Hippo

The hippo, or hippopotamus, refers to the two living species of large, semi-aquatic mammals in the family Hippopotamidae. The common hippo (Hippopotamus amphibius) inhabits rivers, lakes, and swamps across sub-Saharan Africa, while the pygmy hippo (Choeropsis liberiensis) occupies forests and wetlands in West Africa. Both species are herbivorous and spend much of the day in water or mud to stay cool and protect their skin.

Physically, adult hippos are among the largest land mammals, with barrel-shaped bodies, short legs, and nearly hairless skin. They weigh roughly 1,400–3,200 kg for adults of the common species, while pygmy hippos are smaller. Their mouths are wide, with tusk-like canines, and their eyes, ears, and nostrils sit high on the head, enabling breathing and sight while mostly submerged. They can hold their breath for several minutes.

Socially, hippos form groups in water, commonly called a pod, herd, or bloat, though the pygmy species tends to be more reclusive. In water, males defend territory; on land they graze at night on grasses and occasionally aquatic vegetation. They communicate with vocalizations such as grunts and wheezes and are capable of rapid, sometimes aggressive behavior when threatened.

Reproduction occurs in water; gestation lasts about eight months and typically a single calf is born underwater. Calves are competent swimmers soon after birth and may nurse while submerged. Maturity is reached in early adolescence, and lifespans exceed 40 years in the wild.

Conservation status: the IUCN lists the common hippo as Vulnerable, with populations declining due to habitat loss, poaching for meat and skins, and conflict with humans. The pygmy hippo is also threatened, though it is less numerous and more restricted in range.