AVONDALE, OH (FOX19) - Fiona is now napping underwater!
According to the Cincinnati Zoo & Botanical Garden, hippos can sleep underwater and automatically raise their nostrils above the surface for a breath- without even waking up.
Adult hippos can hold their breath for several minutes, but Fiona comes up for air about every 15 seconds.
The zoo said that as she grows larger, her lung capacity will increase as well.
At last check, Fiona was tipping the scales at more then 90 lbs.
The Nile hippo weighed just 29 lbs. when she was born in January.