Australian cattle dog, breed of medium-sized herding dog developed in Australia. It stands from 18 to 20 in. (45.7–50.8 cm) high at the shoulder and weighs about 33 lb (15 kg). Its double coat consists of a soft, dense underlayer and a moderately short, straight topcoat that forms a fringe of slightly longer hair on the back of the forelegs and thighs. The coat may be blue, blue mottle, or red speckled in color. Believed to be the product of crosses among the Australian kelpie, the dingo, and the smooth collie, the Australian cattle dog ranks among the world's best herding dogs. It is sometimes called the Australian heeler, a name derived from the dog's habit of nipping at the heels of stray cattle to direct them back to the herd. The breed is exhibited in the miscellaneous class at dog shows sanctioned by the American Kennel Club. See dog.