Zookeepers are shocked as 'male' gorilla gives birth: 'Talk about a surprise twist'

The Columbus Zoo and Aquarium is over the moon after welcoming a new member to their gorilla family, but the good news came with an unexpected twist. Zookeepers were shocked when Sully, a gorilla they thought was male since her arrival in 2019, gave birth to a baby girl on July 20. It wasn’t until they saw Sully cradling her newborn that they realized their mistake.

"We have an adorable surprise to share with all of you today! Our gorilla family just got a little bigger with the unexpected birth of a female baby gorilla! But here's the other incredible part: our dedicated keepers recently discovered that the proud mom, who was initially believed to be a male, is actually a female gorilla. Talk about a surprise twist!" the zoo announced in a post on Facebook.

The post further read, "This exciting event shines a spotlight on the importance of preserving these magnificent creatures and their habitats. According to the International Union For Conservation of Nature Red List of Threatened Species, western lowland gorillas are critically endangered in the wild due to deforestation, habitat loss, and the devastating illegal bushmeat trade."

Many people on the internet seemed confused as to how the zoo couldn't find out the actual sex of Sully. "I hate to say this, but what kind of zoo are you where you had this gorilla since 2019 and didn't know its sex?" one person asked. Another questioned, "So you’re saying the newborn baby is a female? Are you sure?"

In their blog, the zoo addressed the comments and explained, "It’s hard to tell the sex of younger gorillas. Until about age 8, males and females are about the same size, and they don’t have prominent sex organs. As gorillas age, they become sexually dimorphic, meaning males and females look very different. However, males don’t develop their characteristic large size, silver backs, and large head bumps (called sagittal crests) until age 12 or later." They further elaborated that the previous zoo had a "hands-off approach" to Sully's care when she was born. "While Sully was initially identified as male, upon arriving at the Columbus Zoo, Sully was a young and healthy animal and did not need any procedures requiring immobilization that would have led to this discovery sooner," they said.

Usually, female gorillas reach sexual maturity between 8 to 10 years of age and have large and distended bellies, which also makes pregnancy difficult to determine. The zoo plans on performing a DNA test to determine her baby's father.

Sully's baby has become the 34th gorilla born at the wildlife facility. "Now that Sully and her baby have had some time to bond with one another and other members of their troop, we are proud to invite gorilla fans to officially celebrate the baby's birth by visiting the indoor gorilla habitat," shared the zoo. 

Editor's note: This article was originally published on August 11, 2023. It has since been updated.