The Australian Cattle Dog (ACD), or simply Cattle Dog, is a breed of herding dog originally developed in Australia for droving cattle over long distances across rough terrain. This breed is a medium-sized, short-coated dog that occurs in two main colour forms. It has either brown or black hair distributed fairly evenly through a white coat, which gives the appearance of a 'red' or 'blue' dog. It has either brown or black hair distributed fairly evenly through a white coat, which gives the appearance of a 'red' or 'blue' dog. Among the most popular activities for an Australian Cattle Dog is dog agility. It is ideally suited for navigating obstacle courses, since as a herding dog it is reactive to the handler's body language and willing to work accurately at a distance from the handler. A larger survey of 100 deceased dogs yielded a mean longevity of 13.41 years with a standard deviation of 2.36 years. The median longevities of breeds of similar size are between 11 and 13 years.