Kumba, who made history in 1970 as the city’s first captive-born gorilla, was euthanized Saturday by keepers at Lincoln Park Zoo after years of slow deterioration caused by kidney failure.
The shy and mostly quiet gorilla was a cornerstone of sorts for the zoo’s reputation as a successful breeding facility. In the 1930s and ’40s Lincoln Park had become world famous because of a single animal, Bushman, a huge lowland gorilla voted by zoo directors as the greatest zoo attraction in the world. After his death, Lincoln Park wanted to continue his legacy by becoming a breeding center.
The zoo brought in eight young “founder” gorillas from the wild for that purpose in the 1950s and ’60s. Kumba was the first baby to be born from that effort. Since then, the zoo has become one of the top gorilla breeding facilities in the world, with 45 births.
“Losing an animal is the most difficult part of working at the zoo, and it was really tough to say goodbye to Kumba,” said Robyn Barbiers, the zoo’s general curator.
“For the past few years, we have been closely watching Kumba because of her reduced renal [kidney] function, and we have administered a variety of treatments, but her condition continued to deteriorate,” she said. “It became evident that she was dying.”
Kumba would have turned 35 in July. Since November, Barbiers said, her health had been in a tailspin as she lost weight and became lethargic. Her system had stopped metabolizing foods, and she had lost interest in eating.
On Saturday zoo veterinarians and ape-house keepers anesthetized her for another round of tests with a prior agreement that, if her condition showed no hope of improvement, they would euthanize Kumba to stop her suffering.
Dan Wharton, director of New York’s Central Park Zoo and head of the lowland gorilla species survival plan that oversees captive breeding programs in the U.S., said old age for gorillas seems to start at about 30.
“As a rough way of looking at it, we double a gorilla’s age to get to an equivalent human age,” he said, “so a 35-year-old gorilla is akin to a 70-year-old human, making Kumba not young, but not so old, either.
“In animals in general, renal failure is generally what kills you in old age when nothing else, like injury or infection, gets you first. The kidney is just the organ that often fails you at an advanced age.”
In fact, Kumba’s mother, Mumbi, died of renal failure at age 37, as did other females from the zoo’s founding gorilla breeding group, all in their late 30s and early 40s.
Zoos no longer need to bring gorillas in from the wild. When Kumba was born, however, zookeepers still were struggling to figure out the variables that led to successful breeding.
Gorillas had been in zoos for more than 100 years before the first was born in a zoo in 1956. Most wild-caught gorillas died young until zoos figured out their overall nutritional needs.
“Then zoos had to figure out the basic aspects of gorilla society,” said Don Winstel, an assistant zoo director at the Columbus, Ohio, zoo where the first zoo gorilla, Colo, 49, was born.
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From field researchers in Africa such as Dian Fossey, zoos learned gorilla families were made up of multiple females and a single dominant male. Once zoos started putting their own gorillas in that family configuration, the birthrate exploded.
Kumba was a member of the female gorilla harems of several different males over the years. She was always a relatively solitary animal, however.
She had one baby, Kowali, a female now 27 and still at the zoo, who in turn has had two daughters: Rollie, 8, and Mumbali, 7, also living at Lincoln Park.
The last family Kumba lived with, headed by a young male, Kwan, was the first to move into the new great ape house last year. In the old, underground ape house, she seldom showed interest in going outdoors.
“I think she learned to like the outdoors in the new building,” said Sue Margulis, the zoo’s primate curator who came from Brookfield Zoo in October.
“On warmer winter days we let them go out, and she always was eager to do that when we opened the doors, especially if there was snow on the ground,” she said. “She liked to grab a handful and eat it, like a treat.”