DALLAS (CBSDFW.COM) – The Dallas Zoo is mourning the death of a 23-year-old gorilla, Hope, that died unexpectedly Sunday night.

The Dallas Zoo tweeted Monday night, “We are devastated to share the news that Hope, our 23-y/o western lowland gorilla, passed away suddenly last night. The family troop will remain off habitat so that staff can monitor them 24/7 for any signs of distress as they mourn this loss.”

Hope the gorilla (courtesy: Dallas Zoo)

Hope and the other members of the troop had been experiencing mild gastrointestinal symptoms recently, which animal care staff were closely monitoring and treating, the Dallas Zoo explained in a statement.

“Our veterinarians tested for parasites and other pathogens, including Salmonella, and test results came back negative,” the Zoo said.

Initial necropsy findings indicate that Hope’s colon was severely inflamed.

Additional testing is pending.

“Right now, our top priority is the well-being of the family troop, including one-and-a-half-year-old Saambili,” the Zoo said in its statement. “Keepers say that she appears understandably shaken following the death of her mother, but gorilla family bonds are strong, and the other family members have stepped in to support and comfort her. She seems to be relying most heavily on her dad, Subira, who was there to comfort her immediately and has not left her side. The family troop will remain off habitat while we continue to monitor them closely. We are all completely heartbroken by this sudden loss and ask that you please keep our staff and our gorilla family in your thoughts.”