Monkeys in a Finland zoo have shown a significant preference for traffic noises over nature sounds, researchers have found.
A tunnel fitted with sensors was installed in a monkey enclosure at Korkeasaari Zoo in Helsinki. This allowed white-faced saki monkeys, the native to northern countries of South America, to choose whether they listened to a playlist of traffic noises, nature and falling rain - or a choice of either zen music and dance music, reports Science Times.
Dr Ilyena Hirskyj-Douglas, a researcher at Aalto University in Finland said that researchers thought they would enjoy more calming sounds, such as traffic, rain, zen sounds, and dance music but actually they prefer traffic noise over the natural sounds and other soothing music.
The traffic playlist was the most popular choice among the monkeys, who also groomed themselves or each other and sometimes slept when the sounds were playing - something they did not do for any of the other noises.
Kirsi Pynnonen, the zoo's research coordinator said that the sounds of the road mimic some of the ways in which the animals naturally communicate.
She said in the wild, the animals "use high-pitched hissing, squeaking and croaking to stay in contact", indicating that they may hear these noises in the traffic sounds too.
The research was part of an experiment looking into how technology can be used to improve the wellbeing of animals in captivity.
According to the researchers, this is the first time a sound experiment has given animals full control over what they would like to listen to.
They hope that these findings could allow zoos to provide extra stimuli to animals within their enclosures in the future.
Dr Hirskyj-Douglas said the animals could one day control their own lighting or temperature settings, and perhaps play games.
"The technology is very much open and we're just starting to bridge into this area," she said.
As a part of the next step, the research team is planning to install screens within the tunnels for monkeys to watch if they want to.