“Every morning, the male and female [Siamang] burst into spectacular duets. [...] Since the song reflects their marriage, the more beautiful it is, the more their neighbors realize not to mess with them. A close-harmony duet communicates not only "stay out!" but also "we're one!" (p. 177)” PrimatesAnimal BehaviourPair BondPrimatologySiamangs Book:Are We Smart Enough to Know How Smart Animals Are? Source: Are We Smart Enough to Know How Smart Animals Are?