Letcher, Owen "The Geographical Distribution of Big Game in Northern Rhodesia," Proceedings of the Rhodesia Scientific Association, No. 10 (1910)

I cannot discuss the rhinoceros and the hippopotamus without some reference to an animal which is most emphatically stated by the natives to frequent some of the deepest pools and rivers of the Congo-Zambesi watershed ... I do not say that I am convinced as to the existence of a huge water rhino in Central Africa, but I do say this, that, in my opinion, it is by no means unlikely that the "Chimpakwe," as the Awisa term it, is something very much more material than a myth. I have asked many old chiefs in North-Eastern Rhodesia about the "Chimpakwe," and they have all assured me that this mighty two-horned amphibian was, many years ago, an inhabitant of the Luangwa river. One old Awisa headman told me that his father had shot one with a gun which an Arab hunter had given him. The natives stated that since the water in the Luangwa has decreased in volume and height, the chimpakwe has disappeared, but that he might to-day be found in the deeper waters of the Luapula, and in one or two deep pools in the northern part of North-Western Rhodesia.