“First will be the lividity,” said Melissa Unfred, a Texas-based mortician who specializes in natural burials. Lividity is the discoloration process that results from blood sinking and pooling once the heart stops pumping. The part of the body that’s closest to the ground will turn dark red where the blood settles. After about 24 hours, the lower right quadrant of the body will turn a bluish-green color as the bacteria in the pancreas are the first to start digesting tissues in the gut. The skin takes on “a really interesting marbled pattern,” Unfred said “which is actually really pretty, but to each their own.”
Within about 6 hours after death, the eyes and mouth will begin to dry out and pull back a bit. “Right after a body dies, if you’re not embalming, it’s almost impossible to close the eyes or the mouth,” Unfred told Live Science. Embalmers often have to seal the eyes and mouth shut with special tools to make the face look at peace.
Unfred said she thinks the zombies on “Fear the Walking Dead” have eyes and mouths that, for the most part, look like they’ve followed a natural decay process. But the zombies seem to avoid the next step of decomposition: bloat.