InThe Walking Dead, the undead Walkers are living cadavers - mindless zombies who live only to eat human flesh, rending innocent people apart with just their teeth and hands. It may seem hard to believe that concept could get any darker, but a revelation from the franchise’s creator will have fans seriously grossed out.

In the recentWalking Dead #111- from Robert Kirkman, Charlie Adlard and Dave McCaig - a fan writes inasking about zombie physiology. Specifically, they want to know what happens after a zombie consumes human flesh. Can the undead digest what they eat, and what happens once they’re full? Kirkman’s answer exposes the gross truth.

Walking Dead Caged Zombie Walker

In response, theWalking Deadcreator writes that in his mind, his zombies are"always pooping,“constantly excreting their human victims. It’s a grim truth of the franchise that eating humans doesn’t even seem to give the Walkers sustenance.See below for Kirkman’s full comments.

The Reveal Has Darker Implications Than It Seems

Zombie biology is a continuous mystery in theWalking Deadcomics. While they seem to continue rotting over time, the undead can somehow move and (to a certain extent) think despite the cessation of biological impulses. One thing they don’t need to do is eat, with Kirkman confirmingthey don’t even digest the parts of human they end up swallowing. The writer states:

I like to think they’re always pooping… undigested bits of flesh… it just passes right through. Fun!

Comic book art: Zombie horde in full color, from The Walking Dead Deluxe

As haunting as it would be to live in a world where the undead stalk you as prey, it’s even darker to imagine the zombie horde constantly relieving itself as it goes, adding a gross edge to the zombie horror. This fact suggests that thezombies aren’t just predatorsbut a potential biological disaster zone, especially in large numbers. While the early comics show small groups of Walkers, later events like the Whisperer War reveal groups that are thousands strong - on that scale,constantly pooping zombies could constitute an environmental disaster, unleashing a wave of bacteria and parasites in their wake.

It’s particularly haunting that Walkers gain no sustenance from eating people and don’t even digest what they snap up. While most predators are part of the food chain, contributing in some way to the cycle of life, zombies exist outside that -they kill without giving, representing death in a way that other antagonists can’t. This fact raises more questions about what is keeping the zombies mobile for so long if they’re not even extracting nutrients from what they consume, but sadly it seems that just has to remain anotherunanswered question about the undead virus.

Zombies as seen in The Walking Dead series finale

Walking Deadhas always been one of the more practical explorations of the end of the world, as the focus on survivors working to create new societies and scrape by in a ruined world asks some very practical questions about the mechanics of survival. However, a few hardcoreWalking Deadobsessives aside, Kirkman’s reveal about the zombie digestive system is probably insight most fans could have done without.

The Walking Dead (2010) Movie Poster