Could Zombies Exist? Exploring the Science Behind Them

The human zombies of fiction fortunately (or unfortunately for some) do not exist. This may come as a disappointment to zombie fans, but there are many scientific reasons why the zombie-like condition popularized in books and film would be impossible for humans. However, other forms of zombies exist in folklore and even in nature. We chatted with a horror expert to help us delve into the origins of zombies, why zombies can’t biologically exist, zombies in the natural world, and more.

Do zombies exist?

Horror expert Sydney Bermudez says it’s impossible for people to turn into the zombies we see in movies and on TV. However, zombie-like figures exist in Haitian folklore. Also, certain parasites in nature and diseases, like rabies, can cause zombie-like behaviors and symptoms in the infected.

Section 1 of 7:

Are zombies real?

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No, the zombies presented in fiction don’t exist in reality. There are many factors that would make it biologically impossible for a human to turn into a zombie in the first place. As an undead being, a real zombie would lack the metabolism, energy, and physical ability to function in order to survive. However, there are zombie-like conditions present in nature, such as parasites that can take over and control their host’s movements.
- “While the fictional zombies we see in movies aren’t possible based on what we currently know, there are real parasites, viruses, and neurological conditions that can dramatically alter behavior,” explains Bermudez. “For example, the rabies virus can cause aggression, and the fungus Ophiocordyceps is known for controlling the behavior of insects like ants.”^{[1]
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- “These real-world examples are often cited as inspiration for modern zombie fiction, but there’s no evidence that humans could become ‘movie-style’ zombies,” Bermudez adds.^{[2]
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Meet the wikiHow Expert

Sydney Bermudez is an urban legends and Mexican folklore expert and horror content creator. She uses social media to explore how horror intersects with pop culture, social media, and modern myths.

Section 2 of 7:

What is a zombie?

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This is the most well-recognized archetype of a zombie that’s portrayed in pop culture. Zombies are basically corpses that become reanimated through different means. In a lot of science fiction, this happens through some sort of radiation, bacteria, or virus. In all cases, zombies are out to feast on people, so coming into contact with one is deadly.^{[3]
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Why Zombies Scientifically Can’t Exist

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While things like resuscitation and people awakening from comas do happen, there isn’t a way to bring back the dead. Some current studies have been able to restore function to cells in organs in pigs that have been dead for an hour. However, there’s been no progress in being able to resurrect a person who's died. Plus, there have been no cases of a human returning as a zombie after death.^{[4]
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Cleveland Clinic
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Viruses can’t dramatically alter your genetic code. Unlike the zombie virus outbreak presented in Resident Evil, genetic mutations caused by viruses are much more subtle in real life. In fact, viruses that alter your genetic code have been part of human existence for millions of years. And, these viruses are treatable with options like vaccines and antivirals. This means there’s no way a virus could go haywire and infect your DNA with a zombie condition.^{[5]
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Cleveland Clinic
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- Researchers also confirm that no virus currently exists that causes zombie-like symptoms.^{[6]
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Blood transfers oxygen between cells so the body can function. However, the reanimated corpse of a zombie doesn’t have blood and, therefore, no energy source. There’s no way a zombie could move or have the cognitive ability to do anything without blood.^{[7]
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In shows like The Walking Dead, zombies sure can take a beating and still survive. Well, in reality, zombies wouldn’t be that invincible. The body can’t endure harsh circumstances for long, such as physical trauma or extreme temperatures. It would be biologically impossible for a zombie to be hurt badly and not be weakened and succumb to their wounds.^{[8]
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In zombie movies like 28 Days Later, the zombie condition is highly contagious and spreads like wildfire. In that film, for instance, if you get a drop of blood in your eye, you’re a zombie! However, so many things would have to line up for that to even happen in the first place. Healthcare facilities today are also equipped to administer immediate treatment to prevent medical emergencies from worsening.^{[9]
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Cleveland Clinic
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Section 4 of 7:

“Zombies” in Nature

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Ophiocordyceps fungi, or cordyceps, is the fungal infection that starts the zombie apocalypse in the TV series, The Last of Us. In real life, it’s actually a parasitic fungus that can’t infect humans but does infect certain insects, like carpenter ants. The fungi infect an ant with chemicals in order to control it. These chemicals cause the ant to climb plants while still alive. The ant eventually dies once it’s reached higher ground, and a mushroom sprouts out of its corpse to spread more spores and infect more ants.^{[10]
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Rabies is a viral disease that can infect animals and humans and is spread through bites or scratches. It’s a condition that attacks the nervous system and creates aggressive and unusual behavior in the infected, such as violence, confusion, and loss of consciousness. While rabies can be fatal in humans, it can be treated with urgent medical attention.^{[11]
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Centers for Disease Control and Prevention
Main public health institute for the US, run by the Dept. of Health and Human Services

