Hippos are a semi-aquatic mammal, usually inhabiting shallow lakes, rivers, and swamps. Indeed, the name hippopotamus is derived from a Greek word meaning ‘river horse’ due to its semi-aquatic lifestyle. Hippos, the third largest known mammal, share with whales a tendency to be aquatic. This has been shown in a recent research to be more than mere coincidence as the two mammal’s genetic similarities and common ancestry has been established although Hippopotamus shares with hog and pig members of the artiodactyla order, a very thick, naked skin, a thick and square head, a very large muzzle, small eyes and ears, thick and heavy body and short legs. Scientists believe marine mammals such as whales may have evolved from Hippos some 52.5 million years ago, apparently because these early terrestrial ancestors of these groups began feeding in the water and became more adapted to aquatic conditions over time. Yoruba call it Erinmilokun or Erin-odó, meaning, “elephant of the water.”
Weighing between 1,300 and 3,200 kg, hippopotamus measure between 209 and 505 cm in length, including a tail of about 35 cm in length. They stand between 150 and 165 cm tall. Hippopotamuses live in groups of 15 or more animals. These groups are primarily females and their young headed up by a dominant male. With the long, razor-sharp incisors and tusklike canines, the hippo is well-armed and dangerous. The diet is exclusively vegetarian, consisting of plants, grasses, tender shoots, leaves and fallen fruit. At night, these herbivores leave the water, venturing into the forest in search of plants and fruits to eat. They establish trails in the forest to ease movement, marking their territory with feces. Hippos lack scent and sweat glands. Instead, mucous glands secrete a thick oily layer of red-pigmented fluid, mistaken for blood by some. Average gestation period is 243 days and lifespan reaches 55 years in captivity.
The Nigerian subspecies of the common hippopotamus, tschadensis, is hardly different from other subspecies in Africa. As few as 400 hippos exist in both Nigeria and Niger combined. A larger fraction of this is found in Yankari and Kaniji national parks. The Adamawa state of Nigeria Wildlife Control agency usually stage awareness campaigns, teaching people in river communities about hippopotamuses’ routines so that they can avoid them.