Although they have never been given the chance to live in their wild homeland in Africa, primates held captive at zoos still find solace in listening to the sounds of the jungle.
Researchers studying the effect of music on a group of lowland gorillas at the Buffalo Zoo in New York found that nature sounds, more than classical music or even silence, reduced outward indications of anxiety and stress.
Over the course of several weeks, the gorillas were introduced to three different types of music, played through hidden speakers inside their enclosure: a mix of classical compositions from composer Chopin; songs from the rock band Muse; and tracks from a "Sounds of Nature" compilation. While the sounds were played, researchers watched for tell-tale signs that the animals were stressed -- for example, repetitive behavior like hair-plucking or regurgitation of food.
Interestingly, while this behavior increased by as much as 40 percent when both rock and classical music was played, it actually decreased when sounds resembling their natural habitat played -- even more so than when no sounds were played at all.