other species suggests the importance of palms as "key species" and the lack of importance of Ficus in such habitats as gallery forests in the llanos of Colombia and Venezuela, contrasts with their high importance in more fertile habitats like Manú. White-fronted capuchins take advantage of almost any water source, drinking water from tree holes when available, but also drinking from brooks and springs when necessary. During the driest season in Vichada the group studied by Defler went to the ground every day to a water seep from under a huge boulder, which was the only water source available in their home range. Reproduction White-fronted capuchins are polygamous. The male mounts the female, holding her legs with his hind feet, and copulates with her for a few minutes. Although the time of gestation is unknown, it is probably around 160 days like the tufted capuchin. Usually one infant is born. Observations of a newborn in El Tuparro National Park showed the process by which the newborn discovered the appropriate position for riding on the mother. Newborns ride oriented sideways over the mothers' shoulders, but during the first days the baby holds on to any part of the mother such as the base of the tail, the tail, the legs, and the arms before discovering and learning that the position over the shoulders is best and most secure. After several weeks the baby makes the change from the sideways position over the shoulders to riding on her back. All the members of the troop are interested in the newborn, and they take advantage of any opportunity to examine and look at its genitals if the mother permits it. With time the baby begins to climb up on other members of the troop, including the adult males who are interested in protecting the little one. Playing behavior is principally with a companion, and all members of the troop from the alpha male, the mother and all young members of the group solicit play with the young one. Social structure Adult males are notably tolerant of each other in the group, but they are very aggressive towards males of other groups. Defler observed intergroup aggressive behavior among Humboldt's white-fronted capuchins in El Tuparro, which resulted in one group fleeing towards the central parts of their territory. Alpha males seem to exercise a "control position" at the center of the group, since all members