Kelly found an article recently that she knew would interest me.
One of the things about zombies that is commonly accepted within the genre is that they are dead and rotting.* And in the normal world, all dead flesh is eventually broken down and picked apart by Mother Nature, leaving only bones, which will also one day disappear. Everything from bacteria to bugs to birds to bears, all feast on whatever carrion they can find. And so one scientist finally asks, how would zombies fare in the real world? Pretty poorly, apparently. As the author puts it:
Relax. Next time you’re lying in bed, unable to fall asleep thanks to the vague anxiety of half-rotten corpses munching on you in the dark, remember this: if there was ever a zombie uprising, wildlife would kick its ass.
*There are notable exceptions. The zombies in films like 28 Days Later and Zombieland, as well as the zombies in the Left4Dead video games, are technically alive, but have been turned into rabid/feral monsters due to some nasty disease.