Print PageConsanguineous marriages, which are still a common cultural habit in East Sumba of eastern Indonesia, have been associated with mortality and morbidity. This type of marriage has special significance related to some deleterious health effects including low survival rate and genetic abnormalities, nonetheless, Sumbanese prefer to mate with their relatives. Their traditional customs have been pushing cross-cousin marriages based on their ancestral clan system. As most human populations have inhabited heterogeneous environments, younger generations recently have mating with non-consanguineous partners. The aim of this study is to elucidate the long-term survival mechanisms of a Sumbanese population and effects of consanguineous marriages on offspring survival using a method of ecological anthropology. The demographic data were collected by interviews in August 2008 during a field work in a village of East Sumba, East Nusa Tenggara Province, Indonesia. A total of 95 married women participated in this study. Total numbers of her children, year of each birth, year of each death, and marriage type with a father of each child were interviewed by the author. Marriage type was categorized into two, consanguineous and non-consanguineous. Degree of kindred was ranged from first cousin to unknown degree relationship but which was strictly recognized by their clan members.
Results/Conclusions
Among 95 mothers, 52 females (55%) had mating consanguinity. We found a weak generational trend of marriage type among different generation of mothers categorized into five; before 1969, 1970s, 1980s, 1990s, after 2000 of her married year (Chi-squared test, /p/=0.08). Out of total 310 offspring, 33 offspring were died before he/she grow up 5 years old. This survival rate was 87.8% (23 dead / 166 survived) in consanguineous marriage and 91.7% (10 dead / 111 survived) in non-consanguineous marriage (Chi-squared test, /p/=0.28). Non-consanguineous marriage likely had offspring with higher survival after five years. However, mean numbers of offspring having survived over 5 years for one female in
consanguineous marriage were significantly greater than those in non-consanguineous marriage (Student’s t test, /p/=0.02). Consanguineous marriages might decrease the survival rate of the offspring who lived over 5 years old, but lead to high fertility in Sumbanese. These results indicate that Sumbanese consanguineous marriage had a benefit to persist prosperity of descendants despite of relatively higher mortality rate. Their classical kinship system ruled by lineage relationship had effects on social structure including human survival to maintain the Sumbanese population as ecological adaptation.
