Hippopotamus amphibius (Linnaeus, 1758)
Photo: Marius Saunders
IUCN Conservation Status:
River hippopotamus = Lower Risk, least concern (LR/lc). The extant
global population is estimated as being between 125 000-150 000.
Pygmy hippopotamus = Critically Endangered (CR)
Hippo are the most unpredictable and moody of all African animals.
Zee-paarden, the Dutch for “horse of the water” was the first citation
on the wildlife of the Cape in Jan van Riebeeck’s journal in 1652. Van
Riebeeck associated the animal with the sea, as hippo was abundant in
nearby marshy lagoons, especially those of Muizenberg and Zeekoeivlei.
There were also large numbers to be seen in the Berg River. Several
other names followed; “zeekoe”, sea-horse, sea-cow and, in the 1700’s,
those in the Nile River were called “Nylperd” or Nile-horse. Eventually
the name hippopotamus or hippo was given to the animal. The name
hippopotamus is derived from the Greek for horse “hippo” and from river
“potamus”. The “Behemoth” animal referred to in the Bible was an
extinct hippo species.
The oldest known true
hippopotamid is the genus Kenyapotamus found in Africa 20-8 million
years BP. Fossils dating back 20 million years BP were found in Kenya.
Hippopotamidae are believed to have evolved in Africa and then spread
across Europe, through Asia to Indonesia. They did not cross into the
Americas. From 7.5–1.8 million years BP Archaeopotamus, an ancestor of
the modern hippopotamus Hippopotamus and Hexaprotodon (also referred to
as Choeropsis), lived in Africa and the Middle East. Scientists
disagree as to whether the modern pygmy hippopotamus is a member of
Hexaprotodon the Asian hippos from the Pliocene, or of Choeropsis from
the older Pleistocene.
As many as three species of the dwarf Malagasy hippo became extinct on
Madagascar during the Holocene. Two species ranged in Europe and the
British Isles Hippopotamus antiquus and H. gorgops, but were extinct
before the last Ice age.
Only three species survived of which two are found in Africa, the first
being the hippopotamus or river hippo.
Hippopotamus amphibius with five subspecies:
- H. a. amphibius found in the Nile River from Sudan to the north of
Tanzania, and down the Rift Valley to Mozambique. It was recently
eradicated in Egypt. Book a holiday to Sharm el Sheikh
- H. a. kiboko found in the Horn of Africa, Kenya and Somalia
- H. a. capensis distributed from Zambia to South Africa
- H. a. tschadensis found throughout western Africa to Chad
- H. a. constrictus of Angola, the southern Democratic Republic of Congo and Namibia,
The second species is the pygmy hippopotamus Hexaprotodon liberiensis, formerly Choeropsis liberiensis with two subspecies
- H.l. liberiensis the Liberian pygmy hippopotamus
- H.l. nigeriensis the Nigerian pygmy hippopotamus
The last surviving species is the Madagascan pygmy hippopotamus
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A large amphibious mega-herbivore, with a large, barrel shaped body and
short, stout legs like an enormous pig. The head is broad and well
developed and supports a massive mouth with jaws that open up to 50 cm
wide. The river hippopotamus has four incisors and the pygmy
hippopotamus six. Other extinct hippos had only two incisors.
Other than some sparse, brush-like hair on the chest, lips, neck, ears
and the tail end, the skin is virtually naked, smooth and moist, a dark
greyish-brown with a pink tinge. It appears pinker when the hippo is
out of the water due to a red, slimy, viscous fluid secreted by glands
in the inner skin layer, giving rise to the myth that hippos sweat
blood. The nostrils contract and close when a hippo is submerged for up
to 6 minutes. Hippo can charge at speeds of up to 35 km/hr on land, and
in water they cannot swim but walk or gallop on the bottom at speeds of
up to 22 km/hr. Adult bulls are much larger than cows, weighing up to 2
500 kg. After the elephant the hippo and white rhino is currently the
second largest living terrestrial animals. A body mass of 770-950 kg is
reached at 7-8 years, of 1 400 kg at 11 years and >2 000 kg after 20
The pygmy or dwarf
hippopotamus is much smaller with a mean adult body mass of 160-190 kg
for cows and 200-280 kg for bulls and a mean shoulder height of 82 cm.
The snout is smaller and narrower than the river hippo and the hide is
bluish-black, sometimes with a dark green tinge.
Comparison To Man
Hippopos do not possess
horns but have ivory tusks similar to those of the elephant and
warthog. The canines of both jaws and the incisors of the lower jaw
grow continuously. They are popular in the ivory trade as, unlike
elephant ivory, hippo ivory does not change colour with age. The lower
incisors grow forward horizontally while the lower canines grow
vertically upwards in a half circle. The upper canines grow vertically
downwards and are rudimentary compared to the lower canines. The
largest trophy is not necessarily found in the oldest hippo as tusks
are inclined to wear after reaching 20 years.
