A preliminary study of the effects of ecologically relevant sounds on the behaviour of captive lowland gorillas (1994)

Ogden, J. J., Lindburg, D. G., Maple, T. L.

Abstract

Moderate levels of noise associated with captive animal housing, particularly intermittent noises, may be stressful for animal inhabitants. This is particularly noteworthy in that these effects did not disappear over time, countering those who might suggest that 'noise is okay, because animal will get used to it'. ... Rain forest sounds acted to ameliorate effects of noise conditions in the two infants but not in the two adults.