Monozygotic twins Mosuba and Macombo were born at the Columbus (Ohio) Zoo in 1983. During their first year, weight and skeletal growth indicators were virtually identical. The twins lived together continuously until age 7, when they were permanently separated. Mosuba joined a group of males and elderly, non-breeding females in the Henry Doorly Zoo of Omaha, Nebraska. He sired an infant by artificial insemination at age 12. At age 16, Mosuba had the appearance of a fully mature silverback, with prominent sagittal and nuchal crests and typical large body size, consistent with his age.
Bellisari, Anna and French, Jeffrey, "Hormonal Assessment of Sexual Maturation in Four Captive Lowland Gorilla Males" (2003). Psychology Faculty Publications. 121.