A demographic study of a Dinka village.

Abstract

Beginning in January 1954 an anthropologist observed the population of the Ageir tribe of Dinkas living in the village called Tir in southern Sudan to gather demographic data. 375 people lived in Tir with an average of 4.46 people living in each clean and suitably spacious hut. The ratio of females to males stood at 106:100. By looking at peoples teeth the anthropologist estimated the mean age to be 65 years old. Since few individuals achieved old age the few that did were respected and safeguarded. All women married and essentially all had reproduced. In addition they had children throughout their reproductive years. Most females 1st married between the ages of 20-29 while most males married after 30. This may have been because of men 1st had to obtain enough cattle to offer for a wife. A high percentage of widows existed especially after 40 (56%). Polygamy and levirate were practiced but not sufficiently enough to assimilate all the widows had died. Further any surviving 60 years olds had lost 45.5% of their siblings. Based on the age structure and mortality rates the anthropologist concluded that the village population was growing rather than stabilizing. The average number of surviving offspring ranged from .14 for 15-19 year women to 3.79 for 30- 39 year old women. This suggested that these villagers practiced birth spacing. It fell after 40 to 2.25 for >60 year old women. Random genetic drift on gene frequencies did not apparently affect this Dinka population. It appeared that natural selection was occurring in the population.