When most people think of Tsavo, their minds go straight to elephants. But within its rivers and springs lives another heavyweight of the African wild—the hippopotamus.
At places like Mzima Springs in Tsavo West, the clear waters offer researchers and visitors a rare chance to observe hippos up close. What they reveal is a creature that is as fascinating as it is formidable.
In this week’s article, we answer some of the most frequently asked questions about these enormous semi-aquatic mammals—and explain why protecting hippos and their habitats is an important part of Tsavo’s broader conservation mission.
How Much Does a Hippo Weigh?
An adult male hippopotamus typically weighs between 1,600 and 3,200 kilograms. Females are slightly smaller, generally weighing between 650 and 2,300 kilograms. Even at birth, a hippo calf can weigh as much as 45 kilograms—about the same as a fully grown Labrador Retriever.
The largest hippopotamus ever recorded weighed nearly 10,000 pounds (4,535 kg). It was a captive individual in Germany.
What Is a Hippo’s Closest Relative?
Surprisingly, hippos are most closely related to whales, dolphins, and porpoises—collectively known as cetaceans. They share a common ancestor, a semi-aquatic mammal known as an anthracothere. These two groups diverged from this ancestor around 55 million years ago.
Are Hippos and Crocodiles Enemies?
Hippos and crocodiles often share the same waterways, and their relationship is largely one of mutual tolerance. Adult hippos are highly territorial and can be aggressive toward crocodiles, especially when calves are present. There have even been documented cases of hippos killing crocodiles—clearly asserting who dominates the river.
That said, crocodiles tend to avoid live hippos. However, if a hippo dies, crocodiles will scavenge the carcass, as seen in this photo taken along the Tsavo River.
What Do Hippos Eat?
Hippos are strict herbivores, feeding primarily on short grasses. At night, they leave the water and may travel up to 10 kilometres to graze, consuming around 40 kilograms of vegetation in a single outing.
Their muscular lips, which can be up to 50 centimetres wide, allow them to graze broad swathes of grass efficiently and harvest large quantities of vegetation quickly.
Interestingly, the pygmy hippo—found in the forests and swamps of West Africa—adopts nearly the opposite routine. It spends the day resting on land in dense undergrowth, holes, or wallows, and emerges at night to feed on aquatic plants.
Are Hippos Dangerous?
Yes. Hippos are widely considered one of Africa’s most dangerous animals. Their large size, territorial instincts, and powerful jaws make them a serious threat to both people and wildlife. They are especially aggressive in water, where they feel most secure.
Many fatal encounters occur near rivers, as people come to wash themselves or their clothes. If someone stands between a hippo and the safety of the water, the animal may feel threatened and choose to attack.
Are Hippos Nocturnal?
Hippos are primarily nocturnal grazers. During the day, they rest in rivers and lakes to stay cool and avoid sunburn. After sunset, they emerge to feed.
Hippos have a very thin epidermis which makes them vulnerable to the heat of the sun, and a hippo out of water during the day risks rapid dehydration and overheating. As a result, they spend the day submerged. They also possess no scent or sweat glands, but mucous glands secrete a viscous red fluid that dries like lacquer and serves to protect the thin epidermis against water loss, sunburn, and infection.
Remarkably, while sleeping in the water, hippos subconsciously rise to the surface to breathe, then submerge again—all without waking.
Where Do Hippos Live?
Hippos inhabit rivers, lakes, and wetlands throughout sub-Saharan Africa. In the Tsavo Conservation Area, they are most commonly seen in the Galana River and Mzima Springs, where crystal-clear waters offer a rare window into their underwater world.
How Long Can a Hippo Hold Its Breath?
An adult hippo can hold its breath underwater for around 3 to 5 minutes. Calves, being smaller and less buoyant, typically resurface every 20 to 40 seconds.
Do Hippos Have Predators?
Hippos are largely immune to predators due to their enormous size. However, baby hippos are vulnerable and would be easy prey for lions, hyenas, or crocodiles if not fiercely protected by their mothers. Mother hippos are extremely aggressive and protective of their young.
A hippo’s jaws are wide and powerful enough to bite a three-metre crocodile in half. One bull hippo that was attacked by three famished lions reportedly dragged and carried them until reaching the river, where he submerged himself, little the worse for wear, leaving the lions to swim back to shore. Nevertheless, lions are capable of killing a full-grown hippo if they can bring it down on its back, with its throat and chest exposed to their jaws.
Why Hippos Matter in Tsavo
Hippos are considered keystone species—animals that play an outsized role in shaping their ecosystems. Their grazing patterns influence vegetation near water sources, and their dung helps fertilise aquatic systems, benefiting fish and plant life alike.
In Tsavo, where water is a critical and limited resource, hippos are an integral part of the riverine landscape.
Tsavo Trust’s Role in Supporting Hippo Habitats
While Tsavo Trust is best known for protecting elephants, rhinos, and large carnivores, our commitment to landscape-level conservation supports all wildlife—including hippos.
Through projects like sand dam construction, regular patrols and support for community conservancies like Kamungi, we help protect and preserve the freshwater systems hippos rely on. These efforts are especially crucial during droughts or in areas experiencing increased human-wildlife conflict.
By protecting entire ecosystems, we protect every species that depends on them—from Super Tuskers to hippos.
Final words
Understanding hippos helps us protect them. And in a dynamic landscape like Tsavo, every species matters.
If you’ve ever watched a hippo surface silently at Mzima Springs or seen their trails winding through the bush at dawn, you know they are as iconic as they are essential.
At Tsavo Trust, we are proud to play a role in safeguarding their future—just as we do for all of Tsavo’s wildlife.
Want to support our work? Visit the Support page on our website to find out how you can get involved.