The Koolie is Australia's quiet achiever of the stock-dog world. It has worked sheep, cattle and goats here since the 1800s, bred from British working collies and the German working dogs that came with settlers. The name is said to come from "the German's Coolies". The breed has never chased show ribbons. The Koolie Club of Australia breeds for working ability rather than looks, so Koolies come in a useful range of shapes: small, agile dogs for yard and transport work, taller dogs with stamina for droving, and steady types for sheep.
Many Koolies wear a merle coat, a marbled pattern of darker patches, though solid black, red and chocolate dogs are just as genuine. That merle is beautiful and needs responsible breeding. Two merle parents can produce double merle puppies, which have a real risk of sight and hearing problems. A good breeder pairs a merle with a solid-coloured dog and can show DNA test results for both parents.
At home, a Koolie is a devoted, eager partner that wants a job. It might be herding, agility, tracking or a serious daily training habit. Without one, all that intelligence and drive tends to go into chasing, circling and rounding up whatever moves, including children and the cat. Give a Koolie work and a routine and you get a loyal, capable mate. Give it a backyard and nothing to do and you'll both be frustrated.