The Jack Russell terrier is smart, full of energy and plenty of mischief. There are smooth coats and rough coats. I prefer the smooth coat because they are easier to look after and they look smarter.
Jack Russells are working dogs and the like to work or to play, definitely a bundle of unstoppable energy.
I think this might be a Russell Terrier, related to the Jack Russell, but with shorter legs and a stockier chest.