Chester Zoo has announced the sudden death of one of its five elephants.
The adult female, named Sundara Hi Way, fell ill on Friday with twisted intestines, a complication the zoo said can occur in several mammals.
The 20-year-old died despite the efforts of vet teams who had rushed to help.
“We are all so deeply shocked and saddened,” the zoo’s chief executive Jamie Christon said.
“Our thoughts are, of course, with our wonderful elephant conservationists who have cared for Sundara since she was born here in 2004,” he said.
Sundara had given birth to three calves.
Mr Christon said the mother, who was inside the zoo’s Elephants of the Asian Forest habitat when she fell ill, had “played a vital role in the conservation breeding programme for this endangered species”.
A zoo spokesperson said the illness can onset very quickly and is almost impossible to diagnose or treat in elephants.
Mr Christon said Asian elephants Riva, Indali, Anjan and Maya “remain in good health” and their teams would be monitoring them all extra closely “as the herd dynamics adjust to this sudden change”.
Asian elephants are an endangered species left vulnerable by habitat loss, poaching, human-wildlife conflict and a deadly herpes virus called elephant endotheliotropic herpesvirus.
Chester Zoo has a long history of working with the animals, both within the zoo through its successful conservation breeding programme and also in the wild.
The zoo’s Assam Haathi Project works with dozens of villages in northern India to help successfully mitigate human-elephant conflict and help protect elephants and people from harm.