Bongos (Bongo Drums) are a percussion instrument made of two small drums of different size attached to each other. The larger drum is called a hembra (Spanish for female) and the smaller drum is called a macho (Spanish for male). Bongos are usually made of wood, metal or composite materials attached by a thick piece of wood. The heads are usually made of animal skin, such as goatskin or water buffalo skin, or synthetic material. Bongo drums are held between the knees with the larger drum on the right, and are traditionally played by striking the drumheads with the fingers and palms. Some contemporary compositions require the drums be played with sticks or brushes.