HUMAN EVOLUTION Vol. 16 - N. 3-4 (225-229) - 2001 Urbani B. Escuela de Antropologfa, Universidad Central de Venezuela and Departamento de Antropologfa, Instituto Venezolano de Investigaciones Cientfficas. Mailing address: Apartado 47.028, Caracas 1041-A, Venezuela. Telefax: ++58 2 987 06 21. Email: urbani @ cantv. net Key words: Food-washing, "Nut" cracking, Rubbing, Peeling, Spontaneity, Problem-solving Food-washing among wedge-capped capuchin monkeys (Cebus olivaceus) Four cases of spontaneous food-washing and others novel behaviours are reported for Cebus olivaceus. The individuals observed are either wild or captive born members of wedge- capped capuchin monkey groups from two zoological parks in Caracas, Venezuela. Those cases seem to represent the resolution of particular and circumstantial problems, rather than indication of learning, transmission or imitation processes. Introduction Food-washing has been under special consideration among non-human primates behavioural studies. The occurrence of this behaviour in the wild had been reported for Old World primates, particularly for Macaca fuscata (Itani, 1958; Kawai, 1965; Nakamishi et at., 1998) has been considered a cultural behaviour, and later evaluated by Visalberghi (1995: 36-40). Wheatley (1988) indicates food-washing and rubbing, as a possibly of learned behaviour in wild Macaca fascicularis. Visalberghi and Fragaszi (1990b) also reports food-washing behaviour by captive Macaca fascicularis. For primates of the New World, Visalberghi (1990) and Fragaszi & Visalberghi (1990a) indicate that the capuchins monkeys presents great interest in novel and innovative problem solving behaviours. In fact, captive tufted capuchin monkeys (Cebus apella) were reported as food-washers by Fragaszi and Visalberghi (1990b). Rubbing behaviour had been reported for free-ranging Cebus capucinus (Panger, 1998), while nut cracking behaviour in the wild was reported for Cebus apella (Struhsaker and Leland, 1977; Izawa and Mizuno, 1977) and in captivity by Visalberghi (1987). In our report, we discuss spontaneous food-washing associated with rubbing and "nut" cracking behaviours among captive Cebus olivaceus. Material and Methods The primates under consideration are members of Cebus olivaceus groups of two zoological parks in Caracas. The first group consists of 11 individuals of the Parque del Este (PE) from which we recently reported the use of tools among their members (Urbani, 1999). The second group is represented by 8 individuals of the Parque E1 Pinar (PP). In both cases, the primates are closely associated to water ponds because they live in