<P> As with dogs from other working breeds, the Australian Cattle Dog is energetic and intelligent with an independent streak . It responds well to structured training, particularly if it is interesting and challenging . It was originally bred to herd by biting, and is known to nip running children . It forms a strong attachment to its owners, and can be protective of them and their possessions . It is easy to groom and maintain, requiring little more than brushing during the shedding period . The most common health problems are deafness and progressive blindness (both hereditary conditions) and accidental injury; otherwise, it is a robust breed with a lifespan of 12 to 14 years . </P> <P> In the 19th century, New South Wales cattle farmer Thomas Hall crossed the dogs used by drovers in his parents' home county, Northumberland, with dingoes he had tamed . The resulting dogs were known as Halls Heelers . After Hall's death in 1870, the dogs became available beyond the Hall family and their associates . They were subsequently developed into two modern breeds: the Australian Cattle Dog and the Australian Stumpy Tail Cattle Dog . Robert Kaleski, who wrote the first standard for the breed, was influential in its development . </P> <P> Australian Cattle Dog has been nicknamed a "Red Heeler" or "Blue Heeler" on the basis of its colouring and practice of moving reluctant cattle by nipping at their heels . Dogs from a line bred in Queensland, Australia, which were successful at shows and at stud in the 1940s, were called "Queensland Heelers" to differentiate them from lines bred in New South Wales; this nickname is now occasionally applied to any Australian Cattle Dog . </P> <P> The Australian Cattle Dog is a sturdy, muscular, compact dog that gives the impression of agility and strength . It has a broad skull that flattens to a definite stop between the eyes, with muscular cheeks and a medium - length, deep, powerful muzzle . The ears are pricked, small to medium in size and set wide apart, with a covering of hair on the inside . The eyes are oval and dark, with an alert, keen expression . The neck and shoulders are strong and muscular; the forelegs are straight and parallel; and the feet round and arched, with small, sturdy toes and nails . </P>

What type of dog is a blue heeler