While whales eventually returned to the sea, the anthracotheres, ancestors of the hippopotamus, are thought to have descended from an ancestor shared with the whale.
The reserve now has several important conservation species, including lion, elephant, giraffe, black and white rhinoceros, hippopotamus and cape leopard.
This might be the historical explanation for "kifaru" rhinoceros, "kingugwa" spotted hyena, and "kiboko" hippopotamus (perhaps originally meaning stubby legs).