Some people explain that when dogs bark
at empty yards and
blank walls it is just normal canine behavior. They point out
that dogs see things we are not attuned to. They point out
that there is nothing paranormal about the behavior; dogs
have a much better sense of hearing than we do and notice a
lot more than we are able to. Some others just think they are
afraid of the dark.
But do they see spirits? Are they barking at ghosts? 
Are dogs
able to sense the residual energy left by former inhabitants? It
is already known that dogs can sense cancer and detect
oncoming seizures but most of the researchers that examine
these dogs don’t think there is anything supernatural in those
abilities. I´ve read several stories recently where dogs
responded to events that may have been spirits. In the first
story the dog reacted to a haze that could have been natural
or could have been supernatural, the second story involved a
dog barking at spirits that even the owner could hear, and the
third took place in a campground in Canada where the dogs
and the owner all saw the spirit before she disappeared.
Yes, Dogs got eyes to see, sometimes what you don't see.
Yes @samsuccess
It's true, dogs really barks on Ghosts and negative negatively energized objects and people.