Sensory enrichment - auditory
Before we begin, it’s important to point out that, while auditory enrichment can be a positive thing, it can also be negative. Throughout this short post we will take a look at how this can happen and what to consider when creating auditory enrichment for captive tigers.
A tiger’s sense of hearing is acute. This sharp sense helps the animal to hunt prey and survive in the wild. However, in captivity, considerations regarding the tiger’s environment are often overlooked, and may lead to an increase in stress. In order to provide good animal welfare, environmental sound should be taken into consideration. Noises of people, cars and electronic sounds such as music and loud PA systems can be stressful to the tiger potentially increasing stress-related behaviours. However, other sounds can help to promote positive welfare.
Zoos have found that playing natural sounds or even classical music has helped to reduce stress levels to other species. This finding also applies to domestic animals, such as dogs, who show more relaxed behaviours such as calmly lying. Music doesn’t have to be classical music either as the same study showed that dogs enjoyed listening to soft rock and reggae ! However, the key to success is to ensure that the music was changed regularly, as the more relaxing effects appeared to wear off if the same music was played constantly. There is also evidence of a degree of personal preference, with some dogs responding more positively to some genres over others – and the same is true of tigers, highlighting the importance of considering personality and individuality when providing enrichment.
For tigers, natural sound, such as animal vocalisations, can also be played. These can be sounds of other tigers, but these need to be carefully chosen to ensure the sound elicits positive behaviours. For example, a male tiger hearing another male tiger could find that quite stressful and spend more time performing agonistic behaviours rather than positive ones. On the flip side, a female hearing the call of a male might respond positively. This does mean that careful study needs to be implemented as to what is best for each individual tiger.
Prey sounds or distress calls can also be used as enrichment. This could stimulate the tiger’s natural hunting instinct to search for and hunt prey. Such sounds can promote more positive seeking or hunting activity. Again though, there is a risk that this type of sound could be frustrating when the tiger is unable to find the source thus causing frustrated stereotypies to surface.
However, if these prey sounds are combined with food rewards, the payoff might be more rewarding. A study with an African leopard  showed that the leopard learned to pursue the bird sounds in order to obtain food treats. After an extended period of time, all the sounds were captured resulting in the leopard collecting all treats provided using a feeder belt. In addition to this, the levels of stereotyping decreased, and the leopard continued to use the feeder.
As sounds can have negative as well as positive benefits, the types of audio used need to be carefully considered to ensure they promote positive or relevant behaviours. Overall, more research needs to be done in this area to ensure the sounds are not only welfare oriented for tigers in general but will also match the specific tiger receiving the enrichment.
1. Bowman, A., Scottish SPCA, , Dowell, F.J. and Evans, N.P. (2017) The effect of different genres of music on the stress levels of kennelled dogs. Physiology and Behavior 171, pp. 207-215. (doi:10.1016/j.physbeh.2017.01.024)
2. Markowitz, H., Aday, C. and Gavazzi, A. (1995). Effectiveness of acoustic ‘prey: Environmental enrichment for a captive African leopard (Panthera pardus).Zoo Biology. https://doi.org/10.1002/zoo.1430140408