CINCINNATI — Just call her Professor Fiona.

The Cincinnati Zoo’s famous premature baby hippo does more than delight social media fans and help sell a wide range of merchandise. She’s also an educational and literary force, heroine of a half-dozen books so far and a popular subject for library and classroom activities.

The latest book is “Saving Fiona,” (Houghton Mifflin Harcourt) written by the zoo’s director, Thane Maynard.

“She has taught us a lot,” Maynard said. It’s believed Fiona is the smallest hippo ever to survive. Born nearly two months early, she was 29 pounds, a third the size of a typical full-term Nile hippo and unable to stand or nurse.

A zoo staffer hand-milked her mother, Bibi, and Smithsonian’s National Zoo in Washington helped develop a special formula. Nurses from Cincinnati Children’s Hospital were enlisted to put in a hippo IV.

“We were a nervous wreck every day,” Maynard said of Fiona’s first six months after her birth in January 2017.

His book is aimed at young readers, telling Fiona’s against-the-odds story while loading in facts about hippos, such as that they can outrun humans and are herbivores that can be dangerous because of their size of up to 5,000 pounds.

“Part of the zoo’s mission is public education,” Maynard said. “(The book) is reaching kids and families with a message of hope … never giving up.”

The combined Fiona library of books has sold tens of thousands so far.