Exploration into Human Polyandry: An Evolutionary Examination of the Non-Classical Cases

Polyandry has occurred all over the world, among human societies at all levels of social stratification, employing all types of economic strategies. While the classical cases that appear in Southeast Asia among stratified, agricultural societies have been thoroughly studied, very little has been written on the non-classical cases. This thesis surveys fifty-two non-classical cases of polyandry and investigates the conditions under which non-classical polyandry most often occurs. This thesis also tests the following five sets of hypotheses, which were derived from theories related to both classical and non-classical polyandry: the Imbalanced Sex Ratio Hypotheses; the Prolonged Male Absence Hypotheses; the Adult Male Mortality Hypothesis; the Male Economic Production Hypothesis; and the Father Effect Hypothesis. Based on the results of these tests, a few trends seem to be descriptive of the non-classical polyandrous groups in this sample. First, the majority of the societies are egalitarian bands or tribes, practicing hunting and gathering and slash-and-burn horticulture. The presence of polyandry among these groups suggests that polyandry likely existed throughout human evolutionary history. Also, it seems that a skewed sex ratio in favor of males is an important factor contributing to the practice of non-classical polyandry, as are prolonged male absence, high adult male mortality, and high male economic production. Although prolonged male absence and adult male mortality seem to pose similar problems, the data and the case studies in this thesis suggest otherwise. It appears that non-classical formal polyandry is employed as a male reproductive strategy when instances of prolonged male absences occur, in that polyandry may function as a form of mate guarding while the primary husband is away. On the other hand, when adult male mortality is high, it seems that non-classical informal polyandry is a female reproductive strategy, utilized to ensure an investing father for children if the primary father should die. In all cases, however, it appears that non-classical polyandry is one possible solution for men to make the best of a bad situation

A Survey of Non-Classical Polyandry

We have identified a sample of 53 societies outside of the classical Himalayan and Marquesean area that permit polyandrous unions. Our goal is to broadly describe the demographic, social, marital, and economic characteristics of these societies and to evaluate some hypotheses of the causes of polyandry. We demonstrate that although polyandry is rare it is not as rare as commonly believed, is found worldwide, and is most common in egalitarian societies. We also argue that polyandry likely existed during early human history and should be examined from an evolutionary perspective. Our analysis reveals that it may be a predictable response to a high operational sex ratio favoring males and may also be a response to high rates of male mortality and, possibly, male absenteeism. Other factors may contribute, but our within-polyandry sample limits analysis

Women's subsistence strategies predict fertility across cultures, but context matters.

Peer reviewed: TruePublication status: PublishedWhile it is commonly assumed that farmers have higher, and foragers lower, fertility compared to populations practicing other forms of subsistence, robust supportive evidence is lacking. We tested whether subsistence activities-incorporating market integration-are associated with fertility in 10,250 women from 27 small-scale societies and found considerable variation in fertility. This variation did not align with group-level subsistence typologies. Societies labeled as "farmers" did not have higher fertility than others, while "foragers" did not have lower fertility. However, at the individual level, we found strong evidence that fertility was positively associated with farming and moderate evidence of a negative relationship between foraging and fertility. Markers of market integration were strongly negatively correlated with fertility. Despite strong cross-cultural evidence, these relationships were not consistent in all populations, highlighting the importance of the socioecological context, which likely influences the diverse mechanisms driving the relationship between fertility and subsistence

Women’s Subsistence Strategies Predict Fertility Across Cultures, but Context Matters

While it is commonly assumed that farmers have higher, and foragers lower, fertility compared to populations practicing other forms of subsistence, robust supportive evidence is lacking. We tested whether subsistence activities—incorporating market integration—are associated with fertility in 10,250 women from 27 small-scale societies and found considerable variation in fertility. This variation did not align with group-level subsistence typologies. Societies labeled as “farmers” did not have higher fertility than others, while “foragers” did not have lower fertility. However, at the individual level, we found strong evidence that fertility was positively associated with farming and moderate evidence of a negative relationship between foraging and fertility. Markers of market integration were strongly negatively correlated with fertility. Despite strong cross-cultural evidence, these relationships were not consistent in all populations, highlighting the importance of the socioecological context, which likely influences the diverse mechanisms driving the relationship between fertility and subsistence