The Columbus Zoo and Aquarium in Ohio recently welcomed a new baby gorilla, but the arrival of the infant came with a surprise: the baby’s mother, Sully, was previously thought to be a male.

Sully, an 8-year-old gorilla, arrived at the Columbus Zoo in 2019 from another zoo. She was initially identified as a male due to her physical appearance, which is similar in young gorillas of both sexes. Males develop more pronounced features, such as a larger size, silver back, and head bump, later in life.

Sully’s birth zoo adopted a “hands-off” approach to raising their gorillas, which meant that no medical intervention was conducted. This could have led to an early discovery of Sully’s actual gender, but there were no concerns about her health, so no check-ups were needed.

Sully’s pregnancy was also a surprise. Gorillas’ pregnancies are rarely noticeable, as the babies are insignificant compared to human infants. Sully’s baby is estimated to have been conceived last fall.

The birth of this baby gorilla is a welcome addition to the Columbus Zoo and a significant contribution to the conservation of endangered Western lowland gorillas. The zoo is committed to nurturing their inhabitants and fostering an environment that endorses the survival and propagation of this imperiled species.