Why is my dog so hyper all of a sudden – What The Heck Is That? When I adopted Ned Stark (a Jack Russell terrier), he was a calm dog, you can say he was “normal” he didn’t run around for no reason or jump at every noise. His first parent, a retired military officer, passed away and was put up for adoption. I fell in love with him and decided to become his second parent. Fast-forward to some two or three weeks with me, I found myself asking the question “why is my dog so hyper all of a sudden?”.