Kibibi, who still lives at the zoo, was the last gorilla born there, in January 2009.
The pregnancy is considered a big deal at the zoo because western lowland gorillas are critically endangered in the wild. Over the past 25 years, their population has dropped by 60 percent.
With the baby gorilla coming in the spring, the facility will have two primate infants. The zoo also has Redd, a 1-year-old Bornean orangutan.
“It is a rare and exciting event that we will soon have not one, but two, primate infants at the Great Ape House,” said Meredith Bastian, curator of primates, in a statement.
Calaya came to the zoo in February 2015 from the Woodland Park Zoo in Seattle. When she arrived, she was “aloof and disinterested,” zookeepers said. She would “avoid eye contact, grunt and walk away whenever they tried to engage with her,” zoo officials said.
But she gradually got along with her troop. Zookeepers also discovered that she liked to watch other gorillas do training exercises and then repeat their actions. She’s been trained to urinate on cue for hormone analysis and allow body exams.
Eventually, she and a 25-year-old male silverback named Baraka showed interest in each other, zookeepers said, and they bred in the summer. Zookeepers did a pregnancy test — similar to one done for humans — and confirmed that she had conceived.
Zoo officials warned in a statement that “as with any animal pregnancy, there is a possibility that miscarriage, stillbirth or a complication could occur.”
Calaya is one of six gorillas at the zoo, and this is her first pregnancy.
The zoo said it plans to provide weekly updates on her pregnancy on social media, using the hashtag #GorillaStory.
Keepers have also trained Calaya on her future motherhood duties by showing her photos of mother gorillas holding and nursing infants. And she’s been taught how to “touch, kiss and nurse” a stuffed gorilla toy. All of the training, zookeepers said, “enhances the likelihood that Calaya, who will be a first-time mother, will care for her infant.”
Western lowland gorillas like Calaya have become critically endangered, zoo experts said, because they face diseases and poaching. There are estimated to be roughly 150,000 to 200,000 western lowland gorillas in the wild in parts of central Africa.