The Hippopotamus
Western Cape Safari Guide: Common Hippopotamus
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Family: Hippopotamidae
Genus and Species: Hippopotamus amphibius
Hippopotamus
The name Hippopotamus comes from the ancient Greek for “river horse”, though in reality, these massive mammals are more closely related to whales and dolphins than horses.
The Common Hippopotamus is the third-largest land mammal, after elephants and white rhinos, and an unmistakable presence in Africa’s rivers and wetlands.
Appearance
Hippos have enormous barrel-shaped bodies, short stocky legs, and an immense head with a broad, square mouth.
Their skin is mostly hairless, thick, and greyish-purple in colour. Specialised glands secrete an oily pinkish fluid, sometimes called “blood sweat,” which acts as a natural sunscreen and antibacterial barrier.
Despite their rotund appearance, hippos are powerful and agile both in water and on land.
Hippos are herbivores, feeding almost exclusively on short grasses. They graze at night, travelling up to 5 kilometres from water to find grazing sites, consuming up to 40 kilograms (88 pounds) of grass each night. Contrary to popular myth, they do not eat fish or meat.
Size
Common Hippos are impressively large:
Shoulder Height:
- 1.3–1.6 metres (4.3–5.2 feet)
Body Lenth:
- 3.3–4.2 metres (10.8–13.8 feet)
Weight:
- Males: 1,500–3,200 kilograms (3,300–7,000 pounds)
- Females: 1,300–1,800 kilograms (2,900–4,000 pounds)
Diet
Plains Zebras are grazing herbivores, feeding mostly on:
Short to medium grasses
Occasionally leaves, bark, and herbs during dry seasons
Unlike many antelope, zebras can thrive on coarse, lower-quality forage, enabling them to range widely and occupy grasslands that other grazers avoid.
Location and Habitat
Common Hippos are found throughout sub-Saharan Africa, inhabiting rivers, lakes, floodplains, and wetlands.
They spend most of the day submerged in water to stay cool and protect their sensitive skin from the sun.
Behaviour
Hippos are semi-aquatic and spend up to 16 hours a day submerged. They are highly social, forming groups called pods, bloats, or sieges, typically consisting of 10–30 individuals, though aggregations of over 100 can occur.
Dominant bulls maintain territories in water, which they mark with dung-spraying displays, while females and young move freely between groups.
Despite their slow appearance, hippos are aggressive and unpredictable, especially when defending young or during territorial disputes. On land, they can sprint up to 30 km/h (19 mph) over short distances.
Challenges and Threats
Although still widespread, Common Hippos face significant pressures:
Habitat loss from agriculture and water extraction
Poaching for ivory (their canine teeth) and meat
Human-wildlife conflict, as they damage crops and can be dangerous to people
Their conservation status is Vulnerable, with populations declining in parts of their range.
Territory
Males maintain water territories for breeding, while females have overlapping home ranges. At night, all hippos leave the water to graze, returning before dawn.
Breeding
Females give birth in shallow water after an 8-month gestation.
Calves are born underwater and must swim to the surface to take their first breath.
Young hippos nurse underwater and stay close to their mothers for protection.
FAQ - Frequently Asked Questions About Hippos
Estimates suggest 115,000-130,000 individuals remain across Africa.
Grunts and grumbles: Most common sounds, used to signal territory, presence, or alarm.
Wheeze-honks or honks: Loud calls often used by males to assert dominance or during confrontations.
Roars or bellows: Can carry over long distances, especially at night, to warn rivals or attract mates.
Underwater vocalisations: Hippos can make clicking, honking, or growling sounds underwater to communicate with other hippos while submerged.
These vocalisations help maintain social bonds, warn of danger, and establish dominance within a herd.
They can run up to 30 km/h (19 mph) over short bursts on land.
In the wild, they can live 40-50 years; in captivity, up to 60 years.
Young hippos are called calves.
Strength and Size: Adult hippos can weigh 1,500–3,200 kg (3,300–7,000 lbs) and have powerful jaws with large tusks capable of crushing boats or attacking humans.
Territorial Behaviour: Hippos are highly territorial in water, aggressively defending their riverbanks, lakes, and channels.
Speed on Land: Despite their bulk, they can run up to 30 km/h (19 mph) over short distances on land.
Aggression: They often attack without warning if they feel threatened or if humans or boats come between them and their young.
Fatal Encounters: Hippos are responsible for more human fatalities in Africa than lions, leopards, or elephants, primarily due to their aggression and unexpected attacks.
In short, hippos are not to be underestimated – while they may look slow or docile, they are extremely dangerous both in water and on land.
Hippos are not part of the Big Five because the term was originally coined by big-game hunters to describe the five most difficult and dangerous animals to hunt on foot: lion, leopard, elephant, buffalo, and rhinoceros.
While hippos are extremely dangerous, they spend most of their time in water, which made them less of a challenge to hunt on land compared to the other Big Five species.
They were therefore excluded from the original Big Five list, even though they are aggressive, powerful, and respected animals.
Today, the Big Five is more about iconic safari species and conservation focus, but hippos remain outside the group due to this historical hunting context.
Hippos have a complex, three-chambered stomach, but they are not true ruminants like cows or antelope.
Their stomach allows them to ferment plant material and digest tough grasses, but they do not chew cud.
This digestive system is adapted to their mostly aquatic lifestyle and grazing habits, allowing them to extract nutrients efficiently from large amounts of coarse vegetation.
