalistic bent complicates our usual protocol for handling pandemics. The three major steps to handling a normal pandemic are prediction, modeling and treatment, reports Popular Science. The usual protocol is for scientists to “track and collect zoonotic [infectious animal] pathogens in 20 hot-spot countries in order to create a database of the most dangerous." Once they've identified a potential threat, they use “various data, including insect populations, human demographics, and airline routes, to map outbreaks. Health agencies use the maps to plan a response," which can be rapid vaccination or quarantine, depending on the spread and speed of the disease.

If the pathogen causes people to eat each other, it breaks down that entire protocol: rapid vaccination and quarantine are necessary almost immediately because the disease spreads more quickly, giving scientists less time to accurately model and track the disease -- much less create a vaccine.

How quickly would a zombie pandemic spread? There are 6 different possibilities, according to João V. Tomotani from the University of Sao Paolo, Brazil. He crunched all sorts of numbers for Geek Studies, from the number of humans in a given area and the minimal number of zombies needed to infect them, to the amount of time needed to train the humans in survival skills and the time needed to develop and distribute a vaccine. Those are a lot of variables to handle, and he punched them all into a simple turn-based game to create each model. He found that “in no scenario zombies stayed inactive for long, being either reanimated, destroyed or cured very quickly." Meaning, a zombie pandemic will always spread relatively quickly -- as long as there are living people to contaminate. Or, as Tomotani bleakly summarizes, “all humans have a chance of becoming a zombie."

Here's our best-case scenario:

Credit: Geek Studies

In this scenario, 20% of the population were trained after the first infection, and that took 500 turns. After 2,000 turns, 30% of the population had a vaccine. From there, everything goes slowly downhill and humans go extinct at 20,000 turns. “After the zombies “invaded" the human colony, the infection began to spread quickly," Tomotani explains. “Once the population was trained and armed, the rate of infection got slower and the rate of zombie destruction got higher. Once the population was equipped with vaccines, the number of susceptible humans slowly rose for a while. Humanity's demise was that the zombie infestation had already gotten out of control, with way too many zombies."

Again, that's our best-case scenario. Here's our worst:

Credit: Geek Studies

This is what happens when it takes too long to arm a population, as Tomotani writes: “Once the population was trained and armed, the number of zombies was already overwhelming and there was nothing to be done. Humans became extinct after close to 1,000 turns and more than 7,500 zombies were left at the end."

That, my friends, is the end of humanity.

But don't worry! There are ways to survive a zombie apocalypse. The best way is to get ahead of the outbreak and move somewhere with a small enough population where you can avoid it. You'll also need to be near fresh water and in a temperate enough climate to grow your own food, since supermarkets and Seamless will most likely be down. YouTuber Matthew Patrick (MatPat) looked at pandemic models, global population trends, and agricultural calendars to figure out the best place to go: a tiny little town near Ontario, Canada.

Credit: The Game Theorists/YouTube

MatPat won't tell us the second most popular place to go, but looking at the data it's safe to assume it's also in Canada as it would have to be in the same latitude and climate. Plus, MatPat is a stickler for using real science to solve fictitious problems; he even figured out the best weapon to use against zombies. I trust him.

If you don't feel like traveling to Canada, or your passport gets eaten by the walking dead, don't worry: some states are surprisingly well-prepared to ride out a zombie apocalypse. You just need to get to them before the outbreak starts:

Credit: Estately

Estately is more light-hearted in their approach than either Tomotani or MatPat. They use different data points (largely drawn from Facebook interests) and are not at all rigorous in their modeling. They don't even specify the speed or kind of zombie outbreak they're accounting for. Still, their chart does have similar useful factors for surviving a zombie apocalypse. The biggest indicator of human success from Tomotani's models, remember, is quicky training and arming the surviving human population. Military personnel and veterans are the two most important factors in Estately's rankings, and they are most likely to train and arm a human population for their survival.

Other important takeaways from Estately's graph include states with physically active populations and fewer obese people are more likely to arm themselves and fight for survival. Those factors far outweighed a state's success than how many people had guns and liked shooting them (including activities like “laser tag" and “paintball"). However, states with high concentrations of people who play zombie video games had a tactical advantage as well because they understood the enemy. States like Massachusetts and Connecticut ranked so low not because they weren't fit, but because few people watch The Walking Dead or play Resident Evil. TL; DR -- put down the Halloween candy and stay the heck away from the East Coast.

Credit: Estately

And now you know how to survive the zombie apocalypse. Good luck!

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7 most notorious and excessive Roman Emperors

These Roman Emperors were infamous for their debauchery and cruelty.

Nero's Torches. A group of early Christian martyrs about to be burned alive during the reign of emperor Nero in 64 AD.

