Veterinarian Nadine Lamberski worked with the baby all weekend. She said Monday that the gorilla probably contracted the pneumonia during Friday's birth, when a surgical team also had to fix a collapsed lung.
The mother gorilla, an 18-year-old named Imani, had never given birth. The zoo says the C-section, rare for a gorilla, was performed because she was in distress after going into labor.
The medical team included vets and two doctors who usually work on humans: a neonatal specialist and an anesthesiologist.