I am so sorry I had to put my dog to sleep a month ago she was sick with cancer. I don't have any tangible evidence but my other dog started barking and growling in the air over her bed. She would ONLY bark at my other dog like that. I have no doubt my dog saw her sister I feel crazy for typing that but it is true. Also my husband took our dog to the park and I was all alone in the home and I heard the sound of the dogs metal tags hitting the metal water bowl. So I have no doubt that they cross over or stay with you.