This is Hailey.
She came to me when she was about a year old. Her previous owner could not handle her. Jack Russells are very smart dogs but bark a lot if not trained well.
They like to have your hand in their mouth too and will bite you when playing. They love to growl and sound very fierce when playing but you can see their tails going a mile a second when they're playing.
I don't recommend these dogs to homes with small children. They will bite when they play and for them it's pretty normal. You can't ever have more than two dogs in the household when you have Jack Russells either because they will likely fight and breaking up a dog fight is no fun and if you have children, well you see why these beautiful, smart dogs must be carefully supervised at all times. For the owner who has the time to devote to these wonderful dogs they are excellent guard dogs, pest control, and terrific companions.
As proof of how smart they are Hailey would "smile" like this whenever I came home from work or when she was getting into something she isn't supposed to be getting into. She is standing on the kitchen table in this picture which she obviously is not supposed to be doing. Her tail is wagging hard and I set her on the floor. She tore up the chair to the right too. They are a handful.
Also as evidence that they are not good dog for children she would snap and growl at any of the other dogs who tried to come near me until she was greeted first. I had Hailey for about 10 years until she passed on peacefully one night.