The average true supernatural Zombie will live up to 7 years if it feeds upon human flesh regularly. The paranormal zombie virus that intertwines with human DNA transmutes cells into living dead structures somewhat akin to cancer cells. The zombification virus digests consumed human flesh into metaphysical energy. This is the energy that feeds the virus thereby slowing down the rate of cellular necrosis. If the zombie ingests little or no human flesh then it will completely decay into a skeleton within 3 years or less depending on a variety of environmental factors. Once the brain has sufficiently decayed it will cease moving. Mystical intervention by a practitioner of magic can prolong a zombies life indefinitely. Such zombies act as mindless minions to wreak havoc on behalf of these nefarious witches, warlocks, wizards, dark priests, and sorcerers.
Technically they don’t sleep nor do they need to sleep since they’re dead. However a zombie hoard will stop after a certain amount of time with their heads hanging down while remaining motionless if no prey is present. Zombies that wander off alone will eventually collapse, and appear truly dead if no prey or other zombies are seen after a period of time. However they’ll pop back up again the minute they smell or hear any humans, animals, or zombies. Sometimes weather conditions including a brisk wind will get them animated again. Never assume that a motionless zombie lying on the ground is harmless. Destroy the brain, and ask questions later!
On a related note I’m half zombie, and I only sleep 3-4 hours a night. Clearly that’s all my human half needs despite the average adult requiring 7-8 hours of sleep per night.
Cryptozooglogists, Necrologists, and Zombologists classify zombies as Homo Necrosis Zombifis under the supernatural sciences. The complete paranormal classification is below:
Kingdom: Cryptida (Supernatural Cryptids)
Phylum: Immortalis (Immortals)
Class: SupraNecrosis (Living Dead Beings)
Order: Magica (A Product Of Magic)
Family: Anthropophagis Sanguinus (Survives Off Human Flesh And Blood)
Genus: Homo Necrosis (The Melding Of Human And Zombie)
Species: Homo Necrosis Zombifis (Scientific Name For Zombies)
Cryptida is the seventh Kingdom that mainstream science refuses to acknowledge.
Despite Zombies being technically Immortal they also are in a state of rotting necrosis which means they will be non-animated in less than a decade depending on the circumstances of the environment they menace. However magical intervention could theoretically extend their destructive lives indefinitely. The original supernatural zombie virus is a product of a magical accident. In addition to practitioners of magic raising corpses from the dead the zombies themselves can pass on the virus to make new zombies.