Jack russel terriers are so very hyper, and its the way most of tem are. There are some though that are very sweet and calm. They do get obsessions very easily! its quite funny to watch! my grandmother and two of my aunts have jack russel terriers(they're all related in some way) and they are the weirdest bunch! One of the dogs likes to attack the plastic ducksa they keep in the pool. I luv these dogs to pieces!!