A couple years ago I was alone in my house when I heard my sliding door open. I asked " Is anyone there" but noone answered. I suddenly heard my dog start barking uncontrollably. I walked to the other end of the house where my sliding door was. my dog was just going crazy. She normally runs out the door when given the chance but she looked like she was scared shitless to go out the door. I hurried and closed the door. My dog was still barking as she watched the same spot outside where i couldnt see anything. Is it true that dogs can see the paranormal?

My dog could see things that I couldn't see.  
I had gotten a new Australian cd.  I was playing it when a particularly powerful digeridoo part was playing, He started growling, looking out the window, came and stood guard in front of me, growling at the window.

He also helped me with doing energy work with clients.  He would move from place to place next to their bodies to help them move energy while I bowled them. He was very good at it.

Dogs and cats are very aware of energy spots, disembodied entities.

My partner's cat was in the hospital for a week.  When she got back she started walking thru the house, she would get to a place in a room and start meowing, for long periods of time, looking at a place in the room.  She went thru the  entire house and went to specific places.  I watched her as she did this.  My partner was concerned.  I kept saying she was telling her friends all about her experience.  Pretty soon she stopped and went to sleep.
As I watched her later, over the months.  She often went to these same places and would have little conversations with whatever it is that was there.

I had a dog that did a similar thing once. Years ago I went for a walk on a sunday evening and when i came back to my house the dog started to bark, but he wasn't barking at me, he was barking at something that apparently was behind me. it was as if i had come with a friend or someone that the dog didn't know. I came into my house and the dog didn't follow me as usual, instead he stayed there staring at some spot. i looked through the windown a few times and the dog didn't move, he kept barking steady at the fence and he looked scary too. it was so damn creepy because nobody was there.

as tourbi said, cats are aware of energy and spirits too. I used to have a cat that would do all sort of weird things and movements at times. she would sometimes stare at spots and make it so obvious that she could perceive stuff that i couldn't.

oh my god she is so precious!(the dog) and thanks guys for the insight.