When submerged underwater, hippos can hold their breath for 5 minutes or even longer if needed. Hippos have nostrils located on the top of their heads, which allows them to breathe even if the rest of their body is under water.
Hippos are also able to sleep underwater because they have a built-in reflex that causes them to bob up to the surface for air when necessary. Hippos can also see well underwater because they have a clear protective membrane over their eyes. Despite having adapted for life in aquatic environments, hippos cannot swim. They mainly live in lakes and slow moving rivers throughout the African continent.