The Australian Shepherd was developed on ranches in the American West in the 1800s, most likely from Spanish and Basque herding dogs crossed with collie types that arrived alongside sheep shipped from Australia. Ranchers prized its stamina and quick thinking, and rodeo shows later made it famous. Aussies are medium-sized, usually 40 to 65 pounds, with a weather-resistant double coat in merle, black or red, often with white and copper trim.
Many Aussies are intelligent, devoted and tireless, and they're happiest when they have work to do. They tend to bond tightly with family and can be reserved with strangers. Without daily exercise and mental effort, that drive can turn into herding kids, chewing or barking, so they fit active adopters who enjoy training. Each dog is different, and an adult's history in a listing says more than breed traits.