Go to source} Rabies may have inspired a lot of zombie fiction, but it’s not a zombie disease.
Prion diseases happen when proteins in the body misfold, leading to brain damage and death. There are different types of prion diseases, but they all generally result in neurological symptoms, like tremors, difficulty moving, and personality changes. These effects can seem zombie-like. Prion diseases are very rare. They’re usually transmitted if you eat or handle meat contaminated with prions or are exposed to contaminated medical equipment during surgery.^{[12]
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Centers for Disease Control and Prevention
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Toxoplasma gondii is a parasite that’s believed to be carried by about a third of people. It causes an infection called toxoplasmosis. Some research suggests toxoplasmosis may cause behavioral changes in humans, but it’s not conclusive. However, the infection has a much stronger impact on animals, like mice and rats. Infected mice and rats lose their fear of cats, making them more vulnerable to being eaten.^{[13]
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There are parasitic wasps that can infect different insects and hijack their motor control so they can reproduce. Parasitic wasps are known to target caterpillars, cockroaches, and spiders to use as hosts. They lay their eggs inside these insects. Once the eggs hatch, the larvae feed on the host, eventually killing it.^{[14]
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There are worms that live in crickets temporarily and can manipulate their behavior. They’re able to control their host by releasing certain chemicals that attack the cricket’s nervous system. For example, the worm can direct the cricket to jump into water so it can emerge to lay its eggs.^{[15]
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Section 5 of 7:

Is a zombie apocalypse possible?

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A zombie apocalypse can’t happen. The way fiction has portrayed this kind of catastrophe isn’t possible because dead bodies don’t come back to life and there isn’t a virus that suddenly turns humans into cannibalistic monsters. However, zombie scenarios have been used by some researchers to help them figure out how to improve emergency preparedness in the event of sudden outbreaks.^{[16]
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- The CDC published an article titled Preparedness 101: Zombie Pandemic as an engaging way to educate the public on how to prepare for emergencies.^{[17]
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- The scenario of an imaginary zombie outbreak has also been used by educational institutions as a way to answer questions about what to do in a real-life crisis.^{[18]
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- Find out how well you’d do in a zombie outbreak by taking our Zombie Apocalypse quiz!

Section 6 of 7:

Origins of Zombies

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Zombies are rooted in Haitian folklore. “The concept of zombies traces back to Haitian folklore and Vodou traditions, where a zombie was believed to be a person revived or controlled through supernatural means,” says Bermudez.^{[19]
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Sydney Bermudez
Horror Expert

Expert Interview} According to Haitian legends, humans who commit crimes, such as rape or land theft, receive a spiritual punishment called zombification.
- During zombification, it’s said that the person buried alive and brought back to life through necromancy by a bokor, a voodoo sorcerer or witch. The zombie serves the bokor and is under their control.^{[20]
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- It’s believed the early development of the zombie figure was a reflection of Haitian slavery and the slaves’ experiences with their slave owners.
- William Seabrook’s 1929 book The Magic Island brought widespread attention to Haitian zombie folklore.
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“Zombie” derives from the Kongo words nzambi (“god”) and zumbi (“fetish”). The terms are associated with Kongo deities, like the creator deity Nzambi Mpungu and the serpent deity Li Grand Zombi, and are general words for a divine spirit. According to Central African beliefs, deities classified under these umbrella terms are Nkisi spirits or bodiless spirits that inhabit objects.^{[21]
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- South Africa has legends of creatures called “xidachane” and “maduxwane.” Stories vary by community, but it’s believed a dead person can be zombified by a small child or witch and enslaved.^{[22]
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Section 7 of 7:

Zombies in Pop Culture

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Zombie movies and TV series have sparked a zombie obsession. Many films and TV shows have been a major catalyst for people’s fascination with these undead creatures. Some of the most popular and influential zombie movies and series include White Zombie, Night of the Living Dead, Resident Evil, and The Walking Dead.
- “The modern flesh-eating zombie largely comes from films,” says Bermudez, “especially George A. Romero’s Night of the Living Dead (1968), which completely reshaped the zombie into the version most people recognize today.”^{[23]
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While the monster in Mary Shelley’s novel Frankenstein isn’t called a zombie, many people feel the creature that’s brought to life in the story influenced the development of the zombie figure. Fiction that does feature zombies includes works like World War Z, Pride and Prejudice and Zombies, and the anthology Book of the Dead.