Childcare in transition: evidence that patterns of childcare differ by degree of market integration in north-western Tanzania

Women around the world receive help with childrearing, much of which would have come from kin throughout most of human history. Market integration leads to less kin-dense social networks which may transform patterns of allomaternal care. Yet, few empirical studies have quantified the role of market integration in childcare patterns. We test the hypothesis that higher levels of market integration will be associated with (i) lower probability of receiving allomaternal support from kin; and (ii) higher probability of receiving support from non-kin. Using a survey of 808 children under 5 years from Mwanza, Tanzania, we test for differences in childcare arrangements between a less market integrated village and more market integrated town. We consider two types of allomaternal care, low-intensity and high-intensity, from seven sources: fathers, siblings, maternal grandparents, paternal grandparents, maternal aunts and uncles, paternal aunts and uncles and distant/non-kin. In the town, fathers, siblings, and paternal kin had lower odds and distant/non-kin had higher odds of providing care than in the village. Care from maternal kin was not associated with village/town residence. Market integration may disrupt paternal kin-orientated childcare arrangements, but not care from maternal kin, who may overcome greater physical distances to maintain contact. Distant/non-kin appear to substitute for the reduced support from kin in the town. We contribute data on an often assumed, but rarely tested, hypothesis: that market integration is associated with lower likelihood of help from kin, finding mixed support for this hypothesis.

Further behavioural parameters support reciprocity and milk theft as explanations for giraffe allonursing

Suckling of a non-filial calf, or allosuckling, is an extreme case of allomaternal care in mammals. There have been many hypotheses postulated in an attempt to explain this behaviour; however, the supporting evidence differs, together with the conclusions drawn from the investigated variables. Previously, suckling bout rejection was analysed, and the milk theft and reciprocity hypotheses were both determined as the most appropriate explanation of allosuckling in giraffe. In this study, seven hypotheses were tested using different behavioural parameters, namely suckling bout frequency, suckling bout duration, and time spent suckling. It is well-documented that these parameters are associated with various aspects in ungulate biology; for example, suckling rejection typically reflects milk intake and parent–offspring conflict, whereas the suckling bout duration and frequency is associated with social behaviours (affiliation, bonding, social stress). In total, 22 nursing females and 47 suckling calves were observed, in four Czech zoos during a five-year period. The correlation of the observed parameters between the reciprocal female-calf dyads was found to be in line with the reciprocity hypothesis. In addition, non-filial calves tried to steal the milk from non-maternal females, supporting the milk theft hypothesis. Thus, the results support both the reciprocity and milk-theft hypotheses as the most plausible explanation of allosuckling in giraffe, and illustrates the importance of using suckling bout duration and frequency, and the time spent suckling, as behavioural parameters that may aid in explaining the extremity of maternal investment, such as allosuckling.