Helen, the oldest western lowland gorilla in the U.S., has died at the age of 64.
The Louisville Zoo in Louisville, Kentucky, announced it made the tough decision to euthanize Helen on Friday, Oct. 14, because her quality of life declined for several months due to natural aging, according to a media released by the zoo.
Helen had been in "remarkably good health for most of her life" despite being diagnosed with "expected age-related arthritis and some periodontal disease," the zoo said.
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In recent months, Helen developed instability and tremors that put her at fall risk and impacted her day-to-day life, the zoo's media release explained.
Female zoo gorillas typically have a median life expectancy of about 39 years, according to the Louisville Zoo.
Helen’s estimated birth year is 1958, and she was born in the wilderness of Western Africa, which is now modern-day Cameroon, the zoo’s release said.
She was transferred to the Louisville Zoo in 2002 after spending time at the Lincoln Park Zoo in Chicago.
In her old age, Helen had received care from a dedicated dentist, cardiologist, gynecologist, neurologist, orthopedist and pain manager, according to Dr. Zoli Gyimesi, senior veterinarian at the Louisville Zoo, who shared these details in the zoo’s media release.
Gyimesi said staff at the Louisville Zoo were able to gain in-person knowledge about gorillas and geriatric gorilla care by studying Helen.
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"Letting go of a special gorilla like Helen is very hard, but it is often the last, best thing we can do for our animals," said Dan Maloney, Louisville Zoo director, in a statement.
"Helen’s exceptional longevity is not only a testament to her personal constitution, but also to the outstanding care provided by her keeper team and the animal health care staff over these past 20 years," Maloney continued. "Helen was one of our most beloved ambassadors. Her fascination with human babies delighted families for decades. I know our friends and members will share in her loss and miss her greatly."
Zoo staff and visitors reportedly nicknamed Helen the "Grand Dame" because her long lifespan allowed her to become a mother of three, a grandmother of 17 and a great-grandmother of 21. She was also a great-great-grandmother of eight and a great-great-great-grandmother of one, according to the Louisville Zoo.
Helen’s great-grandson Bengati, 24, and her great-great-granddaughter Kindi, 6, reportedly still reside in the Louisville Zoo’s four-acre Gorilla Forest exhibit.
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Following Helen’s death, the Louisville Zoo is now home to eight gorillas, according to the zoo’s exhibit webpage.
The zoo divides the octet of great apes into two family groups, and they’re a mix of western lowland gorillas and silverback gorillas.
Casey, a male silverback gorilla who was born in 1982, is now the oldest in the Louisville Zoo’s pack.
Helen was the oldest gorilla in North America and the second-oldest gorilla in the world, according to the Louisville Zoo.
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The world’s oldest western lowland gorilla is named Fatou, and she lives in Germany at Zoo Berlin. She turned 65 in April 2022, Fox News Digital reported.