Irish Jack Russells are small terriers with short, often white coats with brown markings. They take their name from breeder Rev. John Russell and were originally bred for hunting foxes.
The Irish Jack Russell has a compact, muscular body and weighs 13 to 17 pounds. Some breeders call for dogs to be from 10 to 15 inches in height, whereas others prefer a slightly smaller range of 12 to 14 inches. Male dogs average 14 inches, and females are 13 inches high at the withers. Jack Russells have a fiery, energetic and loud temperament, which makes training a must, although their natural instincts to hunt cannot be restrained.