Permanent river systems
or water rich environments such as dams or wetlands. These must have
deep pools with gradually sloping bottoms, dry sandbanks and at least a
5 km radius supply of suitable grazing. It can be found from the rivers
of the equatorial tropics to desert environments such as the Nile River
in the Sahara, the Orange River in the Richtersveld and the Fish River
in the Namib. Hippos rapidly change the structure of tall grass stands
to their preferred short grass grazing. Hippos readily move up and down
watercourses between temporary pools. They climb the steep slopes of
mountains and ridges to an altitude of 2 400 m in search for food and
suitable habitat and may remain there for many years if left
undisturbed. In contrast, the pygmy hippopotamus prefers forest-like
Feeding & Nutrition
The activities are
restricted mostly to the night hours between 20:00-4:00 and 7-8 hours
of feeding per day. They move distances of up to 30 km with a mean of
5-8 km per night on land. Hippo roam an average distance of 3-5 km from
water to a maximum of 10 km. Most daylight hours are spent lying either
in the water or on dry sandbanks. Adult bulls sometimes sleep under
thick bushes on land. Hippopotami are monogastric, non-ruminant
herbivores. The diet consists 90% of palatable, short sweet grasses and
10% reeds and dicot herbs.
A partly selective roughage feeder consuming plant matter with high
crude-fibre content, but rich in carbohydrates and protein. Short
grasses less than 12 cm is preferred, although taller grass may be
consumed until the habitat has been transformed into a lawn-like stand.
A mean of 40 kg fresh grass material, approximately 10% of its body
mass, is consumed per adult hippo per night. In captivity they can be
maintained on 1-1.5% of their body mass per day. When environmental
conditions deteriorate and food and water are not available, they often
survive in muddy wallows for weeks by lowering their metabolic rates
and relying on the stored body fats in the skin.
The large 3 m long stomach has four chambers divided into two blind
sacs by a septum, contributing to a slower digestive process than that
of ruminants. This slow rate, enhanced by calm resting after rapid
feeding on land at night, results in an improved digestion and
absorption of ingested dietary nutrients. The hippo lacks the caecum
found in hindgut digesters such as the elephant.
Hippo are semi-gregarious
living in small family groups in the water during daylight hours. At
night the groups split up and roam and graze as individuals or couples
that are mainly mothers and calves.
The social structure are:
- family groups of 5-30 individuals, including 2 bulls >20 years
(one is dominant), 5-10 cows >11 years, several sub-adult females
4-8 years, 4-8 sub-adult males 4-10 years and calves <4 years. The
sub-dominant bull and the sub-adult males avoid conflict with the
dominant bull by keeping to the perimeter of the family. They are not
tolerated by the cows. At the first sign of a challenge to its
leadership the dominant bull immediately attacks aggressively
- bachelor herds of 4-8 individuals, of young bulls >10 years, not
associated with family groups, that inhabit their own water pool
- post mature solitary nomad bulls occupying smaller bodies of water.
Photo: Doug Lee
Territorial behaviour of dominant bulls, associated with a family herd,
is restricted to the water and immediate shoreline. Social or
hierarchical behaviour does not exist inland.
Hippopotami are non-static and move regularly in search of alternative
habitats during annual environmental changes. Nightly movements of up
to 30 km can occur between dams. When water sources are depleted,
families form temporary mass herds of up to 150 individuals and share
the remaining pools. During this time the social order is disrupted,
creating enormous confusion among the bulls that attack and kill the
young. These aggregations break up when the last of the water has
evaporated and individuals become single nomads that often die if
alternative resources are not quickly found.
Single groups consisting of one adult bull and 1-3 family members are
often kept in small remote dams on ranches. This is a recipe for
disaster as there is no alternative habitat or space to support the
social structure of the additional male offspring in the system. This
can result in fights to the death or to the escape of hippo bulls into
|Hippopotamus information table
|Adult body weight:
|Adult shoulder height:
|Age of sexual maturity
|Age of social adulthood (1st mating)
|1st calf born at
|Post maturity age (last mating)
|Gender ratio: Natural (all ages)
|Gender ratio: Production (all ages)
|Mating ratio: Natural (adults)
|Mating ratio: Production (adults)
Absolute minimum number needed
Smallest viable population size
|Spatial behaviour: Home range
|Spatial behaviour: Territory range
|Large stock grazing unit (adult):
Dietary ratio (grass):
3.3 per animal (99% of diet)
|3.3 per animal (99% of diet)
|Browsing unit (adult):
Dietary ratio: (browse):
|5.38 per animal (1% of diet)
|5.38 per animal (1% of diet)
|Maximum stocking load
|8 animals per 1000 ha
grazing & 3 animals per 100 m river front
|Minimum habitat size required
|Annual population growth
|5-37% (Mean 14%)
|Optimal annual rainfall
|Optimal vegetation structure:
Woody canopy cover:
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