London, August 25 : Authorities at Bristol Zoo in South West England have been ordered to keep two gibbons indoors at least three nights a week, as they create a lot of noise while making love.
According to reports, the amorous gibbons - Duana, seven, and 11-year-old Samuel - could be heard two miles from the zoo.
Environmental experts measured the apes at an ear-splitting 100 decibels, after neighbors complained about the passionate "whooping", especially around sunset and sunrise.
Zoo authorities were later ordered to keep them indoors at least three nights a week.
"We don't normally like to keep them inside, but they can be quite noisy," the Mirror quoted a Bristol Zoo spokesman as saying.
Cambridge primate expert Dr David Chivers said: "People should be grateful to hear them - it's like a beautiful symphony."