Abstract: Studies on three species of big cats at Dublin Zoo have led to firm conclusions about the effects of certain forms of enrichment, some of which will be presented here. Lions, jaguars, and snow leopards were studied over two years and their behaviours quantified using focal animal sampling during selected hours during daylight. By comparison of these activity budgets with and without the enrichments being present, it was possible to identify the exact behavioural changes caused by each enrichment method, and to quantify these changes. In this contribution we present results showing that the presence of a platform in both lion and jaguar enclosures dramatically reduced stereotypic pacing behaviour. We will demonstrate that the effects of short term enrichment devices may have a wide range of effects on behaviours which outlast the presence of the stimulus. For instance scents added to the cage, or food/play items such as horse hides, hidden fish or ice-blocks often reduce pacing and increase resting later in the day, even after the cats have ceased using the enrichment items. This reduction in pacing and increase in resting time often meant that the amount of the enclosure used per hour was actually reduced with the presence of new stimuli, as result opposite to what might have been expected. The results of these studies will be discussed in relation to effective animal management.