Hippopotamuses are large, semi-aquatic mammals primarily found in the rivers, lakes, and swamps of sub-Saharan Africa. These creatures are recognized for their bulky bodies, stout legs, and massive heads. Despite their common name, which translates to “river horse” from Greek, hippos are not related to horses; their closest living relatives are surprisingly pigs and cetaceans like whales and dolphins. They spend a significant portion of their daylight hours submerged in water, a behavior central to their survival and adaptations.
Hippo Movement in Water
Hippos do not truly swim in the conventional sense. Their bodies are exceptionally dense, causing them to sink rather than float. Instead of swimming, hippos move by pushing off the bottom of the riverbed with their powerful legs.
This movement is often described as walking, running, or even galloping underwater. In shallower areas, they simply walk along the bottom, while in deeper sections, they can push off and perform porpoise-like leaps to move forward. Their ability to regulate buoyancy by controlling their breath allows them to sink or rise as needed. Hippos typically surface every three to five minutes to breathe, pushing themselves up from the riverbed before sinking back down.
Assessing Their Aquatic Speed
Despite their immense size, hippos are agile in their aquatic environment. Underwater, they can reach speeds of up to 5 miles per hour (8 kilometers per hour). This speed is achieved by galloping or leaping along the riverbed.
This movement allows them to navigate their aquatic habitats with remarkable efficiency. Hippos are considerably faster on land, capable of short bursts of speed up to 19 to 28 miles per hour (30 to 45 kilometers per hour). This combination of underwater quickness and land speed makes them effective inhabitants of their territories.
Why Water is Essential for Hippos
Water plays a fundamental role in the life of a hippopotamus, providing several benefits beyond facilitating movement. Hippos spend most of their day submerged to regulate body temperature and avoid overheating in the intense African sun. Their skin is particularly sensitive and thin, making it vulnerable to dehydration and sunburn if exposed to the sun for extended periods.
To protect their delicate skin, hippos secrete a reddish-orange substance, sometimes referred to as “blood sweat,” which functions as a natural sunscreen and possesses antibacterial properties. This secretion helps shield them from harmful ultraviolet rays and keeps their skin moist. The buoyancy provided by water supports their massive weight, reducing stress on their joints. Water also serves as a refuge, offering safety from land predators and a secure environment for their young.