CINCINNATI -- You can breathe a little easier; not-so-little Fiona was taken off supplemental oxygen late last week, Cincinnati Zoo officials said.
Fiona’s lungs are almost fully developed as she has been learning to dive and hold her breath in the pool, Cincinnati Zoo hippo handler Wendy Rice said in an official zoo blog post. The zoo's veterinary staff have been monitoring the levels in her blood to ensure she is progressing.
Fiona had been on oxygen since she was 8 days old. Lungs are often the last organ to develop in premature mammals, Rice said.
Rice said Fiona now shows normal dive responses, and she can dip her face below the water for up to 20 seconds. Fiona's health has been steadily improving, and keepers are looking forward to introducing her to her parents, Bibi and Henry, in the coming weeks.
Hippopotamus babies are typically born underwater, which allows them to learn to hold their breath. Mother hippos spend most of their time in water, so newborns must learn to dive, nurse and resurface for air every 30 seconds.
For Fiona, though, this diving instinct was extremely dangerous.
She would close her eyes and nostrils to the point where zoo keepers could see the skin around her eyes and mouth turn white. Rice said at just one week old, Fiona would hold her breath for up to 75 seconds -- more than double the amount observed in full-term baby hippos.
At eight weeks, Fiona began wearing a cannula when she was napping or resting. Rice said the zoo's veterinary staff noticed a difference in her breathing almost immediately.
Fiona will eventually be able to hold her breath underwater for two to three minutes as a juvenile. She will be able to hold her breath for up to five minutes once she reaches adulthood.