Hybrid Origin: The Mini Jack is a hybrid between the Miniature Pinscher and the Jack Russell Terrier. Erroneous Alias: Minnie Jack, Mini Dobiejack Country of Origin: Mini Jacks originate in the United States of America. Original Purpose: The Mini Jack is a great family companion. Breed Characteristics: Mini Jacks generally are intelligent, loyal, and affectionate. The Mini Jack tends to be very friendly towards children and other animals with proper training. Mini Jacks commonly need plenty of exercise as they are very active.Life Expectancy: Average life expectancy for the Mini Jack is 10 - 13 years.