1876. Painted by Henryk Siemiradzki.
Politics & Current Affairs
  • Roman Emperors were known for their excesses and violent behavior.
  • From Caligula to Elagabalus, the emperors exercised total power in the service of their often-strange desires.
  • Most of these emperors met violent ends themselves.

We rightfully complain about many of our politicians and leaders today, but historically speaking, humanity has seen much worse. Arguably no set of rulers has been as debauched, ingenious in their cruelty, and prone to excess as the Roman Emperors.

While this list is certainly not exhaustive, here are seven Roman rulers who were perhaps the worst of the worst in what was one of the largest empires that ever existed, lasting for over a thousand years.

1. Caligula

Officially known as Gaius (Gaius Caesar Augustus Germanicus), Caligula was the third Roman Emperor, ruling from 37 to 41 AD. He acquired the nickname "Caligula" (meaning "little [soldier's] boot") from his father's soldiers during a campaign.

While recognized for some positive measures in the early days of his rule, he became famous throughout the ages as an absolutely insane emperor, who killed anyone when it pleased him, spent exorbitantly, was obsessed with perverse sex, and proclaimed himself to be a living god.

Caligula gives his horse Incitatus a drink during a banquet. Credit: An engraving by Persichini from a drawing by Pinelli, from "The History of the Roman Emperors" from Augustus to Constantine, by Jean Baptiste Louis Crevier. 1836.

Among his litany of misdeeds, according to the accounts of Caligula's contemporaries Philo of Alexandria and Seneca the Younger, he slept with whomever he wanted, brazenly taking other men's wives (even on their wedding nights) and publicly talking about it.

He also had an insatiable blood thirst, killing for mere amusement. Once, as reports historian Suetonius, when the bridge across the sea at Puteoli was being blessed, he had a number of spectators who were there to inspect it thrown off into the water. When some tried to cling to the ships' rudders, Caligula had them dislodged with hooks and oars so they would drown. On another occasion, he got so bored that he had his guards throw a whole section of the audience into the arena during the intermission so they would be eaten by wild beasts. He also allegedly executed two consuls who forgot his birthday.

Suetonius relayed further atrocities of the mad emperor's character, writing that Caligula "frequently had trials by torture held in his presence while he was eating or otherwise enjoying himself; and kept an expert headsman in readiness to decapitate the prisoners brought in from gaol." One particular form of torture associated with Caligula involved having people sawed in half.

He caused mass starvation and purposefully wasted money and resources, like making his troops stage fake battles just for theater. If that wasn't enough, he turned his palace into a brothel and was accused of incest with his sisters, Agrippina the Younger, Drusilla, and Livilla, whom he also prostituted to other men. Perhaps most famously, he was planning to appoint his favorite horse Incitatus a consul and went as far as making the horse into a priest.

In early 41 AD, Caligula was assassinated by a conspiracy of Praetorian Guard officers, senators, and other members of the court.

2. Nero

Fully named Nero Claudius Caesar, Nero ruled from 54 to 68 AD and was arguably an even worse madman than his uncle Caligula. He had his step-brother Britannicus killed, his wife Octavia executed, and his mother Agrippina stabbed and murdered. He personally kicked to death his lover Poppeaea while she was pregnant with his child — a horrific action the Roman historian Tacitus depicted as "a casual outburst of rage."

He spent exorbitantly and built a 100-foot-tall bronze statue of himself called the Colossus Neronis.

He is also remembered for being strangely obsessed with music. He sang and played the lyre, although it's not likely he really fiddled as Rome burned in what is a popular myth about this crazed tyrant. As misplaced retribution for the fire which burned down a sizable portion of Rome in the year 64, he executed scores of early Christians, some of them outfitted in animal skins and brutalized by dogs, with others burned at the stake.

He died by suicide.

Roman Emperor Nero in the burning ruins of Rome. July 64 AD.Credit: From an original painting by S.J. Ferris. (Photo by Kean Collection / Getty Images)

3. Commodus

Like some of his counterparts, Commodus (a.k.a. Lucius Aelius Aurelius Commodus) thought he was a god — in his case, a reincarnation of the Greek demigod Hercules. Ruling from 176 to 192 AD, he was also known for his debauched ways and strange stunts that seemed designed to affirm his divine status. Numerous statues around the empire showed him as Hercules, a warrior who fought both men and beasts. He fought hundreds of exotic animals in an arena like a gladiator, confusing and terrifying his subjects. Once, he killed 100 lions in a single day.

