Sub-Saharan Africa is the home to the second heaviest land mammal in the world — the hippopotamus. Their dense bodies make it impossible for them to swim, even though they spend most of their time in the water. The body of the hippopotamus is well suited for aquatic life. Their eyes, ears and nostrils are located at the top of their head, so they can see, hear, and breathe while mostly submerged.
A clear membrane covers and protects their eyes while allowing them to see underwater. Their nostrils close to keep water out, and they can hold their breath for several minutes. Though they feed on land, hippos do many other activities in the water, including mating and birthing. Groups of 10-30 hippos live together with one dominant male.
During the dry season, the dominant male chooses a partner, and then the other males fight each other for the remaining females.
Eight months after conception, at the height of the wet season, female hippos give birth to one calf at a time, either on land or underwater. Afterwards, mothers leave the herd for a short period to bond with their calves underwater. After a few weeks, the calves finally exit the water to feed on grass.