Russell is a big dog with a small body. If you compare his origins to those of today's Fox Terriers, Jack turns out to be closer to his age-old ancestors, created to hunt and work in the den, who needed persistent training.

It is the working qualities that have given today's Jacks their intelligence, worldview, physical attributes, fantastic character, unmatched athleticism, and mobility. All this makes him a great pet and companion.

He is always alert and ready for the next discovery or adventure. He looks at you with his inquisitive intelligent eyes and kind of asks: "What does my master want?" He adores his master and tries to show it with all his behavior. He adores kisses, sitting in his arms, and loves affection and tenderness. He can make quick decisions, be confident, and never be shy, shy, or indecisive. This is such a composite of the most diverse and sometimes incompatible qualities.

"Flying doggie" is one of the epithets that Jacks have been awarded by the people. Why "flying"? 

Look at him, he never stands with all four paws on the ground, he always bounces, literally floats above the ground, like an aerial gymnast, in a kind of mesmerizing dance. He is rarely nervous or aggressive, almost always friendly and active. He is small in size, dressed in white with small red or black markings.