Domesticated orangutans can imitate people to do some simple tasks, such as sweeping the floor with a broom, shoveling the earth with a shovel, eating with tableware, beating invading enemies with sticks and so on. Some orangutans can also thread needles, stand upside down, ride small bicycles, use musical instruments, drive tractors and help people do simple housework. In addition, they also use sign language to express some simple languages.