Chester Zoo is mourning the loss of Cleo the chimpanzee who died last week.

Cleo, who had been at Chester Zoo for more than 30 years, was one of the most distinctive attractions among the monkeys and apes.

Not only was she the dominant female of the group, 41-year-old Cleo was also instantly recognisable due to her large rear swelling.

Cleo’s distinctive rear often gave rise to concern among visitors who sometimes feared the chimp may have some kind of tumour, when in fact it was just a fatty mass that never caused her any problems.

Chester Zoo is mourning the death of Cleo the chimpanzee
Chester Zoo is mourning the death of Cleo the chimpanzee
 

So far Chester Zoo has not revealed any details concerning the circumstances of her death.

However, the following statement was released today:

“Sadly our 41-year-old chimp Cleo did pass away towards the end of last week.

“Cleo, who was easily recognisable by her large rear swelling, had been at the zoo for over 30 years having come from Twycross Zoo in 1981.

“Although she did not rear any offspring of her own she was always very popular with the youngsters in the group and for many years had been the dominant female.

“She will, of course, be sadly missed by the group and the keepers who have been looking after her for many, many years.”

Cleo was one of the subjects of a research project carried out by Nicole Scott of the University of Minnesota in America earlier this year.

The project aimed to see if there was anything that could be learned about the relationships between men and women from the behaviour of male and female chimpanzees.

As part of her findings, Ms Scott described Cleo as the ‘auntie’ of the group.

Cleo was believed to have been one of the 30 chimps who staged a daring escape attempt in 2009. The primates found their way out of their enclosure into a nearby keepers' area, where their food is usually prepared.

About 5,000 visitors were asked to leave the zoo site as a security measure.

The then director general of the zoo, Gordon McGregor-Reid, said at the time: “It was a bit like an old-fashioned chimps tea party... they've certainly had a ball in that room that's for sure.”