Which African safari animal can close its nostrils while submerged?

The hippopotamus can close its nostrils while submerged.

A hippo’s eyes, ears, and nostrils are positioned high on its head, allowing the animal to remain mostly underwater while monitoring its surroundings. Specialized muscles can close the nostrils and ears when the hippo dives, helping keep water out of these openings.

This adaptation suits a semiaquatic lifestyle. Hippopotamuses spend much of the daylight period in rivers, lakes, and pools, where water helps support their heavy bodies and reduces overheating. They usually leave the water at night to graze on grasses.

Hippos are strong swimmers in some contexts, but they are also known for walking or pushing off along the bottom rather than floating like many aquatic mammals. Their ability to close the nostrils should not be confused with breathing underwater: they must surface to breathe air.