Despite its name, the Australian Shepherd dog was mostly developed in California. Its ancestors were Basque sheepdogs in Spain related to the European breed currently called "Pyrenean Sheep Dog," and these did go along with Basque sheepherders to Australia, where they interbred with Collies. The results accompanied flocks of sheep to California in the mid-1800s, where the type was referred to as "Aussie Sheepdogs," but the breed was standardized to breed true on American ranches. (The breed should not be confused with the Australian Cattle Dog, which was truly developed in Australia and even has dingo in its ancestry.) A unified standard was adopted by the two or three clubs promoting the breed in 1976, and the American Kennel Club recognized them in 1992.
Australian Shepherds, or "Aussies," were exclusively working dogs until the past few decades. They are described as "workaholics" and are good at herding cattle or other livestock in addition to sheep. They are fiercely devoted to their owners and definitely one-person/one-family dogs, reserved around strangers (or without much socialization with new people, like my mother's, they end up actively hostile to strangers). They are very energetic and need a lot of exercise if they are companion dogs rather than actively herding, but always eager to please, and this energy makes them tireless workers in not only herding, but drug detection, hearing-ear work for the deaf, search and rescue work, and even Frisbee-catching shows. (I know my mother's Secret Puppy will play fetch for much longer than one would believe a thick-coated dog would want to in the Florida sun.) Without the chance to exercise, their energy can lead them to destructive behaviour such as digging and chewing their owner's belongings. (Or as Liz Palika put it, " An Aussie with no sheep to herd, ducks to drive, or cattle to round up will herd the kids instead.") Also, since they were bred to dominate sheep, they are likely to test their owner's dominance at first. With a firm, assertive attitude toward them, they take well to training, though; they are very intelligent dogs, as they would have had to be to manage herding. Desmond Morris calls Aussies "a rather silent dog," and this may be true when they're on the field with sheep, but the ones I know are quite prone to bark at people and other dogs. The breed also has what Morris describes as "a strange call that is somewhere between a bark and a howl" (and boy, when you have two adults and three puppies in a house, it may start out in-between but it goes into full-blown howling when they want to get their human out of bed).
Australian shepherds have a tremendous variety of coat colors -- the ones my mother and her boyfriend have include Rambo, who is white with very pale tan patches; Secret Puppy, Jazzie, and Secret Puppy Junior, who are black with white underside and leg markings; Kelly, who is charcoal gray; and Rambo Junior and Little Girl Amber, who are brown. (In official breed standards, the allowed colors are listed as "blue merle, black, red merle, red-all with or without white markings and/or tan (copper) points." I guess Rambo couldn't make it as a show dog.) All have thick coats, and a few of them have a noticeably longer neck-ruff of fur. (Different sources disagree about the amount of grooming they need; my experience agrees with Liz Palika that they will leave a coating of shed fur over the whole house, but some of my mother's leave a lot more hair in the grooming brush than others.) Rambo is blue-eyed, but this seems to be fairly rare as all the others, even those descended from Rambo, have dark brown or amber eyes. Their ears are triangular but usually flop forward. Some of their tails are naturally bobbed; the rest usually have the tail docked in early puppyhood (though you can still see the stump wagging on the ones I know) as it is with many herding dogs to keep the tail from collecting burrs or getting shut in gates.
Aussies look a lot like border collies, but tend to be bigger and heavier than their part-ancestor. Border collies generally have longer tails and have ears that stick straight up, while Aussies' flop forward.
They are generally 18-23 inches (46-58 cm) in height and 35-70 pounds (16-32 kg) in weight; in the 1960s a Miniature Australian Shepherd was bred from the smaller members of the standard breed and these "Mini Aussies" are usually 13-18 inches (33-46 cm) tall and 15-30 pounds (7-14 kg). The miniature breed is also known as the North American Shepherd. Another variant of the Aussie is called the Basque Shepherd (though it too was created in the U.S.) and differs from the Aussie only in being bred for normal (i.e., long and flowing) tails rather than natural bobtails. The reason behind this variant was that some breeders felt that breeding for bobtails led to spinal problems in the dogs.
Aussies are occasionally prone to eye
problems or hip dysplasia
; people acquiring puppies are encouraged to make sure that both parents are free of these problems. The white dogs are particularly likely to have genetic defects.
Morris, Desmond. Dogs: The Ultimate Dictionary of Over 1,000 Breeds. North Pomfret, Vermont: Trafalgar Square Publishing, 2001.
Dogsitting for my mother's pack of Aussies.