The hippopotamus is a semi-aquatic mammal known for its large size and unique behavior. They spend most of their day submerged in water to keep cool, emerging at night to graze on grasses. Despite their bulky appearance, hippos can run surprisingly fast on land, reaching speeds of up to 19 miles per hour. Hippopotamuses are social animals, often found in groups called pods, which can consist of 10 to 30 individuals. They communicate through a variety of vocalizations, including grunts and wheezes. Territorial males will defend their space in the water, while females are more nurturing, caring for their young in a protective manner.