^Browsing is a specialized form of grazing. "Graze, verb: 2. Eat growing grass." "Browse, verb: 1. Feed on, crop, (leaves, twigs, scanty vegetation).". Concise Oxford Dictionary 6. 1976. ISBN 0-19-861122-6.
^Estes, R. The Behavior Guide to African Mammals: Including Hoofed Mammals, Carnivores, Primates. University of California Press. 1992: 222–26. ISBN 0-520-08085-8.
^Kingdon, J. East African Mammals: An Atlas of Evolution in Africa, Volume 3, Part B: Large Mammals. University Of Chicago Press. 1988: 256–77. ISBN 0-226-43722-1.
^Eltringham, S.K. The Hippos. Poyser Natural History Series. Academic Press. 1999. ISBN 0-85661-131-X.
^Begon, M., Townsend, C. and Harper, J. Ecology 3. Blackwell Science, London. 1996.[页码请求]