The Aders’s Duikers (Cephalophus adersi) of Mnemba Island, Zanzibar: A Study of the Behavior and Diet of a Critically Endangered Species

Cephalophus adersi, commonly known as Aders\u27s duiker, is an extremely rare, near endemic species to Unguja Island in the Zanzibar archipelago. It is a member of the suborder Ruminantia and is considered part of the red duiker family. C. adersi is critically endangered, and although it is protected by Zanzibari law, its population numbers have plummeted over the last thirty years due to hunting as well as habitat destruction and fragmentation. This study examines the behavior and ecology of a small population of Aders\u27s duikers living on Mnemba, an island off the coast of the northeastern tip of Unguja. Four individual duikers were identified based upon unique scars and markings and were followed over the course of thirteen days. This study evaluates their tolerance for researcher presence, relationships between duikers, diet composition and habitat, as well as interactions and competition with the Suni antelope. It was found that each of the four duikers had different levels of tolerance for close proximity to humans at the start of the study, and that they did not seem to become more habituated during the course of the study. The possible relationships between the duikers studied included a mother and calf as well as one male female pair bond. The Aders\u27s duikers of Mnemba were observed eating seven different species of plant, two of which were also consumed by the Suni antelope. This study found that careful control of the Suni antelope population in combination with the expansion of suitable habitat area for the Aders\u27s duikers on Mnemba Island could both help increase the number of this endangered duiker living on Mnemba and contribute to the conservation of the species as a whole