Why is my dog absolutely terrified of the dark?

When I mean my dog is scared of the dark, I mean she's absolutely terrified. The door could be wide open but when the lights are off in a room where she's left alone, I hear her crying- just to turn on the lights to see her eyes bigger than I've ever seen them and shaking. I am quite concerned but at the same time can't help but laugh. She literally won't move until the lights are on. Humans have strange fears as it is... guess dogs have phobia's too?
Here's my cute little coward:
Why is my dog absolutely terrified of the dark?
Why is my dog absolutely terrified of the dark?
Post Opinion