The principal method of assessing a captive animal’s welfare is by observing their behaviour and comparing it to its wild relatives (Carlstead, 1996). Enrichment often takes the form of a complex, diverse enclosure where the individual can, for example forage for food, mark its territory and maintain its physical condition which allows the lemurs to exhibit more ‘natural’ behaviours by exhibiting some control over their environment and thus maintain high welfare standards (Carlstead, 1996). Whilst previous studies suggested visitors resulted in negative behaviours in primates (Chamove et al., 1988), more recent work suggests that the presence of humans within their enclosure is a form of enrichment for ring-tailed lemurs (Simpson, 2004). The aim of the study was to investigate the effect of the ‘traditional’ versus the larger, more varied walk-through enclosure on the behaviour of ring-tailed lemurs.