Columbus Zoo's 'male' gorilla turns out to be a mom

COLUMBUS, Ohio (WSYX) — Staff at the Columbus Zoo came into a big surprise when a gorilla previously believed to be a male gave birth.

A tweet from the zoo announced the new, small addition to the family.

Zoo workers found Sully holding the newborn, completely surprised.

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," a zoo statement said. "Gorillas [also] rarely show outward signs of pregnancy because the newborns are smaller than human babies and gorillas naturally have large abdomens.

Veterinarians at the zoo are maintaining a "hands-off approach" to the baby gorilla's care, as the baby seems healthy.

Zoo workers do not yet know which male gorilla at the zoo is the father. A DNA test will be conducted soon, the zoo said.

The baby has not yet been named.