The Dallas Zoo announced Monday that Hope, a 23-year-old Western Lowland Gorilla passed away suddenly Sunday night.
Dallas Zoo officials said Hope and other members of the gorilla troop had recently been experiencing mild gastrointestinal symptoms. Animal care staff had been closely monitoring and treating the symptoms. The Dallas Zoo veterinarians tested for parasites and other pathogens, including Salmonella, and test results came back negative.
Zoo officials said initial necropsy findings indicate that Hope's colon was severely inflamed. Additional testing is pending and will hopefully give the zoo more information about what could have caused the death.
"For us to have an animal who appeared a little bit off the night before and passes away suddenly overnight is a shock to the system. said Harrison Edell, the zoo's executive vice president of animal care and conservation. "It's frustrating. We want to understand why and how that happened."
He added the current focus was to make sure there wasn't a viral cause for Hope's death.
Zoologists are monitoring the troop, including 18-month-old Saambili, who is Hope's child.
Edell said while Saambili will take food and liquids from zookeepers, the goal is not for them to hand rear her. Instead, they're hoping the other females in the troop will take over raising her until she's fully matured. Edell says that generally happens by the age of three.
He said Saambili's father, Silverback Subira, was the first to approach the gorilla after her mother's death.
He said the females in the troop have interacted well with her, too.
The gorillas will remain off-habitat while zoo officials to monitor their progress.
The last gorilla to die at Dallas Zoo was Madge who passed in March 2016 at 34 years old.
According to Edell, most gorillas live to their mid or late 30s.