The Australian Cattle Dog is a medium-sized, short-coated dog that occurs in two main colour forms. It has either brown or black hair distributed fairly evenly through a white coat, which gives the appearance of a red or blue dog. It has been nicknamed a Red Heeler or Blue Heeler on the basis of this colouring and its 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.
As with dogs from other working breeds, the Australian Cattle Dog has a high level of energy, a quick intelligence, and 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. Australian Cattle Dogs now participate in a range of activities beyond the herding they were bred for, including competing with their owners in sporting events and working as assistance dogs.