In Brad Pitt's new movie, "World War Z," a soldier gives Pitt's character the lowdown on their undead opponent: Bullets to the body only slow them down, though head shots kill them. They sometimes ooze a kind of black tarry substance, and they love biting humans "like fat kids love Twix." And as filmgoers watch, they discover that these zombies can hear a Pepsi can drop a mile away, tackle like a Dallas Cowboy in the Super Bowl, are willing to fling themselves off skyscrapers and over giant walls, and are smart enough to use the bodies of their fellow undead as a ladder to clamber toward their human targets.
These are not your grandfather's zombies.
Moviegoers have seen the undead evolve in a thousand gruesome rotting ways since the creatures of 1932's "White Zombie" were docile enough to work in a sugar plantation. George A. Romero took the creature -- which he called a "ghoul," not a "zombie" -- to a whole new level in 1968's classic "Night of the Living Dead," making them totter out of graves to munch on the living. And from then on, Hollywood was off, shambling down a rotting cinematic pathway littered with discarded body parts and ever-evolving zombie lore.
Zombies stayed about as fast as your walker-using Aunt Fannie until the 2002 release of "28 Days Later." Purists will tell you that the infected in that film weren't dead, so are not technically zombies. But no matter, they still introduced the public to the idea of fast movie zombies who no longer staggered after you like a drunk uncle, but match Pittsburgh Steeler Hines Ward (who played a zombie on AMC's "Walking Dead") for speediness.
"I do think that if you had to be bitten by slow movers to turn, you could avoid them and eventually defeat them," said Cal Miller, author of numerous zombie books and zombie comic strip TedDead. " It would be like fighting an army of senior citizens. The fast ones are just horrifying to me. They’ll run you down."
The zombie diet has changed along with their speed. In the Romero film trilogy, zombies would munch on any part of a living human, from scalp to sole. But in 1985's "Return of the Living Dead" -- not a Romero film -- it's said that the zombies specifically consume the brains of the living because only that soothes the pain of being dead. That film explanation led to the popularization of the ever-popular "BRAAAAAINS!" quote so many associate with the living dead.
"Most people's knowledge of the zombie genre seems to be a bit limited," Miller said. "You say 'zombies' and they answer 'brainzzzzz,' But that was pretty much just in the 'Return of the Living Dead' movies/books. You try and explain that zombies eat the whole body and, well, unfamiliar people get either intrigued or grossed out."
Miller finds the brain-eating cliche a bit odd. "Human teeth can't bite through a skull," he said. "Zombies really go for the easy spots. Arms, legs, neck, belly."
Mac Montandon, author of "The Proper Care and Feeding of Zombies," thinks zombies are resourceful when it comes to dining. "In my book, I point out that the zombie diet is not that far off from the Inuits, indigenous peoples of the Arctic region," he said. "I think that, paradoxically, when it comes down to it, zombies have a really clever survival mechanism that kicks in -- meaning if they had to eat, say, someone's elbow to go on not living, they would."
Zombies were once human, and movies differ on whether their intelligence or humanity still exists once they're undead. In 2004, "Shaun of the Dead" played a zombie invasion for laughs, and in 2013's "Warm Bodies," a zombie actually falls in love with a human.
"Zombies are not funny," said Montandon. "But 'Shaun of the Dead' was. In terms of ('Warm Bodies') human-zombie romance, that seems like much less of a stretch than a human-Tom Cruise romance."
Even the way to kill a zombie isn't agreed on by all moviemakers. It's generally agreed that a head injury must be involved, specifically something that destroys the undead brain. Some require zombie bodies to be burned, but in "World War Z," the fingers of a zombie that's been burned almost to solid ash are still shown to wiggle.
"The head can live if cut off at the neck," said Miller. "A personal pet peeve of mine, however, is when a disembodied head groans. No diaphragm, no lungs, no airflow, no groan."
As long as zombie movies continue to make money, the creatures will doubtlessly continue to evolve on film.
"I think zombies are ready for their 'Coneheads' moment," said Montandon, referring to the "Saturday Night Live" aliens who claimed to be French. "That is, they already have so many human characteristics, it's not hard to see them passing as humans in a suburb of Chicago, for instance."
Miller's novel, "Het Madden: A Zombie Perspective," is written from the point of view of an intelligent zombie, and he believes smart zombies will be the next wave.
"I feel there have to be smart and dumb zombies, like smart and dumb people," Miller said. "The smart ones lurk and plan. They don't walk into machetes."