Known also as "Blue or Red Heelers". They have a mix of Australia's native wild dog, the Dingo, the Dalmatian, the Collie, and the Kelpie in their background. The Australian Cattle Dog is a medium sized well-muscled dog. They have wedge-shaped heads and prick ears that stand upright when the dog is alert. This breed is extremely energetic and intelligent, as it was bred for long days of work in the fields. They need a good deal of exercise to be kept happy, they can be destructive when bored. They are very loyal to their owners, and wary with strangers. They make good watch dogs as well as guard dogs, as they will fiercely protect their family and property. Males measure up to 20 inches at the shoulder and weigh from 33 to 50 pounds.