Foraging and Menstruation in the Hadza of Tanzania
The Hadza, residing near Lake Eyasi in northern Tanzania, represent one of the last remaining hunter-gatherer populations. Inhabiting the same area as our hominin ancestors and exploiting very similar resources, the Hadza maintain a foraging lifestyle characterised by a sexual division of labour. Studies of their foraging and food sharing habits serve as the foundation to numerous hypotheses of human behaviour and evolution. Data from the Hadza have featured heavily in debates on the sexual division of labour. These debates focus predominantly on men’s foraging, including how and why men provision. Women’s provisioning, on the other hand, is seldom explicitly examined and is often presumed to be constrained by reproduction. This thesis contributes to debates on the sexual division of labour by investigating how a woman’s reproductive status affects her foraging behaviours. Observational data on women’s foraging are investigated from 263 person/day follows (1,307 hours total) across 10 camps between 2004 and 2006. These data present the first quantitative documentation of forager women’s eating and sharing outside of camp. Interview data on women’s reproductive timeline are also analysed from in-depth interviews with 58 women from 9 camps in 2015. Spanning from menarche to menopause, these data offer the first quantitative and qualitative documentation of forager women’s menstruation. The results demonstrate that Hadza women eat and share over 800 kilocalories outside of camp per person/day. They regularly give and receive food, including gifts of honey from men. Breastfeeding women are more likely to give gifts and give more gifts than non-breastfeeding women. When they bring nurslings with them outside of camp, they forage less kilocalories per hour. Post-menopausal women eat less relative to what they forage, are less likely to receive gifts, rest less and forage more than pre-menopausal women. Although Hadza women describe their foraging workload as most difficult during late pregnancy, no significant differences in eating, sharing, resting or foraging are observed for pregnant women. Menstrual data from the Hadza reveal that menstruation is not only culturally relevant to the sexual division of labour, but it is also biologically relevant to current understandings of fertility. The majority (60%) of Hadza women report not doing their normal work during menstruation. They also report menstruation-related taboos for berry picking. The thesis presents an in-depth review of women’s menstruation, from the duration of menses to the menstrual cleaning process.
hunter-gatherers, foragers, Tanzania, Hadza, sexual division of labour, menstruation, menarche, menopause, grandmother hypothesis, hunter-gatherer diet, behavioural ecology, food sharing, reproductive ecology, hunter-gatherer nutrition, foraging, provisioning, central place foraging, energetics, sexual division of labor, life history, menstrual taboo, menstruation taboo, evolutionary ecology
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