The Australian Shepherd is a working breed that was developed in the United States, not Australia as its name implies. It has excessive energy and drive and needs a job to do.
The Aussie stands between 18 and 23 inches tall and weighs between 35 and 75 pounds. The working segment of Aussies tends to have slightly shorter coats than the show dogs. Their coat can be one of eight colors: blue merle, red merle, black, or red; each of these may have copper points to create four additional color combinations. The eye color of the Aussie varies as well. The breed may have green, hazel, amber, brown, blue, bi-colored or split eyes.
Aussies come not only in their typical standard form, there are also miniature and toy Australian Shepherds. Many breeders believe that these should be classified as separate breeds, however there are conflicting opinions and some consider them to simply be downsized versions of the Australian Shepherd.
Some Aussies are born with short bobbed tails, some with partial bobs, and others with long, full tails. Historically, those with longer tails have had their tails docked when they were born, although some breeders opt to keep the tail on the dog for the natural look.
The average Australian Shepherd has a lifespan of between 9 to 12.5 years. The most common health issues of the Aussie are eye, dermatologic and respiratory problem. Other conditions include Collie eye anomaly, coloboma, hip dysplasia, Pelger-Huet syndrome, hypothyroidism and nasal solar dermatitis. In particular, Blue merle shepherds of the miniature variety are known for a short lifespan, about half the length of a standard Aussie.
The Australian Shepherd and many other breeds of herding dogs are susceptible to toxicity caused by the heartworm medicine lvermectin. Most dogs do not have this problem; it is caused by a genetic mutation of the MDR1 gene. Tests are available to determine if particular Aussies carry this gene.
The Australian Shepherd is an energetic breed that requires regular exercise and stimulation. The Aussie excels at sports such as Frisbee, agility and herding. It is an affectionate breed, although its overwhelming instinct to work and protect might be frightening to children, small animals and strangers. Some are bred specifically to be family dogs; the work drive of some may override its ability to function in this manner. If an Aussie is not given a job it will often make a job for itself, and it could tend to be destructive, although not purposefully. Aussies also need plenty of human companionship.