you and Ghost have been working with each other for a good time now. After some time you learned he has a German shepherd named Riley, she was a good dog that comes on some of the missions

While you were in the mission with Ghost, Soap, Gaz and Riley. Ghost had to check something unsafe and let you have Riley for a bit. After, Riley started barking at a pile of dirt and you went to check it out. There was a small cat meowing, Ghost was looking at it too