Donna, believed to be the world's oldest hippo, has died at the age of 62 after living more than two decades beyond the massive mammal's usual life expectancy, zoo officials said.
Donna had lived most of her life in the small town of Evansville, Indiana at the Mesker Park Zoo & Botanic Garden.
"It is with great sadness for us to announce that Donna, the world's oldest living Nile hippopotamus in captivity, was humanly euthanized this morning due to her declining quality of life caused by her debilitating severe arthritis," zoo director Amos Morris said in a statement Wednesday.
Donna was born at what is now the Memphis Zoo in 1951 and arrived at Mesker Park on August 7, 1956.
She had eight offspring with her mate Kley and had lived at the zoo longer than any of the current staff have worked there.
Hippos typically live no more than 40 years in the wild and about 50 years in captivity.
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