8 Scientific Theories That Totally Change Zombie Films

7. Fast And Slow Zombies Both Make Scientific Sense

There are generally two types of zombie: Fast and slow.

As anyone with eyes knows, the fast zombies are scarier, but what is the actual difference between the two?

In a book called Do Zombies Dream of Undead Sheep?, written by two neuroscientists with a passion for all things undead, the reason for the difference is down to something they have dubbed the "time-to-resurrection hypothesis."

Essentially, the longer the brain is deprived of oxygen before turning, the slower the zombie will be. Fast zombies typically turn very quickly, sometimes while the host body is still alive, whereas slow zombie tend to emerge sometime after the death of the host. Usually while its companions are gathered around in mourning at perfect bite distance.

This theory really does chime with a lot that we know about brain injury in the real world, so in the event of a zombie apocalypse, take note of how long they're out for.