In this Dec. 22, 2015 file photo, Colo sits in her enclosure during her 59th birthday party at the Columbus Zoo and Aquarium in Powell, Ohio. The oldest known gorilla living in a zoo, a female named Colo, is slated to undergo a surgical biopsy sometime soon ahead of her 60th birthday on Dec. 22, 2016. The Columbus Zoo and Aquarium in Ohio says veterinarians have been monitoring a mass under Colo's arm that recently started causing her discomfort, so they want to take tissue samples to determine the cause and possible treatment. She'll also be getting a thorough medical check-up.(Tom Dodge/The Columbus Dispatch via AP)
The oldest known gorilla living in a zoo is doing well after a surgical biopsy ahead of her 60th birthday on Dec. 22.
The Columbus Zoo and Aquarium said Saturday that veterinarians successfully removed a mass under the gorilla's arm that recently started causing her discomfort.
The zoo also took tissue samples from the gorilla, a female named Colo, to determine the cause and possible treatment. She also got a thorough medical check-up.
Colo will remain off-exhibit while she is observed after the surgery.
Colo was the first gorilla born in a zoo. She has surpassed the usual life expectancy by two decades.
Colo is a mother of three, grandmother of 16, great-grandmother of 12 and great-great-grandmother of three.
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