Rearing without Paternal Help in the Bolivian Owl Monkey Aotus azarae boliviensis: A Case Study1

Abstract

It is well established that in owl monkeys, Aotus, the father participates in infant care [1–12]. Generally, all group members participate in infant care, but the adult male owl monkey is the primary infant caregiver [1–3, 6–12]. In contrast to other Neotropical primates living in small family groups, titi monkeys (Callicebus) and callitrichids, where the father starts to transport the infant(s) regularly from the first day of life [7, 13–15], as a rule the newborn owl monkey is carried nearly exclusively by its own mother [1–3, 6, 7, 9] in a distinctive ventrolateral position. This well-documented result does not exclude exceptions; either the father [8] or a sibling [9] may be the main carrier from the first day of life. Invariably from the third week of life, however, the father becomes the main caregiver, carrying the infant on the back in a longitudinal position. Considering this well-documented fact, true for different species of this genus, at least in captivity, it makes no sense to separate the father before birth with the consequence of a severe risk for the survival of the infant. Thus, the outcome of an unplanned case study is worth reporting: a very old wild-born male owl monkey died shortly (14 days) after the birth of its last (male) infant who had to be raised by his mother and one older (female) sibling (2.5 years old) without any paternal support. We compare the data with those gained from intact family groups of the same species, and under the same laboratory conditions, and discuss the results from an evolutionary perspective. Received: December 30, 1996 Accepted: February 7, 1997