Common hippopotamus ( Hippopotamus amphibius ): a survey on the River Djerem, Mbam-Djerem National Park, Cameroon / Hippopotames ( Hippopotamus amphibius ): l'inventaire des populations sur la rivière Djerem, Parc National de Mbam Djerem, Cameroun

AbstractInformation on the population of common hippopotamus ( Hippopotamus amphibius ) in Cameroon is limited. Consequently, management decisions are based on guesses. We surveyed common hippos on the River Djerem in Mbam-Djerem National Park, from April to June 2001 by sailing on the river at 1.5 km/h and counting hippopotamus that emerged to the water surface. We also recorded their tracks along the river banks. We found at least 18 hippos in April and 79 during May–June on the river, suggesting that there were either different numbers at each of the periods or approximately the same numbers, but with individuals responding differently to the physiological and noise stimuli used in the study. However, the observation of numerous fresh outlet tracks of hippos at pools where they were not directly sighted suggests higher numbers on the river during each of the periods. Hunting of hippopotamus in the past for trophies (canines) threatened their survival and accounts for the relatively low numbers observed compared to an earlier survey in the River Bénoué. There are hopes for a future population increase with increased law enforcement in the recently created Mbam-Djerem National Park.