Officials at Chicago's Shedd Aquarium announced Tuesday that Rio, a 21-year-old North American river otter, had been euthanized.
In a statement, Ken Ramirez, the aquarium's executive vice president of animal care and training said Rio was put down because of progressively deteriorating health and quality of life issues associated with her old age.
At 21, she had exceeded the known median life expectancy of river otters by nearly a decade, he said.
"It’s been a remarkable experience watching Rio inspire our guests throughout her years at the aquarium," said Ramirez. "With her playful personality, Rio was a beloved ambassador for her species."
Rio, whose name means "river" came to the Shedd in 1992 from the Little Rock Zoo in Arkansas.
A sea otter named Kachemak, who was considered the oldest sea otter living in any North American zoo or aquarium, was euthanized in August.
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