Population Structure of the Common Hippopotamus (Hippopotamus amphibius) in the Luangwa River, Zambia

Abstract

Population structure of the common hippopotamus (Hippopotamus amphibius Linnaeus 1758) in the Luangwa Valley, eastern Zambia was assessed during the period [2005][2006][2007][2008]. Field observations and laboratory examinations were used to classify hippos in age groups. Chi-square Test of age group composition showed a significant difference in the percent proportion of age groups in the population ( 2 = 57.98, DF = 6,  = 0.05, P< 0.001). Calves one year old and less were not represented. Younger groups 'iii' and 'v' comprised only 15 percent of the population. The remaining 75 percent were older age groups vii -xix mainly comprising mature and senescent individuals. The age structure was biased towards older age groups. Skewed age distribution in favour of older age groups was an indication of a declining population growth rate. More research is required to investigate factors responsible for the decline in population growth rates.