Adult Nile crocodiles, i.e. at least , are apex predators. While adults can and will consume nearly all types of prey consumed by the younger specimens, as adult crocodiles gain bulk, they lose much of the necessary maneuverability to capture agile prey such as fish and are not likely to meet their dietary needs by consuming small prey and may expel unnecessary amounts of energy, so take them secondarily to larger prey. Primates of various sizes may be taken by subadult or adult crocodiles. In some areas, some number of baboons is taken, such as in Okavango Delta, where chacma baboons ("Papio ursinus") are eaten and Uganda, where olive baboons ("Papio anubis") are taken. No records of them hunting apes (other than humans) have been made, but based on a strong reluctance to cross waters with crocodiles and a violent reaction to the visual stimuli of crocodiles, chimpanzees ("Pan troglodytes") and gorillas ("Gorilla beringei") are thought to consider Nile crocodiles a serious threat. Few details are known about the dietary habits of Nile crocodiles living in Madagascar, although they are considered potential predators of several lemur species. Other nonungulate prey known to be attacked by Nile crocodiles includes aardvarks ("Orycteropus afer") and African manatees ("Trichechus senegalensis").