Australian Shepherds, bred initially to herd livestock and be work dogs, have maintained their energetic nature and are happiest when given a task and being played with. These dogs are very intelligent and thrive when performing activities and love to learn new tricks and games. They are easy to train and highly intelligent, but do have a tendency to bark or howl, and use their mouth to communicate by chewing or play-biting, and for this reason usually enjoy activities such as fetch. Aussies are prone to explore and have very high energy needs.