Classification and Range
The hippopotamus (hippo) belongs to the family Hippopotamidae, which includes two species, the hippopotamus (H. amphibius) and the pygmy hippopotamus (Choeropsis liberiensis). The hippo lives in western, central, eastern and southern parts of Africa.
The hippo inhabits rivers and lakes, and wallows during the day. At night, hippos graze in short grasslands.
Hippos have a head and body length of 10.8-11.3 feet (3.3–-3.45 m). Males are normally larger and weigh more than females.
Hippos range in weight from about 1,764-7,056 pounds (800-3200 kg).
Hippos can live up to 45 years in the wild, up to 49 years in captivity.
In the wild: Numerous species of short grasses
At the zoo: Grass hay, romaine lettuce trims, pellet feed and occasional treats, which include apples, carrots and seasonal pasture grazing
Females become sexually mature between the ages of 7-15, but usually by the age of 9. Males become sexually mature between the ages of 4-11, but usually by age 7. Mating season coincides with the dry season when hippo populations are concentrated at water sources. Mating usually occurs in the water, and females are sometimes completely submerged. As a result, females must push their heads above water to take occasional breaths of air.
Hippos reproduce about every two years in the wild. Gestation lasts from 190-210 days, with births occurring during the rainy season. The female gives birth to her offspring on land or in shallow water. Newborns weigh about 93 pounds (42 kg). The mother and her offspring will stay separate from the herd for 10-14 days after birth. She weans the offspring about 8 months after birth.
Female hippos with offspring usually live in groups of 10-15 individuals, but researchers have noted groups of up to 150. Adult males are solitary but sometimes form bachelor groups. Solitary males are usually territorial and their territories often include a group of females with their offspring. Males maintain their territories for 4-8 years and during this time, hold the exclusive mating rights to resident females. Non-territorial males do not breed. At a lake, a male's territory consists of a strip of water and the adjacent land, approximately 820-1,640 feet (250-500 m) in length. At a river, territory is usually about 164–-328 feet (50-100 m) in length.
In Greek, hippopotamus means "river horse." This name suits the hippo, which spends its days in or near water. At night, aquatic groups of hippos disperse, as individuals go to shore, and females and their infants stay together. Hippos follow onshore trails marked with dung piles to grazing fields, feed for about 5-8 hours, then return to the water before dawn or early in the morning.
Hippos are excellent swimmers but prefer to amble along the bottom of slow-moving or stagnant water. An adult hippo can stay under water for up to five minutes. Since hippos are such large animals, they greatly affect their habitats. In water, hippos deposit tons of excrement, which fertilizes plants and feeds animals, such as fish. However, hippos are not as beneficial on the land. They overgraze grass fields and their big feet trample the wet ground around lakes and rivers thereby causing erosion. To help maintain hippo habitats, countries such as Uganda have organized hippo management culling programs. These programs monitor and maintain hippo and other herbivore populations to preserve the land.
Hippos are hosts to many creatures. Birds, such as hammerhead storks and cattle egrets, use hippos as perches for fishing while hippos stand in water. Birds pick flies, ticks and other insects off the skin of hippos. These birds do the hippos a favor by removing the pesky bugs. Another creature which hippos play host to is the Oculotrema hippopotami, a parasitic fluke found on 90% of all hippos' eyes. In the water, certain fish species eat algae and other deposits off the hippos' skin.
Location at the Zoo
Woodland Park Zoo's two female hippos can be viewed in the African Savanna, usually sleeping in their pool. If the hippos are not in or near their pool, they may be eating browse on the beach area or resting in their barn (especially on colder days). Other animals that can be viewed in the African Savanna zone are giraffes, African wild dogs, African lions, gazelles, and zebra.
Hippopotamuses are listed as a vulnerable species, primarily because humans have excessively hunted hippos for their meat, fat, ivory teeth and hides. Unlike elephant tusks, hippo teeth do not yellow with age. This makes hippo ivory more desirable on the black market. Humans also hunt hippos for sport, because the hippos damage cultivated fields when trampling and eating crops, or because they are very dangerous to humans. The last of the wild hippos are unnaturally compressed into remaining suitable habitats.
Woodland Park Zoo Is Helping-With Your Support!
The hippopotamus is one of the most iconographic of the African savanna species. Their presence on the savanna immeasurably bolsters eco-tourism. In zoos, they help demonstrate the interdependency of all species. Breeding programs that maintain healthy captive animals are essential for the future of the species. Respect for traditional lifestyle and educational support empowers local populations to help save their ecosystem and the hippos dependent upon it.
Each in-situ project supported by the zoo aims to provide a broad, holistic approach to conservation, by encompassing research, education, habitat and species preservation. This includes comprehensive, cooperative strategies to link the needs of animals with the people who share their ecosystems.
How You Can Help!
Woodland Park Zoo contributes information to the captive breeding, husbandry and public awareness of this intriguing species. The effort to save African mammals requires cooperation and support at the international, national, regional and individual levels. You can help in this cause. Join and become active in Woodland Park Zoo and other conservation organizations of your choice. Let your elected representatives know your views on protecting endangered species and wild habitats. Please do not buy products made from wild animal parts.
Contact Woodland Park Zoo at firstname.lastname@example.org to find out ways you can support conservation programs at the zoo. Learn other ways you can help conserve wildlife and the habitats they require for survival by visiting our How You Can Help page.
Sources and Suggested Reading
Macdonald, David. 1984. The Encyclopedia of Mammals. Facts on File Publications, New York, NY. 895 p.
Wild, Wild World of Animals. 1976. Elephants and Other Land Giants. Time-Life Television. 128 p.
Little, Douglas, David Francis and Donna Rawlins. 1995. Ten Little Known Facts About Hippopotamuses. Houghton Mifflin Company, New York, NY. 48 p.