Rosie, a 43-year-old western lowland gorilla and matriarch to the North Carolina Zoo's gorilla troop, died Thursday.
The zoo announced her death on its Facebook page, saying a cancerous mass had been discovered on Rosie's abdomen. Because of the gorilla's advanced ago, veterinarians determined any medical procedures would be too risky. So Rosie was euthanized.
"Rosie was a feisty and at times cantankerous old lady, but she was well respected by her troop members and caretakers,” said Jennifer Ireland, curator of mammals for the North Carolina Zoo.
The median life expectancy for a female gorilla is 38 ½ years old, according to the zoo.
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Rosie was born in 1974. In 2015, she and her grandson, a silverback Mosuba gorilla named Hadari, came to live in North Carolina from the Henry Doorly Zoo in Omaha, Nebraska.
Rosie had several children. She was the mother of the first and only western lowland gorilla born through in vitro fertilization, in 1995, the zoo said. She was also known as an excellent surrogate mother who cared for offspring that were not her own.
Western lowland gorillas are critically endangered because of habitat destruction and poaching.
The gorilla population has declined by more than 60 percent over the last 20 to 25 years. The International Union for Consservation of Nature estimates there are 150,000 to 250,000 of the animals living in the wild.