So AMC has renewed zombie-smashing hit series The Walking Dead for a fifth season, but after five years of shambling around trying to munch the brains of Rick Grimes & co., would there be enough of the zombies left for them to continue walking?

A forensic consultant with Rutgers University-Camden, Kimberlee Sue Moran, thinks the dead would be more threatening to the water table than your brain cavity. “At the root of decomposition is liquefaction,” she said, noting that when the body dies, it immediately begins eating itself from the inside in a process called autolysis.

“Within three days, you would see signs of decomposition, so the body would not be stable enough to run around,” Moran notes. “Rigor mortis is like a body-wide cramp, which would make it hard for the zombie to move… You hear about friendly bacteria and probiotics all the time, and they are friendly until the body dies, then they get a bit hungry.”

The living bacteria from our dead guts continues living after our bodies cease to function, and as a result, the body bloats as the bacteria leaves waste in the form of gas. Those byproducts, and the bacteria themselves, are responsible for pale zombie skin tint.

But what if the brain were reanimated, and those necessary body functions were not stopped, but slowed? “You need the frontal lobe to see and certain parts of the brain to make your arms and legs move, but none of that is possible without oxygen and blood,” Moran says. “The brain is made of cells, so if all the other cells are liquifying, so would the brain.”

“In the movie Resident Evil,” Moran continued, “they said it was a very primitive part of the brain that drives basic instincts like hunger. But sleep and reproduction are also basic instincts and that’s not taking place in any of these stories. Taking in nutrients is not going to serve any purpose for the zombie.”

So what drove Moran’s interests into exploring the plausibility of the zombie? The Danny Boyle bio-thriller 28 Days Later. “28 Days Later caused my irrational fear of zombies because they were biological agent-driven zombies… Part of fear is trying to rationalize what is happening and find ways around it.”

[Image via Gene Page/AMCTV.com]