Historic Zoo Baffled After Monkeys Mysteriously Die After Exhibiting 'Unusual Behavior'

The sudden demise of several monkeys has left Hong Kong zoo officials baffled as they struggle to identify the cause of the deaths.

Hong Kong Chief Executive John Lee announced in a press briefing on Tuesday that part of the Hong Kong Zoological and Botanical Gardens would be sealed off for investigation following the unexplained deaths of 9 monkeys in two days.

"Whenever we have any news, if there's a new development, an announcement should be made as soon as possible, so that everyone can know about the facts," Lee said.

Experts have been brought in to conduct necropsies and toxicological tests as the monkeys exhibited unusual behavioral patterns and appetites before they died, AP News reported. 8 monkeys were found dead in enclosures on Sunday, with one additional monkey being found dead on Monday.

Among the deceased are a De Brazza's monkey, a common squirrel monkey, four white-faced sakis and three critically endangered cotton-top tamarins. Another De Brazza's monkey is currently under observation for exhibiting similar abnormal behavior.

Kevin Yeung, Secretary for Culture, Sports and Tourism, called an urgent interdepartmental meeting with the Leisure and Cultural Services Department, the Agriculture, Fisheries and Conservation Department and the Department of Health concerning the deaths on Monday. The Leisure and Cultural Services Department released a statement Tuesday night indicating that the other monkeys remained in stable condition.

The other 80 animals in the garden were not exhibiting any unusual behavior and are in stable condition, said an interdepartmental statement.