Many captive giraffes perform oral stereotypies, in particular tongue-playing, licking of objects (including conspecifics) and vacuum chewing. Typically, the diet of these large ruminants in captivity consists mostly of food concentrates, which are consumed rapidly and do not provide stimulation for their long, prehensile tongues. In the wild, browsing requires extensive use of this organ but in captivity material upon which to browse is limited. Consequently, vacuum activities, such as mock leaf-feeding behaviour, and stereotypies may develop. Rumination is also a major component of a giraffe's behavioural repertoire. It is essential for proper digestion, but may also be connected with non-REM sleep. Inadequate opportunities for rumination may also contribute to the development of oral stereotypies. In this study of captive giraffes, we examined the effect of increasing dietary fibre on the time spent ruminating and feeding and the extent to which oral stereotypies were performed. Two giraffes of different age, sex and sub-species were studied at Paignton Zoo Environmental Park. Dietary fibre was increased by the addition of coarse meadow hay to their existing diet. Following the addition of hay, time spent feeding did not change significantly but there was a significant increase in the time spent ruminating and a significant reduction in time spent performing oral stereotypies by both giraffes, suggesting that oral stereotypies may be connected with rumination rather than feeding. Stereotypic behaviour is generally accepted to be an indicator of sub-optimal welfare. Thus, the reduction in this behaviour by the simple addition of coarse fibre to the diet can be interpreted as enhancing the welfare of these animals.
