“But behind the scenes, you’ve got animal keepers who know each and every one of those monkeys,” Drew Mullin, the park’s director, told the BBC. “They know them by name, and every day when they come in, they go to see them. This morning they didn’t.”

No other animals in the park were harmed.

The park is part of the country estate around Woburn Abbey, home to the 15th Duke of Bedford. It is famous for the family’s decision, when many other British aristocrats were passing expensive-to-run stately homes to a heritage charity, to retain ownership and open their ancient seat as a tourist attraction.

They added the safari park and other attractions to the abbey, which sits in a scenic deer park amid rolling green hills and houses a large art collection.

Woburn Safari Park has not been the only such attraction to suffer grim news in recent weeks.

At London Zoo last month, a fire killed an aardvark and left four meerkats missing and presumed dead. Several employees were treated at the scene for smoke inhalation and shock.

And on Tuesday, Berlin’s Tierpark zoo announced the death of a polar bear cub. She was the second cub born to the zoo’s 8-year-old Tonja, whose firstborn, Fritz, died last year of a liver infection. Tierpark is the eastern counterpart of the Berlin Zoological Garden, whose most famous polar bear, Knut, died in 2011.