But it would take almost four more decades for the modern zombie movie to rise, with the release in 1968 of Night of the Living Dead, the cult classic from director George A. Romero that came to define the genre.

“It set up a lot of the rules as far as having to shoot them in the head and how they crave human flesh,” says Fangoria writer Sean Abley, who adds that the zombies in that film were mostly quiet.

Sound design grew more complex in the two sequels, 1978’s Dawn of the Dead and 1985’s Day of the Dead, where zombies began to emit their now familiar hunger moans. But arguably the most iconic of all zombie sounds — that bellowing cry of “BRAAAAINS!!!” — did not actually appear in a Romero film. The line and its permutations originated in 1985’s The Return of the Living Dead.

Produced by Romero’s former business partner John Russo and directed by Dan O’Bannon, Return diverged sharply from the Romero playbook by adding a heaping dash of black comedy and rock ‘n’ roll to the mix. (A number of notable punk bands from the era, The Cramps and The Damned among them, contributed songs to the soundtrack.)

Return also lays claim to being the first movie in which zombies are capable of forming words at all. In one scene, a female zombie strapped to a morgue slab even speaks full sentences. After being asked why she kills, Fangoria’s Abley says, “[the captured zombie] goes, ‘Braaains!!! We need brains because we’re in so much pain and it makes us feel better!’”

Not much about zombie sounds changed until 2002, when Danny Boyle’s post-apocalyptic chiller 28 Days Later…introduced “fast zombies,” the result of a mysterious “rage virus” that infects much of the planet. The film and its sequels were big hits, and the fast-zombie strain spread in video games like The Last of Us and Call of Duty Black Ops II. 

“They used to just stumble around and moan and groan,” says Peter Brown, a supervising sound editor who helped bring fast zombies to life in the 2006 movie World War Z. “But these zombies were running fast, like guys on a meth binge.”

“We’d tie a piece of meat to a board and we’d let them get close, and they would snap at the meat.”

To achieve that predatory effect, Brown layered animal sounds — jaguars, wild boars, even a whale to give the impression of a zombie horde in the distance — onto vocalizations produced by a group of actors. Many of those sounds come from pre-existing libraries, but on occasion it required going directly to the source.

“We went up to an animal wranglers ranch and they had a couple of wolves on hand,” says Brown, who also oversaw sound for Scouts Guide to the Zombie Apocalypse in 2015. “We’d tie a piece of meat to a board and we’d let them get close, and they would snap at the meat. It makes the human sounds a little more vicious and violent.” But, he adds, “humans are still the best source of zombie sounds.”

That job falls to a dialogue supervisor like Bowles, who typically sends his exhausted actors home after a day of zombie recording with little-to-no voices. For Pride and Prejudice and Zombies, he says, “We would not hire people that had vocal auditions coming up the next day. We put them through the wringer, for sure.”

Voice-over actor Dee Bradley Baker — considered one of the best in the zombie biz — warns that the practice can easily result in permanent damage to your moneymaker. “Try finding ways to not use your vocal cords,” he says. “Use things like your sinuses or parts of your soft palate to modify or mangle your zombie sounds.” Pinching your nose, or inhaling instead of exhaling, can also produce creepy effects without shredding your throat, he says.

When truly in a pinch, sound designers are known to get behind the microphone themselves. Martyn Zub, supervising sound editor on the 2013 zombie romantic comedy Warm Bodies, created most of his own creature sounds.

“I’d sit in a dark room looking at the film with a microphone in my hand and try to bring up all the zombie nature in my body,” says Zub, who believes his background singing in an Australian punk band uniquely prepared him for the gig.

Zub says there were “two types of zombies in Warm Bodies: generic ones that make the regular zombie sound, kind of, ‘Uhhhhggghhh.’ And then there were the Bonies, who were more evil zombies. They sounded like, ‘BLEEEEAGGHAAAAH!’"

“Yeah, it’s really tough on their voices,” says Jerry Ross, who as supervising sound editor for The Walking Dead is widely considered to be Hollywood’s reigning master of zombie soundscapes. Ross says the key lies in finding “the right talent,” and he has worked with the same group of 10 voice actors — referred to in the biz as a “loop group” — since the beginning.

Whenever a new script arrives, the performers scramble to claim any walkers they find particularly memorable. “A lot of it comes down to them wanting to be made into action figures,” says Ross with a chuckle. “The writers get pretty creative: There’s Hanging-Jaw Zombie, Deeply Decaying Zombie. We get to know the special qualities of each — the level of decay or mutations within each of them — before stepping foot in a recording booth.”

Something as simple as gargling water while groaning can be frighteningly effective

To give his zombies a little something extra, Ross turns to an unlikely source: Dave, his business partner’s Dachshund-Jack Russell mix. “When we wrestle with Dave and tickle him a little bit, he goes, ‘GRHAAAAHAHRHAHHAAAA.’ Whenever the zombies feed, we put a little Dave in there for the final piece de resistance.”

And he’s not the only one to turn to man’s best friend for zombie sounds. Brown loves English Bulldogs for their slobbering and labored breathing, and his pet Maltipoo, Poppy, makes “a lot of strange moaning and groaning sounds” that found their way into Scouts Guide.

The tricks of the trade are seemingly endless. To achieve the sound of the White Walkers in Game of Thrones (yup, those are zombies, too) Brown recorded his children “screaming in a hot tub during a windstorm.” He adds, “The bubbling gave it an eerie ambience.” Something as simple as gargling water while groaning can be frighteningly effective, and the silver lining to any nasty cold is that you can record the snotty sounds and bequeath them to a zombie at a later date.

Technology then adds the finishing touch, through layering, pitching up or down, or running the sounds through any number of zombie-esque filters like iZotope Nectar or the aptly named Krotos Dehumaniser.

“You want to use everything: your family, your sick self, pro actors, animal recordings, post-processing tools, and editing to screw the sound up as much as possible — without letting it get unhinged from the screen,” Brown says. “Bottom line, those zombies need to be believable.”