Hippos cannot breathe underwater, but they are superbly adapted to aquatic life.
They hold their breath for up to 5 minutes while submerged.
Their nostrils are located on top of their heads, allowing them to breathe while mostly underwater.
Hippos automatically close their ears and nostrils when fully submerged to keep water out.
They typically surface every 3–5 minutes to breathe but can stay longer if necessary.
This adaptation allows them to graze in water, stay cool, and avoid predators while still being able to breathe efficiently.
Hippos are herbivores, primarily grazing on land rather than feeding in the water where they spend most of their day.
Diet: They mainly eat short grasses, consuming about 35–50 kg (77–110 lbs) per night during their nocturnal feeding.
Feeding pattern: Hippos usually leave the water at dusk to graze and return by dawn.
Occasional browsing: In dry seasons, they may eat leaves, fruits, or fallen vegetation if grass is scarce.
Yes, hippos have large tusks, which are actually elongated canine teeth rather than true tusks like those of elephants.
Size: Tusks can grow up to 50 cm (20 inches) long in adult males.
Purpose: They are used primarily for fighting rivals, defending territory, and protecting their young, rather than for feeding.
Danger factor: Hippos’ tusks, combined with their powerful bite, make them extremely dangerous in confrontations.
Hippos cannot technically swim in the way many other aquatic animals do.
Instead of swimming, they move by pushing off the riverbed while walking or running along the bottom.
They can stay submerged for up to 5 minutes, surfacing periodically to breathe through their nostrils.
Their bodies are buoyant enough to float, but their movement in water is mainly walking or bounding along the river or lake floor, not true swimming strokes.
This unique adaptation allows them to graze in water, stay cool, and avoid predators, even though they spend most of their time submerged.
Adult hippos have very few natural predators due to their size, strength, and aggressive behaviour, but calves and weaker individuals are more vulnerable.
Adults: Almost no predators; lions or large crocodiles may occasionally attack, but this is rare and dangerous for the predator.
Calves: Young hippos are more at risk and can fall prey to lions, crocodiles, and hyenas, especially if they stray from the protective presence of the herd.
Humans: Today, humans pose the greatest threat through poaching and habitat encroachment.
Hippos rely on herd protection, aggression, and their aquatic lifestyle to stay safe from most threats.
Some hippos appear pink or reddish due to a combination of skin pigmentation, sun exposure, and natural secretions:
Skin colour: Hippos’ skin is naturally a greyish-brown, but it can look pinkish, especially around the eyes, ears, and back, where the skin is thinner or more exposed.
Sweat-like secretion: Hippos produce a natural reddish-orange oily fluid, sometimes called “blood sweat,” which acts as a sunblock and antibacterial layer. This can give their skin a pink or reddish tint in sunlight.
Young hippos: Calves often look lighter or pinker because their skin is thinner and less pigmented than adults.
So, the pink hue is not a sign of health issues, but a natural adaptation that protects their skin and keeps them cool in harsh sunlight.
Common hippo (Hippopotamus amphibius)
- Found throughout sub-Saharan Africa in rivers, lakes, and swamps.
The species most people think of when they hear “hippo.”
Pygmy hippo (Choeropsis liberiensis or Hexaprotodon liberiensis)
Much smaller and more reclusive, weighing 180–275 kg (400–600 lbs).
Native to forests in West Africa, mainly Liberia, Sierra Leone, Guinea, and Ivory Coast.
Less aquatic than the common hippo, spending more time in dense forest and swamps.
The common hippo dominates rivers and lakes, while the pygmy hippo is rare and secretive, often making it difficult to spot in the wild.
A hippo’s mouth is incredibly large and powerful, designed for both feeding and defense:
Mouth opening: Can open up to 180 degrees, allowing a gape of about 1.2 meters (4 feet) wide.
Teeth: They have large tusks (elongated canines) up to 50 cm (20 inches) long, plus sharp incisors and molars for grazing.
Purpose: The huge mouth is used for territorial displays, fighting rivals, and defending the herd, as well as eating large quantities of grass.
This massive gape, combined with their 1,800–2,000 psi bite force, makes hippos extremely formidable despite their mostly herbivorous diet.
Yes, hippos are highly territorial, especially in water, where they spend most of their time.
Water territories: Adult males defend stretches of river, lake, or lagoon, controlling access to females and prime resting spots.
Aggression: Males use yawning displays, tusk threats, and actual attacks to keep rivals away.
Land behaviour: On land, hippos are less territorial; they mostly follow feeding routes at night, but males may still defend nearby grazing areas if necessary.
Herd protection: Territorial males help protect females and calves, making water territories critical for survival and reproduction.
Preferred habitats: Slow-moving rivers, freshwater lakes, lagoons, and floodplains with nearby grasslands for grazing.
Geographic range: Common throughout countries such as South Africa, Botswana, Zimbabwe, Zambia, Uganda, Tanzania, and Mozambique.
Hippo milk appears pink because of the natural reddish-orange secretions their skin produces, often called “blood sweat”, which mix with the milk when the calf nurses.
Skin secretions: Hippos secrete a fluid that acts as a natural sunscreen and antibacterial layer, which has a reddish or pinkish tint.
Milk coloration: When calves suckle, small amounts of these secretions can mix with the milk, giving it a pinkish hue.
Normal occurrence: This is completely natural and does not indicate illness.