Zombie. The walking dead. Reanimated corpses. The undead.
Whatever you choose to call them, these corpses that rise from the grave to walk the world and terrify — and sometimes infect — its inhabitants are one of the top monsters in popular culture.
The word zombie — originally spelled as zombi — first came into the English language in the 1800s, when poet Robert Southey mentioned it in his History of Brazil.
According to the Merriam-Webster dictionary, the word comes from the Louisiana Creole or Haitian Creole word zonbi, and it is akin to the Kimbundu term nzúmbe, which means ghost.
The word refers to creatures from Haitian folklore that, at its origin, was little more than the ghosts from Western folklore.
However, little by little, the concept evolved to refer to a person that is rendered mindless by a witch doctor, entering a death-like state while still animated, and thus becoming the witch doctor’s slave.
Nowadays, people use the word “zombie” a lot more loosely — often metaphorically — to refer to anyone or anything that presents as apathetic, moves slowly, and demonstrates little awareness of their surroundings.
But do zombies or zombie-like beings actually exist in nature? If so, what are they, and how do they come to enter this state of “undeath?” And can humans ever become zombie-like? In this special feature, we investigate.
1. Zombie ants
Ophiocordyceps is a genus of fungi that has more than 200 species, and mycologists are still counting. Many species of fungi can be dangerous, often because they are toxic to animals, but there is one thing in particular that makes Ophiocordyceps especially frightening.
These species of fungus “target” and infect various insects through their spores. After infection takes place, the parasitic fungus takes control of the insect’s mind, altering its behavior to make the propagation of fungal spores more likely.
Ophiocordyceps “feed” on the insects they attach to, growing into and out of their bodies until the insects die.
One of these species, Ophiocordyceps unilateralis sensu lato, specifically infects, controls, and kills carpenter ants (Camponotus castaneus), native to North America.
When Ophiocordyceps unilateralis infect carpenter ants, they turn them into zombies. The ants become compelled to climb to the top of elevated vegetation, where they remain affixed and die. The high elevation allows the fungus to grow and later spread its spores widely.
Researchers from Pennsylvania State (Penn State) University found that O. unilateralis take full control of the ants’ muscle fibers, forcing them to move as it “wants” them to.
“We found that a high percentage of the cells in a host were fungal cells,” notes David Hughes, who is associate professor of entomology and biology at Penn State.