The Common Hippopotamus, or the River Hippopotamus, dominates the African landscape, ruling sub-Saharan Africa's lakes, rivers, and mangrove swamps. 

A male hippo can reach 3,260 lb. Despite its massive size, it is surprisingly fast, reaching up to 22 miles per hour on land on short distances. 

One of its most distinctive characteristics is the secretion of "blood sweat," which acts as a natural sunscreen and antibacterial agent. 

Male hippos reach maturity at 7.5 years old, while cows are 5 to 6 years old. After an eight-month gestation period, a female hippo isolates herself from the group. It gives birth to one calf on land or in shallow water. 

Interestingly, calves fold their ears and close their nostrils as they nurse on female hippos underwater. Moreover, this nocturnal herbivore can consume around 80 pounds of grass overnight. Adults have no known natural predators, but lions, hyenas, and crocodiles endanger young hippos.

Despite their formidable size, Common Hippos are not sociable. While they form groups, they do so primarily for protection rather than companionship.

The hippos are a vulnerable species, facing a population decline due to poaching and civil unrest1. Elephant ivory substitutes, such as hippo teeth, heighten demand in illegal markets. Conservation efforts are vital, yielding slight improvements in protected areas.

Here are five subspecies of the common hippo with differences in their skulls and geographic ranges

The Pygmy Hippopotamus is native to the dense forests and marshy swamps of West Africa. Unlike its larger relative, it is only half its height and weighs only a fraction. It measures 69 inches long and stands 39 inches tall at the shoulder. 

Moreover, the pygmy hippo lives in the water more than on land. While these animals weigh up to 606 pounds, they move with the grace and agility of a jungle ballerina.

This solitary creature spends the day hidden in cool rivers or wallows, venturing only at night to forage for food. It eats ferns, broad-leaved plants, grasses, fruits, small insects, and worms. 

Pygmy hippos are facing declining numbers due to habitat destruction from commercial plantations2, mining, and shifting agriculture. Intensified bushmeat hunting exacerbates their plight, warranting their endangered status. With fewer than 2,500 mature individuals, a 20% population decrease over two generations is projected.