Alloparental Behavior

Alloparental behavior, defined here as care of infants by individuals other than the mother, is relatively common in primates (Nicolson 1987). In primates, it reaches its most extreme levels in the South American marmosets and tamarins (family Callitrichidae). Popular literature on these small monkeys frequently describes the mothers as carrying the infants only during nursing, with fathers and other group members caring for infants the rest of the time. Though these popular reports exaggerate the limited role of the mother in infant care, they emphasize the long-standing recognition of nonmaternal infant care in callitrichids. For this reason, they are a valuable group in which to examine the factors controlling mammalian alloparenting, or cooperative infant care.

The central question addressed in this review is, “Why do individuals other than mothers care for infants?” Clearly this question can be addressed on a number of levels from the proximate or physiological factors that affect interactions with infants (e.g., Dixson 1982; Pryce, Döbeli, & Martin 1993; for review see Pryce 1993) to the functional role that social and environmental interactions and constraints may play (e.g., Epple 1975; Price 1991, 1992a, 1992b; Tardif, Carson, & Gangaware 1992; Tardif, Harrison, & Simek 1993) to the possible adaptive advantages of such behavior (e.g., Rylands 1982; Goldizen 1987; Price 1990a; Baker 1991). This review will focus on the functional and adaptive explanations for alloparental behavior in callitrichids.