Ripe old age
Colo, the world's oldest gorilla, celebrates her 60th birthday on December 22, 2016, at the Columbus Zoo and Aquarium in Columbus, Ohio.
December 22, 1956: Colo, a western lowlands gorilla, was born at the Columbus Zoo and Aquarium, becoming the first gorilla in the world born in captivity. She was tiny — weighing only 3.75 pounds (1.7 kilograms) and measuring 15 inches (38 centimeters) long.
A precious life
Colo was born earlier than expected, and Columbus Zoo staff found her shortly after birth, abandoned by her mother on the floor of their enclosure, and still in her amniotic sac. She was raised by human caregivers, who attended her around the clock.
A meager beginning
Colo's name was derived from a combination of the words "Columbus" and "Ohio." She was briefly called Cuddles, until the zoo hosted a contest to officially name her.
Gorillas are gentle and intelligent animals who live in small family groups with one adult male. Young gorillas are dependent on their mothers for the first three years of their lives.
Colo's parents were Millie and Mac, two gorillas captured in French Cameroon, Africa. They became residents at the Columbus Zoo and Aquarium during a brutal snowstorm in 1951.
Prior to Colo's birth, zoo gorillas were typically captured in the wild as babies. Often, their family members were killed in the process.
Trial by fire
Colo's birth proved that gorillas were able reproduce in captivity. Much was learned about gorilla pregnancies — notably that the gorilla gestation period is about 250 days.
Colo was rejected by her mother at birth, but 24-hour care from staff at the zoo ensured that she was healthy and socialized.
The Columbus Zoo maintains several gorilla social groupings. While Colo is content to observe other gorillas from a distance, she prefers to live apart from them, according to her caregivers.
Colo was raised in a nursery and reared by zookeepers, and introduced into the zoo's primate enclosure as she neared maturity. Since 1955, the gorilla habitat at the Columbus Zoo has changed to become more like the gorillas' natural habitat in the wild.