The Jack Russell Terrier is a compact, high-drive working breed developed in 19th-century England by Reverend John Russell for fox hunting. Typically 10–15 inches tall and 13–17 pounds, they are predominantly white with tan or black markings and a smooth, broken, or rough coat.

Bold, intelligent, and tireless, Jack Russells need vigorous daily exercise and mental work. Without it they become noisy or destructive. A strong prey drive means they often chase small animals and may not suit homes with cats or pocket pets. They bond closely with their people yet remain independent and stubborn, so they do best with consistent, early training and an experienced owner.

Secure fencing is essential; they are notorious escape artists. They shine in agility, earthdog, and other sports. With enough outlets they are lively, loyal, and entertaining companions rather than lap dogs. Expect 13–16 years of spirited companionship if their needs are met.