Visitors' effects on the welfare of animals in the zoo: a review

Davey reviewed the evidence on how the presence, number and behaviour of visitors affect captive zoo animals. He found that visitors can act as a source of stress, enrichment or both depending on species, individual and context, with large, noisy or active crowds more often associated with avoidance, vigilance and behavioural change. The review distinguished studies showing negative, neutral and positive visitor effects and called for better methodology to separate visitor presence from confounding variables. It became a key reference framing the 'visitor effect' as a real but variable welfare factor. For felids, which often retreat or increase vigilance under crowd pressure, it informs exhibit design that gives cats control over visibility.