* They breathe air: Hippos are mammals, and like all mammals, they need to breathe air. They can hold their breath for a short time, but they must come to the surface regularly.
* They give birth on land: Unlike aquatic animals like dolphins or whales, hippos give birth on land.
* They are primarily terrestrial: Although they love to cool off and socialize in water, they spend the majority of their time on land, feeding, sleeping, and raising their young.
So, while hippos are semi-aquatic, they are not fully aquatic animals.