How exactly have these notoriously aggessive animals evolved to function under the water?
We explore how these massive mammals function and thrive beneath the surface.
Can hippos breathe underwater?
As mammals, hippos have lungs just like we do. Lungs aren’t much use under water, to the point being a liability. Water is dense and viscous, so it takes a lot of effort to pump it in and out of internal inflatable bags. Too much effort, in fact – hence drowning.
Lungs are only good for breathing air, which is what hippos and other aquatic mammals such as whales, seals and manatees must do.
That said, hippos can breathe air while being almost entirely submerged, thanks to high-set nostrils that protrude out of the water. These can be sealed when the animals need to dive.
How long can hippos hold their breath?
They can last about five minutes between breaths, which is not particularly long compared to other aquatic mammals (an elephant seal can last two hours). It’s long enough, though, for an animal that lives in shallow rivers rather than the ocean depths, where it is never far from a fresh lungful of air.
Do hippos sleep underwater?
Hippos are also capable of sleeping underwater and observations suggest that they can float to the surface for air and then sink down again – without waking up.
Find out more
Check out our comprehensive guide to hippos, as well as other features, including hippos: ecosystem engineers and how the ivory ban now extends to hippos.