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Hippopotamus amphibius (Hippopotamus)
seekoei [Afrikaans]; Grossflusspferd [German]; hippopotame [French];
kiboko [Swahili]; imvubu [isiNdebele] [isiXhosa] [isiZulu] [siSwati];
kubu [Sepedi] [Sesotho] [Setswana] [Lozi];
mvuu, ngwindi [Shona]; mpfubu, mpfuvu [Xitsonga]; mvuvhu [Tshivenda];
unvuva [Yei];
!Khaos [Nama] [Damara]
Life
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Eukaryotes >
Opisthokonta >
Metazoa (animals) > Bilateria > Deuterostomia >
Chordata > Craniata > Vertebrata (vertebrates) >
Gnathostomata (jawed vertebrates) > Teleostomi (teleost
fish) > Osteichthyes (bony fish) > Class:
Sarcopterygii (lobe-finned fish) > Stegocephalia
(terrestrial vertebrates) > Reptiliomorpha > Amniota >
Synapsida (mammal-like reptiles) > Therapsida > Theriodontia
> Cynodontia > Mammalia (mammals)
> Placentalia (placental mammals) >
Laurasiatheria > Ferungulata > Cetartiodactyla (even-toed ungulates and cetaceans)
> Whippomorpha > Ancodonta > Hippopotamidae
Identification
Hippopotamus derives its name from the Greek for “river
horse”. It is a large, barrel –shaped animal with naked skin, grayish black in
colour with pink tinges at the folds, near the ears and eyes and on the
underside. The legs are short and stocky, ending in four toed feet. The head is
massive with a broad muzzle with large tusk like incisors and canines. The huge
mouth is opened wide to expose the tusks in display and combat. As an adaptation
to its amphibious way of life the nostrils are located on the top of the snout.
Size
Height at shoulder 1.5 m; weight range 1 000 - 2 000
kg (male) and 1 000 – 1 700 (female).
Dental formula
I C P M =
36-40
Distribution and habitat
A patchy but widespread distribution South of the
Sahara. In the southern African subregion it occurs in the extreme northern and
the eastern areas. It requires sufficient water to allow submergence and
prefers permanent water bodies with a sandy substrate.
General behaviour
The hippo is semi- aquatic and spends most of the day lying
in water or on the river bank. They emerge at night to graze and may travel as
far as 30 km during a night. They travel to the feeding grounds along easily
recognized set pathways. An adult hippo can remain submerged for 6 minutes, they
have a trotting swimming action and “trot” along submerged pathways underwater.
This phenomenon can be clearly seen in the Okavango delta where the underwater
pathways are clearly visible from the air. When submerged only the nostrils,
eyes and ears can be seen.
Skin glands exude an oily secretion over the body (called a
“blood sweat” because of its pinkish colour) this protects the skin from drying
out.
Hippo normally occur in herds (or schools) of 10 to 15
animals, although larger groupings and solitary animals are also quite common.
Herds consist of cows, sub-adults and calves, with a dominant bull. The bull
marks his territory by scattering dung with rapid flicking of his tail. The
territories tend to be narrowest at the water and widen out on the feeding
grounds. The territoriality is also the strongest at the water. Bulls are
aggressive to anything entering their territory, including other hippos, other
animals and boats or canoes. It is for this reason that the hippo has earned the
reputation as the “biggest killer” in Africa, as they will intercept canoes and
are occasionally involved in instances where unobservant swimmers are attacked.
In areas where hippo occur naturally in the rivers, the local people are very
wary and take extreme care to determine if any hippo are in the immediate
vicinity.
Food
Hippos are selective grazers, feeding predominantly
on grasses.
Reproduction
After a gestation period of 22 months, hippos give birth on land or in shallow water the calf
weighs about 30 kg is kept separate from the herd for the first fortnight. The
calf is born hindlegs first and is capable of going into deep water shortly
after birth. The calves are threatened by crocodiles and large predators such as
hyaena and lion. Mothers are protective of their young and usually graze in the
close vicinity. Like adults young hippo cannot float, when in the water they
will often rest their heads on the backs of other hippo or sit on their mother’s
back.
Life span
60 years and more than 80 years in captivity
Conservation
The conservation of hippo depends on it having access
to grassland and water. They are protected within national parks but outside the
boundaries they are hunted for meat and their large canines and incisors. Hippo
do conflict with humans as they raid and damage crops and are also occasionally
responsible for killing people. Currently while there are conservation concerns
in certain parts of Africa and their total numbers are declining, they are not
regarded as threatened.
Text by Denise Hamerton
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