Other even-toed ungulates include giraffes, hippopotamuses, warthogs, giant forest hogs, red river hogs and bushpigs. Among the large mammals include the Big five, cheetahs, wildebeest, giraffes, hippopotamuses and various antelopes. Thanks to genetic studies, elephants, rhinoceroses and hippopotamuses are classified as separate clades altogether. However fossil evidence of large archaic species of rhinoceroses, hippopotamuses, and lions have been discovered. Although fossil records of ancestral forms of rhinoceroses, hippopotamuses, and lions have been found. This exhibit is home to hippopotamuses and pygmy hippos. Fauna included dwarf elephants, megacerines and hippopotamuses, and giant avians, otters and rodents. The River Umuvumba, contains hippopotamuses, and Nile crocodiles. The shallow water is frequented by Nile crocodiles and hippopotamuses. In other parts of the world, elephants and hippopotamuses may kill crocodiles defensively. Horses, cattle, capybara, hippopotamuses, grasshoppers, geese, and giant pandas are graminivores. Other semi-aquatic mammals include beavers, hippopotamuses, otters and platypuses. The common mammals are mona monkeys and pygmy hippopotamuses. The river is home to hippopotamuses and crocodiles. "H. minor" is the smallest hippopotamus of all known insular hippopotamuses.