The hippopotamus kills more people in Africa than lions and crocodiles combined — and it isn’t even a predator. This massive, mostly herbivorous giant is fiercely territorial, surprisingly fast on land, and covered in a strange reddish secretion once mistaken for sweating blood. Few animals on the safari circuit are as common, as photogenic, or as genuinely dangerous. Explore our Tanzania safaris for the best river and boat safari itineraries.
Key Highlights
- Responsible for more human deaths in Africa each year than lions or crocodiles
- The third-largest land mammal, with bulls weighing up to several tonnes
- Secretes a reddish fluid that acts as sunscreen and antibiotic, once mistaken for “blood sweat”
- Bulls defend river and lakeshore territories, sometimes fighting in the shallows
- The Rufiji River holds one of the largest hippo populations in Africa outside the Nile system
- Boat safaris offer the closest, most detailed hippo viewing available on safari
Africa’s Most Dangerous Large Mammal
The common hippopotamus (Hippopotamus amphibius) is the third-largest land mammal on Earth, with bulls sometimes weighing several tonnes. Despite being mostly herbivorous, it’s responsible for more human deaths across Africa each year than lions or Nile crocodiles — mostly the result of encounters on land at night, when hippos leave the water to graze and can react aggressively if surprised or if a person gets between them and their route back to the water.
That reputation for danger sits alongside a very different reality on safari: hippos are also one of the most common and reliably seen large animals across the region. The Mara River holds thousands during the dry season, when surrounding water sources dry up and hippos concentrate into the remaining permanent pools. The Rufiji River in Tanzania’s Nyerere National Park supports one of the largest hippo populations anywhere in Africa outside the Nile system, and even Ngorongoro Crater has its own small resident population in the central soda lake’s freshwater seep.
The Truth About “Blood Sweat”
One of the hippo’s strangest features is the reddish, oily fluid that appears on its skin soon after it leaves the water. Early European observers, understandably confused, called it “blood sweat,” and the description stuck for well over a century before the chemistry was properly worked out. It’s neither blood nor sweat — it’s a specialised skin secretion unique to hippos, doing two jobs at once.
One component acts as a natural sunscreen, absorbing ultraviolet light that would otherwise damage the hippo’s nearly hairless, unpigmented skin during long hours basking on riverbanks. Another component works as an antibiotic, helping to protect the frequent wounds hippos pick up during the regular fighting that comes with defending territory. Together, these compounds let a hippo spend most of the day out of the water in intense equatorial sun without the sunburn or skin infections that would otherwise be inevitable.
Territory, Combat, and the Jaw-Gape Display
Adult male hippos defend stretches of river or lakeshore as territory, protecting a pod of females and their young from rival bulls. Rather than jumping straight to physical combat, most disputes are settled through an intimidating display: the bull opens its jaw to an extraordinary angle, showing off the long lower canines it develops from a young age. This alone is usually enough to make a challenger back down.
When it isn’t, fights happen mostly in the shallows, where both animals can brace their hind legs against the riverbed while swinging their heads and canines at each other above the surface. These clashes can run for a surprisingly long time before one hippo disengages, submerges, and swims off in defeat. Territorial disputes become noticeably more common during the dry season, when shrinking water forces hippo pods into closer contact and territories get squeezed into a smaller stretch of river.
Where to See Hippos on Safari
The Mara River offers some of the most reliable hippo viewing anywhere in East Africa, with dense pools easily spotted from a standard game drive. The Seronera River in the Serengeti has its own resident pods, and Ngorongoro Crater’s small hippo population makes for a striking photo alongside the pink hues of the crater’s soda lake.
For the closest and most detailed encounters, a boat safari on the Rufiji River in Nyerere National Park is hard to beat. Approaching hippo pods from water level, rather than from an elevated vehicle, causes far less disturbance and allows extended, close observation of natural behaviour that’s simply not possible from land.
Frequently Asked Questions
Why is the hippopotamus considered so dangerous?
Hippos are responsible for more human deaths in Africa each year than lions or crocodiles, mostly from encounters on land at night when a person unknowingly gets between a hippo and the water.
Does a hippo really sweat blood?
No. The reddish fluid on a hippo’s skin is a specialised secretion that acts as sunscreen and antibiotic, not actual blood or sweat.
Where is the best place to see hippos in East Africa?
The Mara River and the Rufiji River in Nyerere National Park both offer excellent hippo viewing, with the Rufiji supporting one of the largest hippo populations in Africa outside the Nile system.
Is a boat safari a good way to see hippos?
Yes. A boat safari allows a much closer, water-level approach to hippo pods than a land vehicle, offering more detailed and less disruptive viewing.
Plan Your Safari
Our safari specialists can arrange a Mara River game drive circuit or a Rufiji River boat safari for outstanding hippo viewing.
Contact us today for a free, no-obligation quote on your safari.
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