duetting of territory owners, and many direct observations of duetting neighbors were observed to cause the territorial owners to move towards the calling, where they sometimes confronted each other across a small space. There is some evidence that titis not only can determine sex from a long call but can identify duetting individuals, so it should perhaps not be surprising that a resident pair could distinguish a recording from a live monkey and move away from it. A human-raised and newly matured female black titi on first shouting, attracted the resident forest group to come closer until they became accustomed to her presence, although they always answered her calling with their duetting, later neither coming closer nor moving away. The female's vocalizations sometimes attracted several individual males in short order, which attempted to duet with the female. Since the female had been raised by humans, she did not show interest in duetting with the newly appeared males nor in establishing a relationship with them, and the males eventually desisted and left. The only exception to this was one male which attempted to establish a relationship during two years before giving up and leaving during an accidental 26-day absence of the female when she became inadvertently lost in the forest. Some vocalizations of black titi are listed here: Morning duet – the most commonly heard vocalization of the pair, singing in duet, complex and utilized to defend territory; it is interchanged with neighboring groups as counter-singing Danger peep – various soft, high-pitched peeps but sometimes low intensity, advising of danger; very difficult to localize Purr – sounds very much like a cat's purr; used by all members of the group to show contentment, affection or request for food, grooming or contact; Rough growl – given by young animals when complaining of rain or when greeting adults Sharp scream – when fighting to express extra disgust Play growl – low, gargling growl used in play and changing in tone, terminating in interrogative tone Soft whine – especially young animals but also adults when requesting something of another such as food or while grooming another Bark – loud, sharp and sudden bark when molested by the unwelcome close presence of other larger primates such as Lagothrix, Cebus, Ateles or raptors. Individuals of both sexes occasionally mark their chests with pungent wadded leaves, rubbing the leaf up onto the throat and chin to the