Pa. Garber et Sr. Leigh, ONTOGENIC VARIATION IN SMALL-BODIED NEW-WORLD PRIMATES - IMPLICATIONSFOR PATTERNS OF REPRODUCTION AND INFANT CARE, Folia primatologica, 68(1), 1997, pp. 1-22
This paper explores relations of ontogeny, life history strategies and
patterns of infant care in 11 species of small-bodied New World monke
ys. Analysis of these data suggests that differences in the social sys
tems of Aotus, Callicebus, Saimiri, Callimico, Saguinus, Leontopithecu
s, Cebuella and Callithrix are closely tied to both the costs of repro
duction and to the ontogenetic requirements of maturing young. In Saim
iri, both rapid prenatal body weight and perinatal brain growth result
in relatively high metabolic costs to breeding females. These costs,
coupled with minimal nonmaternal assistance in caregiving, appear to f
avor a reproductive strategy that limits offspring production to a sin
gle birth at 2-year intervals. In contrast, tamarins and marmosets are
capable of producing twins twice in the same year. Prenatal investmen
t in each offspring is relatively low, and the potentially high postna
tal costs of nursing 2 infants are minimized by the evolution of a soc
ial system involving extensive extramaternal caregiving. Cooperative i
nfant care in callitrichins (tamarins and marmosets) serves to distrib
ute the metabolic costs of infant ontogeny among several group members
. Callimico is also characterized by a high reproductive output, with
females capable of producing a single infant twice during the year. In
fants continue to grow rapidly after weaning. Patterns of infant devel
opment in Callimico are similar to those found in tamarins and marmose
ts and support a close phylogenetic relationship among these taxa, Aot
us and Callicebus are characterized by an alternative strategy. In the
se taxa, a monogamous mating system is associated with paternal certai
nty, male parental care, and provisioning of the young. The transfer o
f male energetic resources to a single offspring allows night and titi
monkeys to maintain a comparatively short interbirth interval (1 year
). Ecological and social factors, such as predation and feeding compet
ition, do not appear to adequately explain much of the observed variat
ion in infant development and preadult growth rates in these platyrrhi
nes. Instead, reproductive strategies are strongly linked to ontogenet
ic patterns and life histories.