Girls in early childhood increase food returns of nursing women during subsistence activities of the BaYaka in the Republic of Congo

Abstract

Nursing mothers face an energetic trade-off between infant care and work. Under pooled energy budgets, this trade-off can be reduced by assistance in food acquisition and infant care tasks from non-maternal carers. Across cultures, children also often provide infant care. Yet the question of who helps nursing mothers during foraging has been understudied, especially the role of children. Using focal follow data from 140 subsistence expeditions by BaYaka women in the Republic of Congo, we investigated how potential support from carers increased mothers' foraging productivity. We found that the number of girls in early childhood (ages 4–7 years) in subsistence groups increased food returns of nursing women with infants (kcal collected per minute). This effect was stronger than that of other adult women, and older girls in middle childhood (ages 8–13 years) and adolescence (ages 14–19 years). Child helpers were not necessarily genetically related to nursing women. Our results suggest that it is young girls who provide infant care while nursing mothers are acquiring food—by holding, monitoring and playing with infants—and, thus, that they also contribute to the energy pool of the community during women's subsistence activities. Our study highlights the critical role of children as carers from early childhood.

Child and adolescent foraging: New directions in evolutionary research

“…15,18 A wealth of ethnographic data also report that children in subsistence societies provide much of the alloparental care to infants and younger children. [34][35][36][37][38] An additional explanation for the evolution of childhood is the Pooled Energy Model, 39 which can help to explain the constellation of human adult life history traits (short birth intervals, rapid reproduction, high fertility) while accounting for children's productive activities. Within this model, both children and adults draw from and contribute to pooled energy, such that activity budgets are linked across individuals within reproductive units (e.g., families).…”

“…In hunter‐gatherer societies, children commonly forage for fruit, berries, shellfish, insects, honey from stingless bees, small game, birds, and reptiles (Figure 1), which may contribute substantially to their own calorie intake, and to that of others 15,18 . A wealth of ethnographic data also report that children in subsistence societies provide much of the alloparental care to infants and younger children 34–38 …”

BaYaka mothers balance childcare and subsistence tasks during collaborative foraging in Congo Basin

“…Due to the energetic burden of childcare during foraging trips, we expect that the presence of breastfeeding infants in foraging groups constrains mothers from travelling long distance, far away from the village and from exploring in larger range, requires mothers to spend higher energy expenditure and results in lower net food returns. However, BaYaka mothers do not generally travel alone, and they receive childcare support from other members in foraging groups (e.g., carrying or holding infants), which further buffers the cost of infant presence during foraging trips [18]. Hence, we expect that other individuals in foraging groups provide childcare support-either carrying or holding infants while mothers are walking and/or acquiring foods-and, thus, allows mothers to have greater mobility, save their energy, and higher net food returns, by receiving childcare support from group members.…”

“…Due to these traits, mothers face trade-offs in allocations of their investment per child [5, 6, 7, 8, 9], as well as of their time and energy between childcare and other labour [10, 11, 12, 13, 14, 15, 16]. In hunter-gatherer societies where individuals subsist via foraging, balancing the trade-offs between childcare and foraging could be a particularly critical problem for mothers [17, 18]. For example, mothers with young infants tend to reduce time allocated towards food acquisition to increase their time spent in infant care [13, 17].…”

Cooperation and partner choice among Agta hunter-gatherer children: An evolutionary developmental perspective

“…Developmental research is necessary for a complete understanding of behaviour [4], while cross-cultural research, especially in small-scale societies, is required to assess how behaviour develops outside of Western societies, where behaviour may not be representative of current human diversity or our deeper evolutionary history [5]. This ontogenetic perspective may be especially valuable for understanding human cooperation, as even though children are somewhat dependent on provisioning until adulthood [6], they are not merely burdens to adults as they engage in useful cooperative activities such as caring for other children, performing domestic tasks and foraging [7][8][9][10].…”