Reasons Werewolves don’t exist: Contrary to the belif that Native Americans have that a man can change into an animal, people cannot turn into animals, it’s just not humanly possible. Therefore there’s no way possible for a man to turn into a rabid wolf and start going around killing people. Also the moon has no effect on how people act despite what some may say.
Reasons they could exist: Like a suggested in the vampires part again we go back to the evolution chart. In a way early pre-humans were more animal like so in a way a werewolf was more possible. Also there could be a genetic effect in man to which he grow a tremendous amount of hair, so much that he looks like a werewolf. Yes this seems ridiculous but again these are just two theories as to how werewolves could exist.
Do Zombies Exist?
Reasons Zombies exist: Well first off Zombies do exist just not in the way we think they do. Zombies are real and it’s a practice in Africa and of voodoo in which a person is controlled and sometimes even buried to believe they are dead. For a more thorough and better analysis check out a piece called Voodoo Zombies vs Flesh eating Zombies on https://monstersofmidian.wordpress.com/2016/10/15/31-days-of-halloween-day-13-voodoo-zombies-vs-flesh-eating-zombies/" target="_blank" rel="nofollow">Monsters of Midian’s website. She gives a great breakdown of the difference and how real one is from the other.
Reasons Zombies don’t exist: If you read the link I sent you then you’ll know why and what kind of zombies exist. So the bigger question is do the zombies we perceive in movies and television exist? Yes and no. The truth is they exist except they aren’t called zombies, they’re simply called “cannibals”. People who eat flesh are not zombies they are just cannibals and either psychopaths or people from an ancient tribe in other countries who believe in eating other humans. “Zombie” has no relevance to flesh eaters in the real world but somewhere down the road perhaps George Romero himself decided to create a new type of zombie who is dead and eat’s flesh and brains. The only way such a zombie could exist is if the voodoo sorcerer who made the zombie told him to eat human flesh and brains so by that standard...they could exist although I don’t think they believe in doing that.