Australian Shepherd, or Australian Cattle Dog, is a
generic term for a "
breed" that has been produced over the last two centuries from a combination of varying parts
Smithfield Collie,
Dingo,
Scotch Collie,
Dalmatian,
Bull Terrier,
Kelpie and unknown other breeds. Due to their rich
genetic background, they come in many shapes, sizes and colors, but are imperfectly divided into two groups: "red heelers," and "blue heelers." Coloring is usually
mottled, the blue group displaying white, black, brown and tan fur that blends into a general bluish color if you squint your eyes just right. Red heelers have genuine red
tint thrown in, generally at the expense of white fur. The term "
heeler" is used to recognize the strong
herding instincts in these
dogs, and most of them are still used in working situations, particularly in
Australia (of course),
New Zealand,
Mexico, and the western
United States and
Canada. Those not in working situations will herd whatever's around -
cats,
people, even
cars! Regardless of color or size, Australian Shepherds have exceptionally strong hindquarter and shoulder muscles, a large head and powerful jaw, and very high
intelligence and
adaptability.
They also have a strong pack mentality, and are very sensitive to who is part of a pack and who is not, and the power structure within the pack. Their loyalty to the pack (consisting of humans, dogs and other animals) is undying, but they are suspicious of and often antagonistic toward outsiders. They are often able to gauge the mood of a room before humans can. As far as training goes, no other dog I know of learns as quickly, and they pick up immediately on signals, intended or otherwise, included in tone of voice and body language. Although smart and respectful of authority, they also seem to have a deeply ingrained sense of what Buddhists call "right action," and won't immediately comply with orders that don't seem to fit the situation.
Although size within the "breed" does vary, Australian Shepherds tend to be medium to large, but have as much energy as smaller dogs. (Popular to contrary belief, large dogs are typically better city dogs, and small dogs usually need a lot more space.) An Australian Shepherd that does not get the opportunity to spend it's energy will tend to grow more assertive with his owner(s), and over time may even develop serious psychological problems. But given a loving home and proper upbringing, these dogs are actually the most mentally healthy I know of, probably due to their aforementioned genetic diversity. When further cross-bred with other working dogs, particularly collie breeds, results are even more impressive, and the Australian Shepherd "mutt" can live as long as 20 years, sometimes more. In other words, if you're going to get one, make sure you're aware of the commitment involved.
Photos of Australian Shepherds can be found at the following urls:
http://www.blueheeler.com/merle.htm
http://www.hitnheel.com/dogs.htm