plush toy hippopotamus, likely intended for children. Key facts about hippos include: Hippos are large, semi-aquatic mammals native to sub-Saharan Africa. They spend a significant amount of time in rivers and lakes to stay cool. Adult hippos can weigh between 2,870 and 4,000 pounds. They are herbivores, primarily eating grass. Hippos live in groups called pods. The name "hippopotamus" comes from the Greek word for "river horse". Their closest living relatives may be pigs or whales and dolphins. Hippos are currently classified as vulnerable due to habitat loss.
