“…We add that head-cocking is the fixation of an object in the binocular visual field while rotating the head to various degrees, often when the animal is in a sitting or propped posture so that the rotation is about the rostro-caudal axis of the head itself rather than the body. Head-cocking has been described for the common marmoset, Callithrix jacchus (Stevenson, 1976), but it is by no means unique to this species. It has been observed in other Callitrichidae, Saguinus oedipus and S. fuscicollis, Leontopithecus rosalia (Menzel & Menzel, 1980), and also in prosimians, Galago moholi and Otolemur garnettii (Cantalupo, McCain, & Ward, 2002;Rogers, Stafford, & Ward, 1993), squirrel monkeys, Saimiri sciureus (Rumbaugh, 1968), talapoin monkeys, Miopithecus talapoin (Wolfheim & Rowell, 1972) and even in birds such as owls and nightjars (i.e., in avian species with large binocular fields; Martin, 1990;Payne, 1971).…”