“…One pattern of early weaning, or reduced maternal investment in offspring, was associated with maternal inability to maintain offspring growth or lactation due to low resource availability or poor physical condition. Indeed, early weaning (e.g., vervet monkeys, Cercopithecus aethiops: Lee, 1984Lee, , 1987Hauser and Fairbanks, 1988), unresponsive and neglectful parenting (e.g., vervet monkeys, Hauser, 1993;human: Belsky et al, 1991; also see review in Maestripieri and Carroll, 2000), infant abuse and abandonment (e.g., humans: Daly and Wilson, 1984;Hrdy, 1999), and infant mortality (e.g., barbary macaques, Macaca sylvanus: MĂ©nard and Vallet, 1993;humans: Daly and Wilson, 1984;Hrdy, 1999) have all been associated with poor maternal condition and/or poor resource availability. In such cases, females may sacrifice their current offspring's fitness in favor of maternal survival and the possibility of producing offspring in the future.…”