Many foraging societies tend to restrict group size. Different societies employ different mechanisms to limit group membership, but how do they accomplish this? This page is dedicated to exploring the differences and similarities concerning female roproductive adaptations among foraging groups in today’s world.
Overview:
Managing reproduction is an important aspect of foraging culture. Group size, gender preference of offspring and female ability to care for offspring all contribute to a perceived need to control fertility. Group size is normally kept to a relative number and there are many reasons for such restrictions. For many hunter-gatherer groups, food is not easily obtained causing distribution to be problematic if the number of mouths to feed is greater than the amount of food available. Some groups handle this problem by encorporating a fission-fussion social order; when resources are scarce the group fissions and fuses when resources are abundant. Another mechanism is managing reproduction. Foraging societies have very unique means of managing reproduction, yet at the same time can share many of the same devices. However, nature can also play a role in reproduction, or the lack thereof.
The !Kung and Fertility
The !Kung, the prototype for hunter-gatherer studies, have been analyzed constantly on their way of life, including their means of reproduction. According to Melvin Konner and Marjorie Shostak, the !Kung are a non-contracepting and non-abstaining culture whom have low fertility and high mortality, yet their population sees an increase by year. This presents a base for inquiry because it is in direct oposition to the laws of reproduction. Although neither contraception nor abortion was evidently practiced, a healthy fertile !Kung San woman - if she had the good fortune to survive until menopause - was likely to produce only about five children. Despite her best efforts, one of these five, on average, would die before its first birthday, of malaria, perhaps, or some other disease. Even more heartbreaking would be the deaths of two older children, nurtured through several years only to succumb to disease or accident or violence while still unmarried and childless. A girl who lived to reproduce - and only 48% of female babies did so - could expect to raise successfully one son and one daughter who would marry and produce children of their own (Fielder, King 2008).
!Kung eland ceremony for the menarche
Children always accompany their mothers so they don't get lost in the wilderness. The carrying sling represents a major technological invention which makes it possible for woman gatherers to both look after their children and also bring back enough food for the groups to survive well without a regular kill. Carrying young children can become back-breaking when food is gathered miles away and has to be carried back as well. The !Kung have a proverb 'Women who have one birth after another like an animal have a permanent backache!' and the back-load hypothesis has been advanced as an explanation of birth spacing. !Kung mothers may be thus balancing the optimum survival of the children they do have partly by the mother's endocrine system making sure the mothers also replace their reserves. By contrast with a !Kung mother who may carry an infant nearly 5,000 miles overall by the age of 4, Hadza women who travel shorter distances to forage and can thus also more often leave a child in camp have a shorter inter-birth span (Fielder, King 2008).
!Kung women gathering with their children on their backs.
What causes low fertility?
!Kung women reach menarche, first menstral cycle at which time fertility is possible, at about sixteen and a half years, about the same for women all around the globe. First birth is at age nineteen and a half and last birth in the late thirties. !Kung women have an average birthing interval of forty-eight months, roughly four years. A long interval between births and a high rate of infant mortality, between 10 and 20% in the first year, contribute to low fetility.
There is also a connection between resource acquisiton and reproduction. If the female body is placed under unusual amounts of stress it can affect her reproductive capabilities. Hence, if a woman is heavily pressured to increase resource returns she may fall into a state of amenorrhea and be unable to reproduce. There are many causes of amenorrhea but in the case of foragers it is most likely due to insufficient nutrition and over-exertion.
A study done by Frisch and Janet McArthur of the Massachusetts General Hospital in Boston showed that the amount of body fat must be above a certain minimum for the onset of menstruation and for its maintenance after menarche. During a !Kung woman's lactational period, which can last for three to four years per child, they need an extra 1,000 calories a day. She may not have enough resources to sustain a suitable body fat composition for ovulation to occur. "The most convincing explanation for the exceptionally low fertility of the !Kung themselves, however, is an interaction effect between lactation and dietary stress" (Handwerker 85: 15).
Due to the absence of ovulation, it is very unlikely for a !Kung woman to conceive during lactation. This fact has resulted in the term "Nature's Contraceptive". W. Penn Handwerker stated that, "long periods of intensive breatfeeding lead to long periods of postpartum infecundability." The long periods of infecundability can also be seen as a birth-spacing mechanism. Female foragers are many times unable to acquire enough resources to support breastfeeding of two children. The effects of caring for two dependant offspring would be catastrophic on both child and mother. She would be unable to produce enough milk to support both children as well as unable to procure enough food to sustain herself.
An example provided by Hayden states that "By placing women of child-bearing age in positions where they can be easily overworked, they can be pressured by the community to control reproductive activities and infant survival" (Kelly 1995: 301).
Controlling reproduction is in the best interest of the whole society because it ultimately controls the amount of food that goes to each person. Controlling reproduction restricts population growth and forager societies cannot afford a large population due to resource variability.
Trade-Offs between female food acquisition and child care
Even though female food acquisition is an area of considerable interest in hunter-gatherer research, the ecological determinants of women’s economic decisions in these populations are still poorly understood. The literature on female foraging behavior indicates that there is considerable variation within and across foraging societies in the amount of time that women spend foraging and in the amount and types of food that they acquire. It is possible that this heterogeneity reflects variation in the trade-offs between time spent in food acquisition and child care activities that women face in different groups of hunter-gatherers. In this paper we discuss the fitness trade-offs between food acquisition and child care that Hiwi and Ache women foragers might face. Multiple regression analyses show that in both populations the daily food acquisition of a woman’s spouse is negatively related to female foraging effort. In addition, nursing mothers spend less time foraging and acquire less food than do nonnursing women. As the number of dependents that a woman has increases, however, women also increase foraging time and the amount of food they acquire. Some interesting exceptions to these general trends are as follows: (a) differences in foraging effort between nursing and nonnursing women are less pronounced when fruits and roots are in season than in other seasons of the year; (b) foraging return rates decrease for Ache women as their numbers of dependents increase; and (c) among Ache women, the positive effect of number of dependents on foraging behavior is less pronounced when fruits are in season than at other times of the year. Lastly, in the Hiwi sample we found that post reproductive women work considerably harder than women of reproductive age in the root season but not in other seasons of the year. We discuss how ecological variation in constraints, the number of health insults to children that Hiwi and Ache mothers can avoid, and the fitness benefits they can gain from spending time in food acquisition and child care might account for differences and similarities in the foraging behaviors of subgroups of Hiwi and Ache mothers across different seasons of the year. Valid tests of the explanations we propose will require considerable effort to measure the relationship between maternal food acquisition, child care, and adverse health outcomes in offspring (Hurtado 1992:185).
Hadza grandmother babysitting while the women are out looking for food
Infanticide among the !Kung
Today, Bantu law prohibits infanticide. According to most studies, the !Kung very rarely practiced abortion and infanticide, but in traditional times when it occured it was used as a means of spacing births and in cases of congenital deformity and twinning. In cases of twinning, one sex was not preferred over the other. The !Kung do not observe strict postpartum sexual taboos regarding intercourse, therefore abortion and infaticide are the best means for dealing with unwanted or troublesome births. This leads back to the contention that it is quite difficult to care for two nursing infants at one time.
References Cited
Fielder Christine, King Chris
2008 Culture Out of Africa. Sexual Paradox: Complementarity, Reproductive Conflict and Human Emergence
Hurtado, A Magdelena
1992 Trade-Offs between female food acquisition and child care among hiwi and ache foragers. Human Nature vol 3 185-216.
