Hippopotamuses: Hippopotamidae

Hippopotamuses (often called hippos) have huge, round bodies that sit atop short legs. Males weigh 600 to 4,000 pounds (270 to 1,800 kilograms) and measure 60 to 106 inches (152 to 270 centimeters). Females weigh between 500 and 3,000 pounds (230 to 1,500 kilograms) and measure 58 to 106 inches (150 to 270 centimeters). Hippos have four toes on each foot with slight webbing between them. Though the skin looks hairless, there is a sparse covering of fine hairs over the entire body. The hippo has no sweat glands, but it does have skin glands that secrete a fluid. Experts believe this liquid acts as a sunscreen as well as an antiseptic (germ-killer). Hippos vary in color from slate brown to mud brown, and in certain lighting give off shades of purple.

The head is big with a wide mouth. The canines (pair of pointed teeth located in the front of the mouth on both jaws) and incisors (four front teeth, situated between the canines on both jaws) look like tusks and grow continuously throughout the hippo's lifetime.

The nostrils, eyes, and ears are located high on the face, which allows the animal to remain submerged for a long time with very little of its body showing. The hippo has a multi-chambered stomach, which allows for fermentation (breakdown) of food for more efficient digestion.