Zoo officials in Ohio were in for quite the shock when a gorilla, who they thought was a male, gave birth.

Sully, who has lived at the zoo since 2019, was believed to be a boy up until Thursday when zookeepers saw the ape holding her newborn baby, the Columbus Zoo announced in a press release.

The eight-year-old gorilla fell pregnant back in the Fall, zookeepers believe, and the new mom is taking good care of her newborn girl.

“We’re thrilled by the addition of another birth for this critically endangered species. As the 34th gorilla born here since 1956 when the Columbus Zoo became the first zoo in the world to welcome the birth of a baby gorilla, she’s an important part of our work to conserve these magnificent animals,” the zoo said in a statement.

Employees are giving the pair “time to bond” before conducting a wellness exam.

Zookeepers do not know who the father is, but DNA tests will be run, the Columbus Zoo said.

Zoo officials were shocked to find the newborn, as gorillas do not show outward signs of pregnancy and Sully had never required medical care that used immobilization, which would had led to employers discovering her sex earlier.

In addition, young gorillas look the same, with males only developing their bigger size, silver backs, and head bumps around the age of 12.

In December 1956, the Columbus Zoo was the first zoo in the world to welcome a baby gorilla. For the last nearly 70 years, the zoo has “continued to make vital contributions to gorilla conservation.”

The Columbus Zoo is known for being a pioneer in “gorilla fostering for more than 30 years.”

“Over the years, nine gorillas born at the Columbus Zoo have been raised through this fostering program and seven others have been sent from other zoos to receive care,” it said in a statement.