Emperor Commodus (Joaquin Phoenix) questions the loyalty of his sister Lucilla (Connie Nielsen) In Dreamworks Pictures' and Universal Pictures' Oscar-winning drama "Gladiator," directed by Ridley Scott.Credit: Photo By Getty Images

The burning desire to kill living creatures as a gladiator for the New Year's Day celebrations in 193 AD brought about his demise. After Commodus shot hundreds of animals with arrows and javelins every morning as part of the Plebeian Games leading up to New Year's, his fitness coach (aptly named Narcissus), choked the emperor to death in his bath.

4. Elagabalus

Officially named Marcus Aurelius Antoninus II, Elagabalus's nickname comes from his priesthood in the cult of the Syrian god Elagabal. Ruling as emperor from 218 to 222 AD, he was so devoted to the cult, which he tried to spread in Rome, that he had himself circumcised to prove his dedication. He further offended the religious sensitivities of his compatriots by essentially replacing the main Roman god Jupiter with Elagabal as the chief deity. In another nod to his convictions, he installed on Palatine Hill a cone-like fetish made of black stone as a symbol of the Syrian sun god Sol Invictus Elagabalus.

His sexual proclivities were also not well received at the time. He was likely transgender (wearing makeup and wigs), had five marriages, and was quite open about his male lovers. According to the Roman historian (and the emperor's contemporary) Cassius Dio, Elagabalus prostituted himself in brothels and taverns and was one of the first historical figures on record to be looking for sex reassignment surgery.

He was eventually murdered in 222 in an assassination plot engineered by his own grandmother Julia Maesa.

5. Vitellius

Emperor for just eight months, from April 19th to December 20th of the year 69 AD, Vitellius made some key administrative contributions to the empire but is ultimately remembered as a cruel glutton. He was described by Suetonius as overly fond of eating and drinking, to the point where he would eat at banquets four times a day while sending out the Roman navy to get him rare foods. He also had little social grace, inviting himself over to the houses of different noblemen to eat at their banquets, too.

Vitellius dragged through the streets of Rome.Credit: Georges Rochegrosse. 1883.

He was also quite vicious and reportedly either had his own mother starved to death or approved a poison with which she committed suicide.

Vitellius was ultimately murdered in brutal fashion by supporters of the rival emperor Vespasian, who dragged him through Rome's streets, then likely beheaded him and threw his body into the Tiber river. "Yet I was once your emperor," were supposedly his last words, wrote historian Cassius Dio.

6. Caracalla

Marcus Aurelius Antoninus I ruled Rome from 211 to 217 AD on his own (while previously co-ruling with his father Septimius Severus from 198). "Caracalla"' was his nickname, referencing a hooded coat from Gaul that he brought into Roman fashion.

He started off his rise to individual power by murdering his younger brother Geta, who was named co-heir by their father. Caracalla's bloodthirsty tyranny didn't stop there. He wiped out Geta's supporters and was known to execute any opponents to his or Roman rule. For instance, he slaughtered up to 20,000 citizens of Alexandria after a local theatrical satire dared to mock him.

Geta Dying in His Mother's Arms.Credit: Jacques Pajou (1766-1828)

One of the positive outcomes of his rule was the Edict of Caracalla, which gave Roman citizenship to all free men in the empire. He was also known for building gigantic baths.

Like others on this list, Caracalla met a brutal end, being assassinated by army officers, including the Praetorian prefect Opellius Macrinus, who installed himself as the next emperor.

7. Tiberius

As the second emperor, Tiberius (ruling from 42 BC to 16 AD) is known for a number of accomplishments, especially his military exploits. He was one of the Roman Empire's most successful generals, conquering Pannonia, Dalmatia, Raetia, and parts of Germania.

He was also remembered by his contemporaries as a rather sullen, perverse, and angry man. In the chapter on his life from The Lives of the Twelve Caesars by the historian Suetonius, Tiberius is said to have been disliked from an early age for his personality by even his family. Suetonius wrote that his mother Antonia often called him "an abortion of a man, that had been only begun, but never finished, by nature."

"Orgy of the Times of Tiberius on Capri".Painting by Henryk Siemiradzki. 1881.

Suetonius also paints a damning picture of Tiberius after he retreated from public life to the island of Capri. His years on the island would put Jeffrey Epstein to shame. A horrendous pedophile, Tiberius had a reputation for "depravities that one can hardly bear to tell or be told, let alone believe," Suetonius wrote, describing how "in Capri's woods and groves he arranged a number of nooks of venery where boys and girls got up as Pans and nymphs solicited outside bowers and grottoes: people openly called this 'the old goat's garden,' punning on the island's name."

There's much, much more — far too salacious and, frankly, disgusting to repeat here. For the intrepid or morbidly curious reader, here's a link for more information.

After he died, Tiberius was fittingly succeeded in emperorship by his grandnephew and adopted grandson Caligula.

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