The effects of different enrichment types within the order Carnivora
05 Apr 2021
The effects of different enrichment types within the order Carnivora: Investigation into the potential benefits of auditory enrichment within captive felids
By Jen-Yun Chou
Take home message: Enrichment has a stronger effect on felids compared to canids as suggested by the meta-analysis. Auditory enrichment showed a tendency to reduce pacing behaviour in the cheetah.
Captive wildlife welfare gains increasing attention, and one of the concerns is the commonly observed stereotypic behaviours in zoos. Stereotypic behaviours are defined as “repetitive, invariant behaviour without obvious goal or function,” the extent of which differs between animal orders and species. Monotonic environment, lack of stimulation and failure to express natural behaviours can lead to stereotypic behaviours, and it is considered a symptom of chronic stress and low welfare status. Although in some animals, the display of stereotypies does not necessarily associate with impaired reproductive success, which is also considered a welfare indicator. Environmental enrichment is widely utilised in many zoos to improve animal welfare by providing a more stimulating environment. There is a wealth of literature on the effectiveness of different types of enrichment, including visual, olfactory, textile and dietary, for various species. However, auditory enrichment has been less discussed, especially for the family Felidae, which was the focus of this thesis.
This study used five different species of felids as subjects, including a white lion (Panthera leo), a tiger (Panthera tigris), an Amur leopard (Panthera pardus orientalis), a cheetah (Acinonyx jubatus) and a serval (Leptailurus serval) in a crossover design. The auditory enrichment used was composed of sound clips of Afrotropical and rainforest ambiance. All subjects were exposed to the auditory enrichment for 15 days. Before introducing the enrichment, a baseline observation was conducted for 15 days. All subjects were observed continuously for 30 minutes around the same time on each observation day using a predefined ethogram (resting, locomotion, standing, grooming, vocalisation and pacing, which is the most common stereotypic behaviour observed in felids). Besides the empirical study, a meta-analysis was also conducted, to compare the effectiveness of enrichment for the order Carnivora.
Results from the empirical study showed that auditory enrichment did not influence the subjects’ behaviours, however, it tended to reduce the pacing behaviour observed in the cheetah. The meta-analysis suggested that environmental enrichment in general had a greater effect on felids as compared to canids. No difference in the effectiveness of the type of enrichment (environmental, dietary, olfactory, and auditory) was found, but olfactory and auditory enrichment types were more effective for felids than canids, while auditory enrichment was shown to negatively impacted canids.
As the empirical study was limited in the number of subjects that can be observed, no effect was found between the five species chosen. Nevertheless, a tendency was found to decrease cheetah’s pacing behaviour, which demonstrated the potential of auditory enrichment for felids, especially considering its lower cost requirement for practical use in zoos. The meta-analysis further demonstrated that felids could benefit from appropriate environmental enrichment, with a better response to olfactory and auditory types. This attests further investigation into the effectiveness and practicality of auditory enrichment for a larger sample of captive carnivores.
Niamh Bews who studied Zoology at the Aberystwyth University conducted this study in the Big Cat Sanctuary. She said, “I really enjoyed doing this research project and worked really hard on making it as good as possible, so to be one of the 12 shortlisted is a great honour and I’m incredibly grateful.” She is currently doing her master’s dissertation on the impact of illegal wildlife trade. In the future, she hopes to continue her passion for in situ conservation, monitoring populations and working with local communities, and advance to PhD research in this area.
Jen-Yun Chou, University of Pennsylvania
Jen-Yun joined the BSAS Early Career Council in 2019 and completed her PhD project with Teagasc and SRUC on the strategies to manage tail biting in pigs in the same year. She worked as a Global Animal Welfare Advisor for World Animal Protection before starting her current role as a postdoctoral researcher at the Swine Teaching and Research Center (Department of Clinical Studies, New Bolton Center, School of Veterinary Medicine) at the University of Pennsylvania.