According to A Sorcerer's Bottle: The Visual Art of Magic in Haiti, "Zombi" is also another name of the Vodou snake god, Damballah. It is akin to the Kikongo word nzambi, which means "god". Damballah is associated with bones and he is known to carry the ancestors on his back to the afterlife.
The term “undead”, a term usually synonymous with “zombie”, actually includes any being that are deceased, yet still behave as if they were alive. This includes ghosts, vampires, zombies, ghouls, mummies, and other creatures. These creatures are usually summoned by a necromancer, a person who uses magic to control the dead.
In the 1980s, a man named Wade Davis, after having studied the subject in Haiti, claimed that a living person could be turned into a zombie by having two toxins injected into the bloodstream. The first being coup de poudre, a neurotoxin found in the flesh of the pufferfish, and the second being dissociative drugs such as datura. The result being a death-like state, allowing the body of the one induced to be controlled by another person.
In American culture, zombies became popular in the 1920s after H.P. Lovecraft wrote the series Herbert West- Reanimator. Though Lovecraft never referred to the creatures as "zombies", it was where the American concept of zombies largely came from.
The film White Zombie, directed by Victor Halperin, made in 1932, is praised as the first legitimate zombie film ever made. This started a whirlwind of zombie films from the 1930s to the 1960s. The 1936 film Things to Come, based on the novel by H.G. Wells, was the first zombie film that involved an apocalyptic scenario. This film features individuals that contract a highly contagious viral disease that leaves them wandering around mindlessly, infecting others on contact.
The 1968 film Night of the Living Dead, directed by George Romero, features the most well-known type of zombie in our culture. These zombies are re-animated by an unknown phenomenon: people that have died of various causes all come back, with little memory of their past lives. While a bite from these zombies is certainly lethal, a bite is not necessary to spread it, because death by any other means would also result in zombification. The only thing they seek is flesh, and they will stop at nothing to get it. They have little intelligence, and wander around the streets in a rigor mortis-like state. They do not attempt to communicate, other than sporadic grunts and screams. The only way to get rid of these zombies is to destroy their brain.
The spin-off films such as Return of the Living Dead, directed by Dan O’Bannon, feature a slightly different type of zombies. These zombies, while also brought back from the dead, are infected with the chemical compound Trioxin. A bite from one of these zombies may or may not result in zombification. These zombies are much more intelligent than Romero zombies, as they retain all their memory from their past lives, but are driven by the uncontrollable desire for brains. Depending on their state of decay when turned into zombies, they can run, jump, swim, and move just like any other human. These zombies can also speak, though most of their speech consists of their desire for brains. These zombies are also much harder to kill, because their entire body must be decimated. Even if one of their limbs is severed, it will stay animated. The only ways to kill these zombies is to either burn them (though this will release the Trioxin into the air, creating a much bigger problem), or electrocuting them until they cease to move.
Newer films such as Resident Evil, 28 Days Later, and I Am Legend, feature zombies that have never actually been dead. These zombies were created by an outbreak in an infection, usually some sort of experiment in a lab that somehow got loose into the general population. These are a form of the type of zombie that Davis suggested. Though these zombies are the type that cause most of the controversy, they do have some historical background to them. Not only this, but they are also the most likely to actually cause the zombie apocalypse.
In conclusion, I would say there are four types of zombies: Necromanced zombies (the dead controlled by the living), Davis zombies (the living infected), Romero zombies (unintelligent dead raised by an unknown cause), and O’Bannon zombies (intelligent dead raised by a chemical substance). The major differences in these four types make it hard to say one is a zombie and one is not. I think the main thing that ties all of them together, the one thing that constitutes being a zombie, is the uncontrollable need for brains.
